0.92

BUG FIXES:

- Reverse engineering with MySQL broke when the tables were returned
  _without_ the schema name.

- Enable subselects for MySQL, though there's still no good API for
  subselects.

- Pass any unknown command line options through to Module::Build, for
  example things like "--install-base". Reported by Lars Dieckow. RT
  Ticket #28410.

- Fix a possible bug in Alzabo::Config::available_schemas. Reported by
  Otto Hirr. RT Ticket #28312


0.91  Mar 25, 2007

BUG FIXES:

- Alzabo checked whether a particular variable was an array reference
  with a construct like this "eval { @$thing } ? @$thing :
  $thing". Under most circumstances, this is ok, but Mason installs a
  $SIG{__DIE__} handler that turns all string exceptions into
  exception objects. This meant that under Mason, for any eval where
  the reference in question was _not_ an array reference, a string
  exception was caught and turned into a full-blown exception
  object. This could cause a massive performance hit in some cases.


0.90  Mar 9, 2007

ENHANCEMENTS:

- Added handling of multi-column indexes which include one function
  when reverse-engineering Pg schemas.


BUG FIXES:

- When a row was deleted, it was not being deleted from the cache. If
  you then inserted a row with the same primary key, you got back the
  row from the cache, which was marked as deleted, instead of the new
  row.

- Newer versions of MySQL may return fully qualified and quoted table
  names (`Schema`.`Table`) from $dbh->tables. This broke
  reverse-engineering.

- The Alzabo::Column->is_time() method was totally broken for MySQL.


0.8904  Nov 17, 2006

BUG FIXES:

- The t/21-row_by_pk-exception test blew up if no test config was
  provided, instead of just skipping its tests gracefully. Reported by
  Andy Lester.


0.8903  Nov 16, 2006

BUG FIXES:

- The change in 0.8902 to not use UNIVERSAL::isa exposed a bug in the
  handling of an attempt to load a row which doesn't exist in the
  DBMS. Reported by Jon Prettyman.


0.8902  Nov 9, 2006

BUG FIXES:

- Make Alzabo "safe" to use with UNIVERSAL::can (the module), which
  spits out lots of warning if you use Alzabo after it has been
  loaded.

- Fixed a warning from DBI in the 03-runtime.t tests.

- Fixed reverse engineering of nextval() as a column default with Pg.


0.8901  Jul 19, 2006

BUG FIXES:

- Fix reverse engineering of "now()" as default for a column with Pg.


0.89  Jun 20, 2006

ENHANCEMENTS:

- Improved schema diffs for Postgres, particularly in the area of
  comparing two columns. Now we attempt to determine if two columns
  are logically equivalent, even if they might have minor variations
  (INT vs INTEGER type name, 'f' versus 'false' for BOOLEAN default,
  etc.).

- Added Alzabo::SQLMaker->distinct_requires_order_by_in_select for the
  benefit of Pg, which requires that anything in the ORDER BY clause
  show up in the SELECT when you SELECT DISTINCT. This change is
  experimental, and may go away in future versions.

- Removed support for passing order_by and group_by as a hash
  reference. This was deprecated in 0.59.

BUG FIXES:

- When reverse engineering a Postgres schema, Alzabo did not look for
  its own sequences to determine if a column should be marked as
  sequenced.

- Defer FK creation until all other DDL has been executed. This
  ensures that the table to which we're referring will be available.

- When recreating a table during a SQL diff, make this an exception so
  we don't do other column diff/add/drop operations on the same table.

- Fixed a test failure in 07-methodmaker.t when testing with
  Postgres. This failure may not have showed up often because it came
  from a test that depended on the DBMS returning rows in a speific
  order by without specifying an ORDER BY.

- When a Postgres table is renamed, its sequences are also renamed.


0.8801  Mar 13, 2006

BUG FIXES:

- Quoting of PostgreSQL column defaults in DDL SQL was completely
  broken.


0.88  Mar 13, 2006

ENHANCEMENTS:

- Added a new option when creating a column, "default_is_raw", which
  can be used to allow for a function like NOW() as a column default.

- Added an "--automated" option for Build.PL, to force it to just use
  default prereqs. Also added other options to be used with this one,
  see "perl Build.PL --help" for detalis.

- The Alzabo::Driver classes will now transparently reconnect to the
  DBMS if you attempt to use them in a child process after a
  fork. This prevents various problems that can occur if you attempt
  to share a DBI handle between two processes. One notable problem is
  that the parent's DBI handle is closed when the child exits.

- Added support for (VAR)BINARY type columns in MySQL. Request by
  Martin Groenemeyer. RT Ticket #16338.

BUG FIXES:

- Alzabo::Table->foreign_keys_by_table() and foreign_keys_by_column()
  could return the same object more than once when using
  multiple-column foreign keys. Reported by Rainer Rohmfeld. RT Ticket
  #13885.

- Calling connect() on a driver object (via a schema object) with
  different parameters did not reconnect if the existing handle was
  still good. This was explicitly opposite what the docs said the code
  was doing. RT Ticket #17942.

- Fix bug in reverse engineering function indexes in Postgres.  The
  reverse engineering code always ended up thinking all of the columns
  in the table were used in the index.

- Fix failing MySQL test in 03-runtime.t.  The problem was the test,
  not the Alzabo core.  Reported by Alex McLintock.

- Fixed adding too many "=cut" directives in docs generated by
  Alzabo::MethodMaker.

- Fixed SQL generation for the Postgres functions CURRENT_DATE,
  CURRENT_TIME, and CURRENT_TIMESTAMP, which should not have
  parentheses after them.

- Documented that DATE_TRUNC() is a support Pg function in
  Alzabo::SQLMaker::PostgreSQL. RT Ticket #13843.


0.87  May 14, 2005

BUG FIXES:

- Table names in CREATE INDEX statements for Postgres were not quoted.

- Database names in CREATE/DROP DATABASE statements for Postgres were
  not quoted.

- Postgres database names with upper case characters were never being
  detected as being instantiated, which meant Alzabo always tried to
  recreate the schema from scratch.

- ALTER TABLE statements for Postgres left the table name unquoted
  when renaming a column.

- Even if Alzabo::Runtime::Schema->referential_integrity was false,
  Alzabo was still doing referential integrity checking on inserts.
  Reported by Michal Jurosz.

- 19-schema-name.t did not use the user-supplied connection parameters
  and could fail because of this.  Reported by Daniel Puro.

- Handle quotes in table names returned by Postgres when reverse
  engineering.

- Reverse engineering a Postgres schema that contained indexes on
  functions could fail because the Alzabo::RDBMSRules::PostgreSQL code
  used a function from Text::Balanced without loading it first (or
  making it a prereq for the distro).  Reported by an anonymous user
  via rt.cpan.org.

- When getting the next sequence number from a Postgres schema, Alzabo
  was not quoting the sequence name even if the schema's
  quote_identifiers attribute was true.  Reported by "Martin" via
  rt.cpan.org.

ENHANCEMENTS:

- Allow any key starting with "pg_" when connecting a Postgres
  database.  This allows you to pass attributes like "pg_enable_utf8"
  or "pg_bool_tf".  Prompted by a discussion with Boris Shomodjvarac.


0.86  December 22, 2004

BUG FIXES:

- Allow a UNIQUE constraint as a column attribute for MySQL.

ENHANCEMENTS:

- It is now possible to use a single Alzabo schema object to create
  and access multiple copies of that schema in an RDBMS.  This is done
  by setting the "schema_name" parameter whenever calling a method
  that accesses the RDBMS.

  This feature has a bad interaction with the way internal schema
  diffs are generated, however.  Please see the "MULTIPLE COPIES OF
  THE SAME SCHEMA" section in Alzabo::Intro for details.

- The Alzabo::Runtime::Row->update() method now returns a boolean
  indicating whether any changes were actually made.  Patch by Eric
  Waters.


0.85  October 12, 2004

BUG FIXES:

- The DECIMAL and NUMERIC column types in MySQL were not being treated
  as numeric types.  This meant that you couldn't give such a column
  the UNSIGNED attribute, among other problems.  Reported by Bob
  Sidebotham.

- If a column had CHECK constraints, the Postgres reverse engineering
  failed.  Reported by Ken Miller, fixed by Joshua Jore.

- Insert handles did not include sequenced Postgres columns, causing
  17-insert-handle.t to fail when run against Postgres.  Reported by
  Eric Schwartz.


0.84  September 4, 2004

ENHANCEMENTS:

- Alzabo::MethodMaker will now warn you when you it creates a method
  that overrides a parent class's method.  This can cause problems
  when you override the table class's name() method with one that
  returns a column object.


BUG FIXES:

- Make Alzabo::Create::Schema->delete work under taint mode.  Reported
  by Dana Hudes.

- Improve Alazbo::PostgreSQL docs, specifically mentioning that if you
  create a Postgres schema with mixed or upper case table names, you
  need to do $schema->set_quote_identifiers(1) for any DML SQL to
  work.

- The Alzabo::Runtime::Row->is_potential method didn't exist.

- The caching had a very nasty interaction with reverse engineering
  that could cause data loss (of foreign keys) when the "sync with
  backend" functionality was called from the Mason GUI.  There may
  have been other bugs as well.  This was fixed by not caching reverse
  engineered schemas, which is somewhat of a hack.

  Anyone using the Mason GUI with MySQL is encouraged to upgrade
  because of this bug.


0.83  June 9, 2004

MISCELLANEOUS:

- I got fed up with the instability of CVS on Sourceforge, and am now
  using a Subversion repository I host myself.  See "source" page on
  www.alzabo.org for details.


ENHANCEMENTS:

- All SQL-generating methods for the Alzabo::Runtime::Schema and
  Alzabo::Runtime::Table classes now accept a "quote_identifiers"
  parameter, which allows you to turn this on for a single query.

- Improved handling of MySQL's "default defaults" when reverse
  engineering or comparing two schemas, so that the code doesn't
  generate ALTER TABLE statements that don't do anything.

- Make many Params::Validate specs into constants, which may improve
  speed a bit, and may affect memory usage under mod_perl.  This is
  probably a useless micro-optimization, though.


BUG FIXES

- Make sure generated SQL for Postgres schema diffs does not include
  dropping & adding the same FK constraint more than once.

- Reverse engineering works with Postgres 7.4.  Thanks to Josh Jore
  for this big patch.  Hopefully this won't break anything for
  Postgres 7.3 ;)

- The Alzabo::Column->is_time_interval method was misspelled, and so
  did not work at all.  Patch from Josh Jore.

- With Postgres 7.4, the DBI tables method always includes system
  tables, so we have to filter these out in the
  Alzabo::Driver::PostgreSQL->tables method.  Patch from Josh Jore.

- Make the is_date & is_datetime method consistent across various
  databases.  For Postgres, is_date was only returning true for the
  DATE type, not TIMESTAMP.

- Make is_datetime return true for Postgres' TIMESTAMPTZ column type.

- Turning on SQL debugging could cause Alzabo to alter bound values
  that were null to the string "NULL" before performing a query.

- If a table name was changed and an index, column, or foreign key
  dropped from that table, then the generated "diff" SQL could refer
  to the old table name in the various DROP statements that were
  generated.

- Workaround a bug in MySQL that reports a "Sub_part" of 1 for
  fulltext indexes.

- The changes introduced in 0.71 to track table and column renames
  could cause bogus SQL to be generated if something was renamed, the
  schema was instantiated, and then the schema was compared to an
  existing live database which also had the same renaming done to it.

- If you tried to create a relationship between two tables where one
  of the tables had a varchar or char column as part of its PK, and
  you let Alzabo create the foreign key column in the other table,
  then Alzabo would try to set the length of the varchar/char column
  to undef, which would cause an exception to be thrown.

---------------------------------------------------------------------------

0.82  January 6, 2004

ENHANCEMENTS:

- The Alzabo::Runtime::Table->insert() and
  Alzabo::Runtime::InsertHandle->insert() methods will not create a
  new row object when called in void context.  This should make
  inserts faster when you don't need a row object back.

- When reverse engineering a MySQL schema, Alzabo will now set a table
  attribute for the table type (MyISAM, InnoDB, etc.) if the server
  supports table types (which any modern version of MySQL does do).

BUG FIXES:

- When creating the test database for MySQL, we now explicitly set the
  table type to MYISAM, in case the default is something else.
  Otherwise the tests will fail when we try to create a fulltext
  index.

KNOWN BUGS:

- This release will fail several tests when tested with Postgres 7.4.
  Specifically, reverse engineering with Postgres 7.4 is known to be
  broken.  This will be fixed in the next release.

---------------------------------------------------------------------------

0.81  December 21, 2003

ENHANCEMENTS:

- Added a new insert handle feature, which should be significantly
  faster for batch inserts than repeatedly calling the table class's
  insert() method.  Development funded by Marigold Technologies.

BUG FIXES:

- An order_by parameter that contained two SQL functions (like
  "COUNT(*) DESC, AVG(score) DESC") caused the error "A sort specifier
  cannot follow another sort specifier in an ORDER BY clause".

- If you passed a no_cache parameter to a method that created a row,
  this would cause an error unless Alzabo::Runtime::UniqueRowCache had
  been loaded.

- Workaround for bug/change/something in DBD::Pg 1.31+ that affects
  the $dbh->tables method, which broke reverse engineering.

---------------------------------------------------------------------------

0.80  October 24, 2003

ENHANCEMENTS:

- Use the non-deprecated form of DBI->tables().

- Added an is_time_interval method to Alzabo::Column.

- Lots and lots of doc cleanup and re-formatting.

---------------------------------------------------------------------------

0.79_04  October 18, 2003

- Identical to 0.79_03 except for minor POD changes in order to try to
  fix the problem of search.cpan.org treating the wrong file as the
  main Alzabo.pm docs.  Again reported by Darren Duncan.

---------------------------------------------------------------------------

0.79_03  October 18, 2003

ENHANCEMENTS:

- Many doc rewrites and updates.

- Documented row state classes.

- Added back the no_cache parameter to avoid caching one or more rows.

- Moved the relevant documentation from Alzabo::Runtime::PotentialRow
  into Alzabo::Runtime::Row.

BUG FIXES:

- Fixed the NAME portion of the Alzabo::MySQL and Alzabo::PostgreSQL
  POD files so that search.cpan.org doesn't think Alzabo::MySQL is the
  Alzabo.pm file.  Reported by Darren Duncan.

- The 12-rev_engineer_pg_fk.t test would try to load DBD::Pg even if
  you weren't using Postgres, which would cause the test file to die
  if DBD::Pg wasn't installed.  Reported by Jost's smokehouse.

- More documentation updates to remove outdated information.

- Split out the documentation in Alzabo.pm into Alzabo::Intro and
  Alzabo::Design.

- Added a FAQ from a question on the mailing list.  Suggested by
  Terrence Brannon.

- Eliminated a circular reference between tables created via the
  Alzabo::Runtime::Table->alias() method, and the columns those alias
  tables contain.  This required the use of weak references.

  NOTE: Alzabo regular tables and columns have circular references to
  each other, but this normally isn't a problem because you generally
  want to keep a whole schema around all the time anyway.

---------------------------------------------------------------------------

0.79_02  October 17, 2003

ENHANCEMENTS:

- Added support for table attributes like MySQL's "TYPE = ..." or
  Postgres's "WITH OIDS".

- Added support for functional indexes in Postgres, like
  "LOWER(some_col)".  Funded by Kineticode, Inc. for Bricolage 2.0.

- Added column/table constraint/check reverse engineering for
  Postgres.  Funded by Kineticode, Inc. for Bricolage 2.0.

- The SQL generated for Postgres schemas now includes foreign key
  constraints.

- Added a new method to Alzabo::Runtime::Schema, prefetch_none().

- Added a new method to Alzabo::Table, has_index().

- Documented Alzabo::Runtime::UniqueRowCache.

- The definitions of the is_character and is_blob column methods have
  been clarified.  Note that these definitions have changed from the
  previous, undefined behavior.

- When a 1..1 or 1..n foreign key is added to a table, a unique index
  is created on the columns involved in the foreign key, unless those
  columns are part of the table's primary key.

BUG FIXES:

- Fixed a problem in the Makefile.PL which would cause it to fail even
  if you had Module::Build installed.  Reported by Ken Williams.

- Fixed (really, this time, I hope) a problem where the user-provided
  connection parameters were not respected in the 01-driver.t tests.
  Reported by Ken Williams.

- FK reverse engineering for Postgres sometimes got the cardinality of
  the relationship wrong, making it 1..1 when it should be 1..n.  This
  should be much improved in this release, though it may still have
  bugs.

- Removed references to the old caching code in various spots.

- Fixed handling of case_sensitive parameter to
  Alzabo::Column->has_attribute().

BACKWARDS INCOMPATIBILITIES:

- When you load a runtime schema, it now calls
  "$self->prefetch_all_but_blobs" in order to turn on pre-fetching by
  default, since for the vast majority of users, this is a huge
  performance improvement.  The new prefetch_none() method can be used
  to turn off all prefetching.

- The is_character column method now returns true for any text type
  column, regardless of size.

- The is_blob column method now returns true only for columns that are
  defined to hold binary data.

---------------------------------------------------------------------------

0.79_01  October 10, 2003

ENHANCEMENTS:

- Distribution is now signed with Module::Signature.

- Lots of refactoring of the row object internals to simplify the
  code.  Implemented by Ilya Martynov.

- The testing code has been cleaned up quite a bit, and all of the
  utility functions used in the tests have been consolidated in
  t/lib/Alzabo/Test/Utils.pm.

- Added intermediate table and row classes for MethodMaker created
  classes, to provide a central point for adding new methods to table
  and row objects.  Based on a patch from Ken Williams.

- Support for "self-linking" tables in Alzabo::MethodMaker, a linking
  table which connects a table to itself in an n..n relationship.
  Implemented by Ken Williams.

- Added rdbms_version method to driver classes.  Implemented by Ken
  Williams.

- Added Alzabo::Create::Schema->is_saved() method.

- Foreign keys are now reverse engineered for Postgres 7.3+.
  Implemented by Ken Williams.

- Don't try to include dropped columns when reverse engineering
  Postgres 7.3+.  Implemented by Ken Williams.

- Do a better job of detecting SERIAL type columns when reverse
  engineering Postgres schemas.  Based on a patch from Ken Williams.

- Treat Postgres data types SERIAL4, SERIAL8, BIGSERIAL, and BIGINT as
  valid types.  Implemented by Josh Jore.

- NotNullable exception now include the table and schema name.  Based
  on a patch from Ken Williams.

- Primary keys are updateable.

- Debugging output from Alzabo::MethodMaker is clearer about what
  methods are being made.  Implemented by Ken Williams.

- Alzabo::MethodMaker will now create foreign key methods when two
  tables have multiple relationships, as long as the name generation
  callback returns different names for each of them.  Implemented by
  Ken Williams.

- A join parameter can now specify an outer join with a single array
  reference, such as:

    [ left_outer_join => $table_A, $table_B ]

  Previously, this could only be done as a double array reference, like:

    [ [ left_outer_join => $table_A, $table_B ] ]

- Various doc fixes and rewriting, most notably in Alzabo.pm.

BUG FIXES:

- A join using multiple aliases to the same table would fail with an
  error message like "Cannot use column (Foo.bar_id) in select unless
  its table is included in the FROM clause".

- Remove the long-ago deprecated next_row() and next_rows() methods.

- Postgres 7.3 allows identifiers to be up to 63 characters.  This
  broke the code that handled sequenced columns for Postgres.  Patch
  by Josh Jore.

- If you tried to create a relationship between two tables, and the
  "table_to" table already had a column of the same name as the
  "column_from" column, then Alzabo died with an error.  Reported by
  Ping Liang.

- If you had previously installed Alzabo, and then provided a new
  Alzabo root directory or a new directory for the Mason components,
  this was not respected during the installation process.

- Alzabo's referential integrity checks will no longer complain if you
  attempt to set a foreign key column to NULL.  Previously it would
  throw an exception if the column was part of the dependent table in
  a foreign key relationship.  Now, it just assumes you really meant
  to allow the column to be NULLable.

- The schema class's load_from_file() method now blesses the loaded
  schema into the calling class.  So if you use MethodMaker to
  generate classes, and then call My::Schema->load_from_file, it
  should always return an object blessed into the My::Schema class.
  Reported by Ken Williams.

- When checking for the MySQL variable sql_mode, the value may be
  simply '' as opposed to 0.  Patch by Andrew Baumhauer.

BACKWARDS INCOMPATIBILITIES:

- Alzabo now requires at least Perl 5.6.0 (5.6.1+ recommended).

- The old caching system has been removed, as it had way too much
  overhead.  There is a new, much simpler caching system provided by
  the Alzabo::UniqueRowCache module.

- The Alzabo::Runtime::Table->row_by_pk() method no longer dies if it
  cannot find a matching row.  Instead it simply returns false.

- Some deprecated MethodMaker options were removed: insert, update,
  lookup_table

- The Alzabo::Runtime::Row->delete() method now works for potential
  rows.

---------------------------------------------------------------------------

0.73  October 5, 2003

BACKWARDS INCOMPATIBILITIES:

- This release no longer includes the Mason schema creation GUI.  It
  can be installed separately via the Alzabo::GUI::Mason package.

BUG FIXES:

- Fixed a bug in Alzabo::Create::Schema that only seems to be
  triggered by newer Perls.  The symptom was an error like "Alzabo
  does not support the 'MySQL' RDBMS" when trying to create a new
  schema.

- Fixed a warning in Alzabo::RDBMSRules.

- The 01-driver.t test ignored any user-supplied RDBMS connection
  parameters.  Reported by Barry Hoggard.

- Newer versions of MySQL may return quoted table names, which broke
  reverse engineering.

- Added a quick and nasty hack to remove the schema name from table
  names when reverse engineering Postgres schemas.

- Reverse engineering of indexes for MySQL 4.0+ was broken.

---------------------------------------------------------------------------

0.72  April 12, 2003

ENHANCEMENTS:

- Rewrote the complex build/install system to use Module::Build, which
  simplified quite a bit of code.  Additionally, this should eliminate
  problems reported by Win32 users with the generated Makefile,
  because there is no longer a Makefile ;)

BUG FIXES:

- Fixed the Alzabo::MethodMaker->docs_as_pod method, which simply died
  when used with a recent version of Params::Validate.  Reported by
  Ken Williams.

---------------------------------------------------------------------------

0.71  April 6, 2003

ENHANCEMENTS:

- Alzabo now tracks table and column renames after a schema has been
  instantiated.  This means that when updating the schema in the
  database after such a change, Alzabo can ensure that there is no
  data lost because of the change.  Previously, Alzabo treated name
  changes as a drop followed by an add, which caused data loss.

- Alzabo::DriverStatement->next_hash has been renamed next_as_hash, in
  order to be consistent with the Alzabo::Runtime::Cursor classes.

- Experimental support for restriction clauses as part of an outer
  join, such as

    SELECT ...
      FROM Foo
           LEFT OUTER JOIN Bar
              ON Foo.foo_id = Bar.foo_id
                 AND Bar.something > 2

- Added support for HAVING in queries.

BUG FIXES:

- Exceptions did not include a stack trace.

- Trying to create a Postgres schema with foreign keys defined caused
  an exception.  Reported by Josh Jore.

- Fetching rows from the cursor for a join with multiple outer joins
  could fail if data was being prefetched.

DEPRECATIONS:

- Alzabo::DriverStatement->next_hash method has been renamed
  next_as_hash.

---------------------------------------------------------------------------

0.70  November 21, 2002

ENHANCEMENTS:

- The exception thrown when you attempt to set a non-nullable column
  to NULL is now an Alzabo::Exception::NotNullable exception, instead
  of an Alzabo::Exception::Params exception.  In the interests of
  backwards compatibility, the former is a subclass of the latter.

- Improved debugging options.  See the new Alzabo::Debug module for
  details.

BUG FIXES:

- Fixed Alzabo::Table->primary_key, which would die when no primary
  key existed and it was called in a scalar context.  In an array
  context, all the columns in the table were returned.  Reported by
  Eric Prestemon.

- Alzabo::ObjectCache::Sync::RDBMS created a table that it would later
  consider incorrect.  This made this module unusable.

- Alzabo::ObjectCache::Sync::RDBMS caused weird random errors when
  used with MySQL's InnoDB tables.

- In the schema creator, the link to the graph page, and the link _on_
  the graph page to the image, were both broken.

- Alzabo was allowing you to rename a column to the name of an
  existing column in a table.  Similarly, a table could be renamed to
  the same name as an existing table.  Doing this could trash a
  schema.

- Alzabo::Runtime::Table->one_row would return undef if no row was
  found, which in a list context evaluated to a true value.

- Allow no_cache option when calling Alzabo::Runtime::Schema->join.

- When displaying SQL, the schema creator now makes sure to
  HTML-escape it, because it's possible to have HTML in there (in a
  default, most likely).

- The "children" method generated by Alzabo::MethodMaker did not allow
  you to add additional where clause constraints to the query.

---------------------------------------------------------------------------

0.69  September 19, 2002

ENHANCEMENTS:

- Add count method to Alzabo::DriverStatement objects.

BUG FIXES:

- ** A particularly nasty bug sometimes manifested itself when
  removing a foreign key.  This bug caused the deletion of all foreign
  keys involving the _corresponding_ column(s) in the foreign table.
  Needless to say, this could make a big mess.

- Fix some typos in the generated docs created by Alzabo::MethodMaker.

- A join that included a where clause with an 'OR' generated improper
  SQL.  Reported by Ilya Martynov.

- Calling the Alzabo::Runtime::JoinCursor->next_as_hash method when
  the query involved an outer join could cause a runtime error.

- In where clause specifications, 'and' and 'or' were only being
  allowed in lower-case.  They are now allowed in any case.

- Aliases did not work in outer joins.  This has been fixed.

- Using outer joins was a bit fragile, in that the order of the outer
  join in the context of the other joins could cause Alzabo to
  generate incorrect SQL.  Now outer joins should work no matter what.

- A couple links in the schema creator had a hardcoded ".mhtml"
  extension, as opposed to using the value of
  Alzabo::Config::mason_extension().  Patch by Scott Lanning.

---------------------------------------------------------------------------

0.68  July 20, 2002

ENHANCEMENTS:

- Updated the thank you list in the README file (you too can be listed
  by sending me useful bug reports, patches, suggestions, or reminding
  that you already did so and I forgot ;)

- Allow the Driver's ->schemas method to take connection params,
  wherever possible.  This allows Alzabo::Create::Schema methods like
  ->create, ->sync_backend_sql, and ->sync_backend to work properly
  when the database server is on another machine.  Patch by Ilya
  Martynov.

- Added Alzabo::Runtime::*Row->is_live method to easily distinguish
  between real and potential rows.

- Did some profiling of data retrieval (Alzabo::Runtime bits) and
  optimized some of the most heavily used pieces of Alzabo.

- Added the Alzabo::Runtime::Schema->prefetch_all and
  Alzabo::Runtime::Schema->prefetch_all_but_blobs convenience methods.

- Added a ->count method to the cursor classes.

- Added ->is_integer, ->is_floating_point, ->is_date, ->is_datetime,
->is_time, and ->generic_type methods to column objects.

- The Alzabo::Driver->schemas method now takes connection parameters.
  See your specific driver subclass for details on which.  Bug report
  by Ilya Martynov.

- Added Alzabo::Runtime::Schema->disconnect method.  Patch by Ilya
  Martynov.

- Make the Makefile.PL act gracefully when it is invoked without a
  tty.  Patch by Ilya Martynov.

- The quoting of identifiers (table/column names) is now optional, and
  _off_ by default.  In profiling I found that a non-trivial amount of
  time was being spent quoting these, and in most cases it's not
  necessary.  There is now a
  Alzabo::Runtime::Schema->set_quote_identifiers method that can be
  used to change this behavior.

  Identifiers are always quoted when using Alzabo::Create::* with
  Postgres, however.

- Did a fair amount of profiling in order to optimize Alzabo's data
  fetching.  In general, Alzabo::Runtime::* operations should be
  faster.

- Added Alzabo::Runtime::Column->alias which is useful when executing
  queries via the Alzabo::Runtime::Schema and Alzabo::Runtime::Table
  ->select methods.

BUG FIXES:

- Alzabo::MethodMake generated "lookup column/table" methods will
  return if there is no matching entry in the related table, which is
  important when the two tables are independent.  Previously it would
  have been a runtime error (attempting to call a method on an
  undefined value).

- Fix warning from Row->update.  Patch by Ilya Martynov.

- Alzabo::Runtime::PotentialRow's id_as_string method was misnamed id.
  The docs had it wrong for all classes.

- Catch where clauses that contain non-column/function objects as left
  hand side value (like if you accidentally pass in a table object).

- The Postgres TEXT column type is now considered a blob, not a
  character type column.

- There was a fatal error when creating an n-to-n relationship if only
  columns were given, without tables.  This was fixed with a patch
  from Dan Martinez.

- Explicitly check for errors after calling $dbh->func.

- There was a bug when trying to use the schema creator to create
  relationships involving more than one column.

- Fixed a bug where a query using the Alzabo::Runtime::Table->one_row
  could cause an exception if no rows were found.

- Alzabo::Create::Schema->sync_backend was not passing through the
  connection parameters it was getting to the ->create method, causing
  failures.  Patch from Ilya Martynov.

---------------------------------------------------------------------------

0.67  June 6, 2002

BUG FIXES:

- There were some broken bits in the installation code in 0.66.  These
  are now fixed.

---------------------------------------------------------------------------

0.66  June 6, 2002

ENHANCEMENTS:

- It is now possible to retrieve auto-generated documentation to go
  along with the methods generated by Alzabo::MethodMaker.  See the
  "GENERATED DOCUMENTATION" section of the Alzabo::MethodMaker docs
  for more details.

- Added documentation to all the components in mason/widgets.  You can
  run perldoc on those files for more details.

- Added a very ugly hack to work around a bug with Storable 2.00 -
  2.03 and a Perl < 5.8.0.

- It is now possible to install Alzabo without defining an Alzabo root
  directory.  This means you will have to set this by calling
  Alzabo::Config::root_dir() every time you load Alzabo.  An attempt
  to load a schema without first defining the root_dir will throw an
  exception.  Based on a patch from Ilya Martynov.

BUG FIXES:

- Allow UNIQUE as a column attribute for Postgres.  Reported by Dan
  Martinez.

- Add DISTINCT back as an exportable function from the SQLMaker
  subclasses.  It may be useful when calling ->select and ->function.

- Fixed a bug that prevented things from being deleted from the cache
  storage.

- Fixed a variety of problems related to handling Postgres tables and
  columns with mixed or upper case names.  This included a bug that
  prevented them from being reverse engineered properly.  Reported by
  Terrence Brannon.

- Fixed a bug when altering a Postgres column name that caused Alzabo
  to generate incorrect syncing SQL.

- Make the test suite play nice with the latest Test::* modules.  The
  03-runtime.t tests were aborting because I feature I had been using
  in earlier versions of Test::More was removed.

- Alzabo::MethodMaker will die properly if given a non-existent schema
  name.  Suggested by Ilya Martynov.

- If you added a sequenced primary key to a table with MySQL, Alzabo
  did not generate all of the SQL necessary to change the table.
  Reported by Ilya Martynov.

DEPRECATIONS:

- The Alzabo::Schema start_transaction method has been renamed to
  begin_work.  The finish_transaction method is now commit.  The old
  names are deprecated.

---------------------------------------------------------------------------

0.65 May 16, 2002

INCOMPATIBILITIES:

- Alzabo now uses the natively created Postgres sequence for SERIAL
  columns.  If you have existing Alzabo code with SERIAL columns that
  is using the Alzabo-created sequence, then this release will break
  things for you.  One easy fix is to simply drop the existing
  Postgres-created sequence and recreate it with a new starting number
  one higher than the highest row already in existence.  So if your
  hightest "foo_id" value in the "Foo" table is 500, you would do
  this:

    DROP SEQUENCE foo_foo_id_seq;
    CREATE SEQUENCE foo_foo_id_seq START 501;

- The Alzabo::Table->primary_key method is now context-sensitive,
  returning a single column object in scalar context.

- The data browser is no longer installed, until such time as I can
  rewrite it to be more useful.

DEPRECATIONS:

- The Alzabo::Create::Schema->add_relation method has been renamed as
  Alzabo::Create::Schema->add_relationship.

ENHANCEMENTS:

- Check out the mason/widgets directory for some handy widgets that
  can help integrate Mason and Alzabo in useful ways.  These aren't
  really well-documented yet but may be useful for playing with.  More
  widgets will be included in future releases (I hope).

- When creating a relationship between tables in the schema creator,
  you can now let Alzabo figure out which columns to use instead of
  choosing them yourself.  For most relationships, Alzabo will simply
  do the right thing, adding a column to one of the tables as needed.

- The problems running the tests with Postgres should now be fixed.

- Fix stupid and inefficient internal handling of "SELECT DISTINCT"
  queries.  Now Alzabo simply lets the database handle this, the way
  it should have in the first place.

- The Alzabo::Runtime::Schema and Alzabo::Runtime::Table ->function
  and ->select methods now allow you to select scalars so you can do
  things like SELECT 1 FROM Foo WHERE ... in order to test for the
  existence of a row.

- Added Alzabo::Table->primary_key_size method, which indicates how
  many columns participate in the table's primary key.

- Added Alzabo::Runtime::Schema->row_count.  Suggested by Daniel
  Gaspani.

- Alzabo now detects older versions of schemas and transparently
  updates them.  This will work for all schemas created with version
  0.55 or later.

  See the section titled "Backwards Compability" in Alzabo.pm for more
  details.

- Added comment attribute for tables, columns, and foreign keys.

- Add VARBIT and TIMESTAMPTZ as legal types for Postgres.

- Handle SERIAL columns in Postgres better.  Use the sequence Postgres
  creates for the columns rather than making our own and just insert
  undef into new rows for that column.

BUG FIXES:

- Adding a column that is not-nullable or has a default to a table
  under Postgres was causing an error with Postgres 7.2.1.  It seems
  likely that with earlier versions of Postgres, this was simply
  failing silently.  Patch by Daniel Gaspani.

- Fixed buggy handling of joins that had a table with a multi-column
  primary key as the "distinct" parameter.

- Calling the Alzabo::Runtime::Schema->join method with no 'select'
  parameter and a 'join' parameter that was an array reference of
  array references would fail.

- Avoid an uninit value in Alzabo::MethodMaker.  Reported by Daniel
  Gaspani.

- If you created a cursor inside an eval{} block, the cursor contained
  an object whose DESTROY method would overwrite $@ as it went out of
  scope when the eval block exited.  This could basically make it look
  like an exception had disappeared.  Thanks to Brad Bowman for an
  excellent bug report.

- Loading a schema failed in taint mode.  This was reported ages ago
  by Raul Nohea Goodness and dropped on the floor by me.  My bad.

- The schema creator's exception handling was a little bit buggered up
  when handling Alzabo::Exception::Driver exceptions.

---------------------------------------------------------------------------

0.64 Mar 27, 2002

ENHANCEMENTS:

- Added potentially useful script, alzabo_to_ascii, in eg/ dir.

- Ask for port when setting up tests.

- Turn on stacktraces for all Alzabo::Exception objects.

- Removed the deprecated "lookup_tables" option from
  Alzabo::MethodMaker.

- Removed the deprecated next_row methods from the various cursor
  classes.

- Removed the deprecated Alzabo::Runtime::Table->func method.

- Major changes to how joins are done.  It is now possible to mix
  together various sorts of outer joins in a single query.  In
  addition, it is now possible to specify a foreign key that should be
  used when joining two tables.

- The "tables" parameter has been renamed as "join".

- The Alzabo::Create::Schema->right_outer_join and
  Alzabo::Create::Schema->left_outer_join methods have been removed.
  Use the ->join method instead, which can now be used to do outer
  joins as well, via:

    $schema->join( join => [ left_outer_join => $foo, $bar ], ... )

- The functionality of Alzabo::Runtime::OuterJoinCursor has been
  merged into Alzabo::Runtime::JoinCursor.

- Alzabo::Exception::Driver->bind now returns an array reference, not
  an array.

BUG FIXES:

- Fix failure to load schema objects from file when $\ is set to
  something like "\n".  Reported by Brad Bowman.

- Fixed Postgres reverse engineering to work with slightly changed
  system tables in 7.2.

- Fix handling of table alterations for postgres.  Temp tables were
  being created but not dropped and the data saved in the temp table
  was not being restored to the real table.  Also, Alzabo was trying
  to create sequences again when altering tables Based mostly on a
  patch from Daniel Gaspani.

- Fix handling of primary key changes for Postgres (I'm still not sure
  it's entirely correct).

- Fix detection of primary key changes for schema diffs.

- Handle NOT IN for where conditions.

---------------------------------------------------------------------------

0.63 Feb 18, 2002

ENHANCEMENTS:

- Calling Alzabo::Runtime::Row->select or
  Alzabo::Runtime::Row->select_hash with no arguments returns the
  values for all of the columns in the table.  Suggested by Jeremy
  R. Semeiks.

- The Alzabo::Runtime::Row->id method has been renamed to id_as_string
  for the benefit of those crazy people who like to use "id" as a
  column name and want Alzabo::MethodMaker to be able to create such a
  method.  Suggested by Alexei Barantsev.

- Changed the Alzabo::Create::Schema->sync_backend method so that if
  there was no corresponding schema in the RDBMS, then it will
  instantiate a new schema instead of just blowing up.  Similarly, the
  sync_backend_sql method will just return the SQL necessary to create
  the schema from scratch.

BUG FIXES:

- Removing column attributes via the schema creator was broken.
  Adding them could have caused errors but generally worked.

- If you changed a column from non-sequenced to sequenced, the SQL
  "diff" was not reflecting this.

- Revert a previous change to MySQL reverse engineering.  Now default
  for numeric columns that are not 0 or 0.00 are used instead of being
  ignored.  The fact that MySQL has 'default defaults' _really_ screws
  things up.  Bad MySQL!

- A query that ended with a subgroup could not be followed with an
  order by or group by clause.  Bug report and test case submitted by
  Ilya Martynov.

- Nested subgroups in where clauses (like where => [ '(', '(', ....)
  were not being allowed.  Bug report and test case submitted by Ilya
  Martynov.

- Alzabo::MethodMaker would overwrite methods in the
  Alzabo::Runtime::Row/CachedRow/PotentialRow classes.  This has been
  fixed.  Reported by Alexei Barantsev.

- Allow order by clause to contain only a SQL function to allow things
  like "SELECT foo FROM Bar ORDER BY RAND()", which works with MySQL.

---------------------------------------------------------------------------

0.62 Jan 15, 2002

ENHANCEMENTS:

- Add support for IFNULL, NULLIF, and IF for MySQL.

- Document that Alzabo supports COALESCE and NULLIF for Postgres.

- Added Alzabo::ObjectCache::Sync::Mmap which uses Cache::Mmap.  This
  is just slightly slower than using SDBM_File.

- New table alias feature for making queries that join against a table
  more than once.  An example:

    my $foo_alias = $foo_tab->alias;

    my $cursor = $schema->join( select => $foo_tab,
                                tables => [ $foo_tab, $bar_tab, $foo_alias ],
                                where  => [ [ $bar_tab->column('baz'), '=', 10 ],
                                            [ $foo_alias->column('quux'), '=', 100 ] ],
                                order_by => $foo_alias->column('briz') );

  In this query, we want to get all the entries in the foo table based
  on a join between foo and bar with certain conditions.  However, we
  want to order the results by a _different_ criteria than that used
  for the join.  This doesn't necessarily happen often, but when it
  does its nice to be able to do it.  In SQL, this query would look
  something like this:

    SELECT foo.foo_id
    FROM   foo, bar, foo as foo1
    WHERE  foo.foo_id = bar.foo_id
      AND  bar.foo_id = foo1.foo_id
      AND  bar.baz = 10
      AND  foo1.quux = 100
    ORDER BY foo1.quux

FEATURE REMOVAL:

- It is no longer possible to pass sorting specifications ('ASC' or
  'DESC') as part of the group_by parameter.  This was only supported
  by MySQL and it was broken in MySQL until 3.23.47 anyway.  It's
  weird and non-standard.  Just use order_by instead.

BUG FIXES:

- If prefetch wasn't set, all the rows in the table were being
  pre-fetched.

- The newest Test::More (0.40) uses eval{} inside its isa_ok()
  function.  The test suite was passing $@ directly into isa_ok() and
  it would then get reset by the eval{} in the isa_ok() function.
  This has been fixed by copying $@ into another variable before
  passing it into isa_ok().  Apparently, Test::More 0.41 will fix this
  as well.

- Make Alzabo::ObjectCache::Store::RDBMS and
  Alzabo::ObjectCache::Sync::RDBMS play nice with Postgres.  Postgres
  aborts transactions when there are errors like an attempt to insert
  a duplicate inside a transaction.  These module would just try to
  insert potentially duplicate rows and ignore the error.  Now
  Postgres is handled specially.

- If you told the installer that you didn't want to run any tests with
  a live database, there would be errors when it tried to run
  03-runtime.t.  Now it just skips it.

- Alzabo includes a script called 'pod_merge.pl' that is run before
  installing its modules.  This script merges POD from a parent class
  into a child class (like from Alzabo::Table into
  Alzabo::Create::Table) in order to get all the relevant
  documentation in one place.  The way the Makefile.PL ran this script
  was not working for some people, and in addition, did not end up
  putting the merged documentation into the generated man pages.  This
  release includes a patch from Ilya Martynov that fixes both of these
  problems.

---------------------------------------------------------------------------

0.61 Dec 25, 2001

ENHANCEMENTS:

- Improve documentation for new Alzabo::Create::Schema->sync_backend
  method and note its caveats.

- It is now possible to use SQL functions as part of order_by clauses.
  For example:

    my $cursor = $schema->select( select => [ COUNT('*'), $id_col ],
                                  tables => [ $foo_tab, $bar_tab ],
                                  group_by => $id_col,
                                  order_by => [ COUNT('*'), 'DESC' ] );

- Allow a call to Alzabo::Runtime::Table->insert without a values
  parameter.  This is potentially useful for tables where the primary
  key is sequenced and the other columns have defaults or are
  NULLable.  Patch by Ilya Martynov.

BUG FIXES:

- A call to the schema class's select or function methods that had
  both an order_by and group_by parameter would fail because it tried
  to process the order by clause before the group by clause.

- When thawing potential row objects, Alzabo was trying to stick them
  into the cache, which may have worked before but not now, and should
  be avoided anyway.

- The parent and children methods created by Alzabo::MethodMaker were
  incorrect (and unfortunately the tests of this feature were hosed
  too).

- Add YEAR as exportable function from Alzabo::SQLMaker::MySQL.

- Fix definition of WEEK and YEARWEEK functions exported from
  Alzabo::SQLMaker::MySQL to accept 1 or 2 parameters.

- A bug in the caching code was throwing an exception when attempting
  to update objects that weren't expired.  This only seemed to occur
  in conjuction with the prefetch functionality.  The caching code has
  been simplified a bit and is hopefully now bug-free (I can dream,
  can't I?).

- Make it possible to call Alzabo::Runtime::Schema->join with only one
  table in the tables parameter.  This is useful if you are
  constructing your join at runtime and you don't know how many tables
  you'll end up with.

- Where clauses that began with '(' were not working.  Reported (with
  a test suite patch) by Ilya Martynov.

- Where clauses that contained something like ( ')', 'and' (or 'or') )
  were not working either.

- This file incorrectly thanked TJ Mather for separating out
  Class::Factory::Util, but this was done by Terrence Brannon.  Oops,
  brain fart.

- Improve the recognition of more defaults that MySQL uses for column
  lengths and defaults, in order to improve reverse engineering.

- Recognize defaults like 0 or '' for MySQL.

- Fix Alzabo::Create::Schema->sync_backend method.

---------------------------------------------------------------------------

0.60 Dec 6, 2001

ENHANCEMENTS:

- When passing order_by specifications, it is now possible to do this:

    order_by => [ $col1, $col2, 'DESC', $col3, 'ASC' ]

  which allow for multiple levels of sorting as well as being much
  simpler to remember.

- It is now possible to do something like

    $table->select( select => [ 1, $column ] ... );

  and have it work.  In this case, every row returned by the cursor
  will have 1 as its first element.

- Added Alzabo::MySQL and Alzabo::PostgreSQL POD pages.  These pages
  document how Alzabo does (or does not) support various RDBMS
  specific features.

- Remove Alzabo::Util.  Use Class::Factory::Util from CPAN instead.
  Class::Factory::Util is a slight revision of Alzabo::Util that has
  been separated from the Alzabo core code by Terrence Brannon.
  Thanks Terrence.

- Add the ability to sync the RDBMS backend to the current state of
  the Alzabo schema.  This allows you to arbitrarily update the RDBMS
  schema to match the current state of the Alzabo schema.

- Add support for SELECT and WHERE clauses that use MySQL's fulltext
  search features.

- Add BIT and BIT VARYING as allowed types for Postgres.

BUG FIXES:

- Reverse engineering was not checking for fulltext indexes with
  MySQL.  These indexes were treated the same as other indexes.

- Make sure Alzabo::SQLMaker always handles stringification of
  functions properly.

- Improve recognition of default column lengths under MySQL (and
  ignore them).  Also improve recognition of default defaults (like
  '0000-00-00' for DATE columns) and ignore those.

- When using the BerkeleyDB module for object syncing or storage, the
  Berkeley DB code itself creates a number of temporary files.  These
  will now be created in the same directory as the storage/syncing
  file specified.

- Allow GROUP BY foo ASC/DESC for MySQL.  The MySQL manual claims this
  works.  In my testing, it accepts the syntax but doesn't actually
  respect the order requested.  Of course, you can always add order by
  clause with your group by and that seems to work just fine.

- Don't allow a GROUP BY clause to follow an ORDER BY clause.  The
  reverse is still allowed.

- MySQL: Allow fulltext indexes to include *text type columns without
  specifying a prefix.

- Dropping a column that had an index on it would cause an error in
  the generated SQL diff where Alzabo would drop the column and then
  try to drop (the now non-existent) index.  The fix is simply to drop
  the indexes first.

- Make caching code work under Perl 5.00503.

- Make code warnings clean (I think) under Perl 5.00503;

DEPRECATIONS:

- The way order_by and group_by parameters are passed has changed a
  bit.  In particular, this form:

    order_by => { columns => ..., sort => ... }

  has been deprecated in favor of a simpler syntax.

---------------------------------------------------------------------------

0.59 Nov 17, 2001

ENHANCEMENTS:

- Got rid of the post_select_hash hook and combined it with
  post_select, which now receives a hash reference.  Suggested by Ilya
  Martynov.

- Run all hooks inside Alzabo::Schema->run_in_transaction method to
  ensure database integrity in cases where your hooks might
  update/delete/insert data.  Suggested by Ilya Martynov.

- Added new Alzabo::Runtime::Table->select method.  This is just like
  the existing ->function method, but returns a cursor instead of the
  entire result set.

- Added a 'limit' parameter to the ->function method (also works for
  the ->select method).

- Added new Alzabo::Runtime::Schema->select method.  This is like the
  method of the same name in the table class but it allows for joins.

- Added new potential rows, which are objects with (largely) the same
  interface as regular rows, but which are not (yet) inserted into the
  database.  They are created via the new
  Alzabo::Runtime::Table->potential_row method.  Thanks to Ilya
  Martynov for suggestions and code for this feature.

- Added Alzabo::Runtime::Row->schema method.  Suggested by Ilya
  Martynov.

- Made it possible to use Storable to freeze and thaw any type of row
  object.  Previously, this would have worked but would have
  serialized basically every single Alzabo object in memory (whee!).
  Patch by Ilya Martynov.

- Make Alzabo::Schema->run_in_transaction preserve scalar/array
  context and return whatever was returned by the wrapped code.

BUG FIXES:

- Did some review and cleanup of the exception handling code.  There
  were some places where exceptions were being handled in an unsafe
  manner as well as some spots where exception objects should have
  been thrown that were just using die.

- Ignore failure to rollback for MySQL when not using transactional
  table.

- Alzabo was not handling the BETWEEN operator in where clauses
  properly.  Patch by Eric Hillman.

- Passing in something like this to rows_where:

    ( where => [ $col_foo, '=', 1,
                 $col_bar, '=', 2 ] )

  worked when it shouldn't.

- Trying to do a select that involved a group by and a limit was not
  being allowed.

INCOMPATIBILITIES:

- Got rid of the post_select_hash hook and combined it with
  post_select, which now receives a hash reference.

---------------------------------------------------------------------------

0.58 Oct 18, 2001

ENHANCEMENTS:

- Added new insert_hooks, update_hooks, select_hooks, and delete_hooks
  options to Alzabo::MethodMaker.  Suggested by Ilya Martynov.

- Moved all the important document for the object caching system into
  Alzabo::ObjectCache, including the import options for all of the
  various modules.

- Added Alzabo::ObjectCache::Sync::RDBMS &
  Alzabo::ObjectCache::Store::RDBMS.  The former finally allows
  synchronization of multiple processes across multiple machines!

- Add Alzabo::Schema->has_table and Alzabo::Table->has_column methods.

- Make BYTEA a legal column type for postgres.  This is treated as a
  blob type.

BUG FIXES:

- The way cardinality and dependency was being represented in the
  schema graphs was sometimes backward and sometimes just broken.

- Fixed Alzabo::ObjectCache::Store::BerkeleyDB->clear, which was not
  actually doing anything.  Added tests that catch this.

- The lookup_tables option, which was deprecated in 0.57, was not
  being allowed at all.

- Calls to select_hash on cached rows were not going through the cache
  checking routines, possibly returning expired data.  Added tests for
  this.

- Eliminate race condition in Alzabo::ObjectCache::Sync::BerkeleyDB.

- The Alzabo::Runtime::Row->rows_by_foreign_key method wasn't doing
  quite what it said.  In cases where there was a 1..1 or n..1
  relationship to columns that were not the table's primary key, a
  cursor would be returned instead of a single row.  Reported by Ilya
  Martynov.

- Alzabo::MethoMaker could generate 'subroutine foo redefined'
  warnings .  Reported by Ilya Martynov.

- Fixed clear method for all Alzabo::ObjectCache::Store::* modules.

DEPRECATIONS:

- The insert and update options for Alzabo::MethodMaker have been
  deprecated.  They have been replaced by the new insert_hooks and
  update_hooks options, along with new select_hooks and delete_hooks
  options.

INCOMPATIBILITIES:

- If you specify give the 'all' parameter to MethodMaker, 'insert' and
  'update' are no longer included.

---------------------------------------------------------------------------

0.57 Oct 9, 2001

ENHANCEMENTS:

- When MethodMaker creates 'row_column' methods, these are now get/set
  methods.

- Added new lookup_columns option to MethodMaker (like lookup_tables
  but more flexible).  This replaces the now deprecated lookup_tables
  option.  See DEPRECATIONS and INCOMPATIBILITIES for more details.

- Added the ability to make any storage cache module an LRU.  Simply
  pass an lru_size parameter to Alzabo::ObjectCache when using it and
  the storage module will be an LRU cache.

- Documented Alzabo's referential integrity rules in Alzabo.pm
  (perldoc Alzabo).

- Added section on optimizing memory usage to Alzabo::FAQ.

- Alzabo::Runtime::Schema->join now takes a parameter called
  'distinct'.  This is useful in situations where you are joining
  between several tables but don't want rows back from all of them.
  In that case, it is possible that you could end up getting more
  duplicates than you need.  This parameter can help you eliminate
  those.

- Add the following Alzabo::Schema methods: begin_work, rollback,
  commit, run_in_transaction.

- If you have GraphViz installed the schema creator can now use it to
  show you a graph of your schema.

BUG FIXES:

- Fix handling of binary attribute for MySQL columns.  Generated SQL
  for creating/altering these columns may have been invalid
  previously.

- The rules were not catching an attempt to create a CHAR/VARCHAR
  column with no length (MySQL).

- Fixed bug that caused limit to not work when there was a where
  clause or order_by clause.  Reported by Ilya Martynov.

- Documented row_column option for MethodMaker.

- order_by was ignored when given to the Alzabo::Runtime::Schema->join
  method.  Reported by Martin Ertl.

- When viewing an existing column in the schema creator, the three
  checkboxes at the bottom were always unchecked.

- The test suite has been revamped to use Test::More.  In the process
  some new tests were added and some (gulp) false positives were
  caught.

- The default column value wasn't being escaped in the schema creator.

DEPRECATIONS

- The Alzabo::MethodMaker option 'lookup_tables' has been deprecated.
  Use the new 'lookup_columns' option instead.

INCOMPATIBILITIES:

- Alzabo::ObjectCache::Store modules now expect an object id instead
  of an object for their delete_from_cache method.

- If you specify give the 'all' parameter to MethodMaker,
  'lookup_tables' is no longer included.

---------------------------------------------------------------------------

0.56

Had to become 0.57 cause I was too hasty in uploading to CPAN.  Doh!

---------------------------------------------------------------------------

0.55 Sep 24, 2001

UPGRADE INSTRUCTIONS:

Because of changes to the internal data structures for some objects,
the saved schema files from older versions of Alzabo will no longer
work with this new version.

In the eg/ directory of this distribution, there is a script called
convert.pl that can be used to convert your schemas.

It is _crucial_ that this script be run while you still have your
_current_ version of Alzabo installed.

To repeat, DO NOT INSTALL THE NEWEST VERSION OF Alzabo BEFORE RUNNING
THIS SCRIPT!

Now that we've got that straightened out...

What this script does is read an existing schema and generate code
that you can run after installing the new version of Alzabo.  This
code will recreate your schema from scratch.

It should be noted that this script _will_ reverse the cardinalities
of the relationships in your schema.  See the entries in BUG FIXES
about this.

If you don't like this and want it the old broken way, you can run the
reverse_cardinality.pl script in the eg/ directory on your schemas.
However, you can only do this _after_ installing this new version of
Alzabo.

So the steps you should take are:

1. Backup all of your schema files (by default, these are stored under
   /usr/local/alzabo).

2. Run convert.pl against each schema you have created by doing:

     perl convert.pl <schema name>

   This will create a file named <schema name>_schema.pl

3. After doing this for _all_ of your schemas, install this version
   Alzabo.

4. Simply run each file created by the convert.pl script.  This will
   overwrite the old schema files.

If you are creating your schemas via a script, then you can use the
code generated by convert.pl to replace the code that does this.  Do
note that the cardinalities will be reversed in the generated code.
Those who are doing this will notice that the generated code seems to
contain everything twice.  This has to do with how Alzabo keeps track
of changes from one generation of a schema to the next.  Simply use
the code up to right before the generated code contains the comment
"Previous generation of schema".

ENHANCEMENTS:

- Greatly improved the flexibility of the join and *_outer_join
  methods for the schema class.  It is now possible to construct
  arbitrary joins between any set of tables in any manner.

- Eliminate use of transactions where not needed and shorten their
  length in other places.  Also make sure failed commit triggers a
  rollback.

- Get rid of silly min/max language in favor of cardinality and
  dependencies.

BUG FIXES:

- Fixed a problem with syncing after the Unix time rollover to 10
  digits.

- Alzabo::ForeignKey->is_many_to_one always returned false.

- Alzabo::MethodMaker was interpreting foreign key cardinality
  incorrectly (backwards).  This meant it was treating one-to-many
  relationships as many-to-one.  Reported by Martin Ertl.

  NOTE: This fix will break code that depended on this behavior.  See
  the UPGRADE INSTRUCTIONS above.

- This was also broken in Alzabo::Create::Schema->add_relation.  I
  took this opportunity to rewrite the code get rid of the use of
  min_max_* and replace it with cardinality and dependency, which is
  easier to understand.

  NOTE: This fix will break old code that created schemas
  programmatically.  See the UPGRADE INSTRUCTIONS above.

DEPRECATIONS:

- The Alzabo::Runtime::RowCursor->next_row,
  Alzabo::Runtime::JoinCursor->next_rows, and
  Alzabo::Runtime::OuterJoinCursor->next_rows methods have all been
  deprecated.  Instead, simply use the ->next method for all of them.

INCOMPATIBILITIES:

- The Alzabo::Column->null and Alzabo::Create::Column->set_null
  methods (deprecated in 0.20) are gone.  Use ->nullable and
  ->set_nullable instead.

---------------------------------------------------------------------------

0.51 Aug 29, 2001

BUG FIXES:

- Accidentally broke foreign key display for schema creation interface
  in 0.50. -- In retrospect, the bug was fixing this.  Oh well, live
  and learn.

ENHANCEMENTS:

- Add ->handle method to Alzabo::Driver class, which lets you set and
  get the current database handle.  Suggested by Ilya Martynov.

---------------------------------------------------------------------------

0.50 Aug 16, 2001

ENHANCEMENTS:

- There is now support for left and right outer joins.  The interface
  to this may change a bit in future releases.

- Added the following methods to foreign key objects:
  from_is_dependent, to_is_dependent, is_one_to_one, is_one_to_many,
  is_many_to_one.

- Improved and fixed the Alzabo::MethodMaker documentation.

DEPRECATIONS:

- In some future release all references to the concept 'min_max_from'
  and 'min_max_to' will go away.  Instead, relationships will be
  described by their cardinality and dependencies.  This was changed
  in the schema creation interface a while ago but the APIs have not
  yet completely switched over (there are accessors for the new way,
  but the set methods still use the old concepts).  I'll make sure
  that there is a time when using these methods issues a warning about
  their deprecation.

BUG FIXES:

- Fix pod merging, which broke a while back (this merges superclass
  documentation into subclasses for things like
  Alzabo::Runtime::Table).

- The code was accidentally serializing a DBI handle, which generates
  lots of useless warnings.  This wasn't affecting Alzabo's operations
  as it never attempted to use the thawed handle.

- Fix handling of ENUM and SET column types for MySQL.  These were not
  being allowed through properly.

- Attempting to insert a value into a column that was related to a
  non-primary key column were not allowed if the value being inserted
  did not match the related column in the other table, even when the
  columns were not dependent on each other.  Now this is only
  disallowed when the foreign key is a primary key in its own table.

---------------------------------------------------------------------------

0.49 Jul 18, 2001

BUG FIXES:

- Found out even more missing files from the MANIFEST (all related to
  the schema creation interface).  Fortunately, I just discovered
  Perl's "make distcheck" so this shouldn't happen in the future.

- One link each in the schema creator and data browser were using a
  hard-coded .mhtml extension instead of calling
  Alzabo::Config::mason_extension().  Reported by Barry Hoggard.

---------------------------------------------------------------------------

0.48 Jul 17, 2001

BUG FIXES:

- I was missing yet another file from the MANIFEST.  Thanks to Barry
  Hoggard for helping me out with this.

- Fix a bug in the test number for 03-runtime.t.

---------------------------------------------------------------------------

0.47 Jul 17, 2001

ENHANCEMENTS:

- Make several of the config values settable via the Alzabo::Config
  module.  Suggested by Jared Rhine.

- Transactions should now work under MySQL.  Whether it does anything
  or not depends on the table type you are using.  This needs testing
  though.

BUG FIXES:

- Make sure that index names are not too long.

- Added a missing file to the MANIFEST.  0.46 was missing a needed
  file from the tarball.

---------------------------------------------------------------------------

0.46 Jul 2, 2001

ENHANCEMENTS:

- Column types are now canonized to be all upper case.  When multiple
  keywords specify the same type ('INT' and 'INTEGER', for example),
  one will be chosen.  This improves the quality of the reverse
  engineering and the usability of the schema creation interface.

- You can now use SQL functions pretty much anywhere you would want
  (in inserts, updates, where clauses, etc).  See the "Using SQL
  Functions" section in the Alzabo.pm docs for more details.

- As a corollary to the above, the Alzabo::Runtime::Table->function
  method has been created to replace the old
  Alzabo::Runtime::Table->func method.  This new method takes
  advantage of the new system for using SQL functions and is simpler
  and more flexible.  It allows you to perform all sorts of aggregate
  selects.

- Added the Alzabo::Runtime::Row->select_hash method.  Requested by
  Dana Powers.

DEPRECATIONS:

- The Alzabo::Runtime::Table->func method has been deprecated.

BUG FIXES:

- When adding an AUTO_INCREMENT column to an existing MySQL table, the
  SQL generated would cause an error.  This has been fixed.  However,
  if the table already has more than row then chances are this still
  won't work (because MySQL does not try to generate needed unique
  values for the column when it is added).

---------------------------------------------------------------------------

0.45 Jun 6, 2001

INCOMPATIBILITIES:

- The 'dbm_file' parameter given when loading a syncing module that
  used DBM files (such as Alzabo::ObjectCache::Sync::SDBM_File) has
  been changed to 'sync_dbm_file', because this release includes a new
  cache storage module that uses DBM files as well.

- The schema creator now requires HTTP::BrowserDetect.

- Fix what was arguably a bug in the caching/syncing code.
  Previously, one process could update a row and another process could
  then update that same row.  Now the second process will throw an
  exception.

BUG FIXES:

- Accidentally left debugging turned on in Alzabo::Exceptions.

- The schema creator did not allow you to remove a length or precision
  setting for a column once it had been made.

- Require a length for CHAR and VARCHAR columns with MySQL.

- Add error on setting precision for any column that doesn't allow
  them with MySQL.

- The interaction of caching rows and Alzabo::MethodMaker was not
  right.  Basically, it was determined at compile time whether or not
  to use the cached row class but this needs to be determined at run
  time.  This has been fixed.

- Using the Alzabo::Runtime::Row->rows_by_foreign_key method would
  fail when the column in one table did not have the same name as a
  column in the other table.  Reported by Michael Graham (along with a
  correct diagnosis, thanks!).

- Don't specify a database name when creating or dropping a database.
  Reported and patched by Dana Powers.

ENHANCEMENTS:

- Rules violations error messages (bad table name, for example) in the
  schema creator are now handled in a much friendlier manner.  Instead
  of the big error dump exception page it returns you to the page you
  submitted from with an error message.

- Add Alzabo::Create::Column->alter method which allows you to change
  the column type, length, and precision all at once.  This is
  necessary because some of the column type validation code will
  insist that a column have a length setting.  If you try to change
  them in two separate operations it will throw an exception.

- Add Alzabo::ObjectCache::Store::Null - This allows you to use any
  multi-process syncing module without using up the memory that
  Alzabo::ObjectCache::Store::Memory uses.

- Add Alzabo::ObjectCache::Store::BerkeleyDB - I'm not sure if storing
  in a db file is really a performance win (vs. null storage) because
  of the work needed to freeze & thaw the row objects.  Benchmarks are
  needed.

- Add support for fulltext indexes (MySQL).

- Don't show fulltext or column prefix options when creating indexes
  for databases that don't support these features.

- Use cardinality & dependency language for relations.

- Add some style to the schema creator (via stylesheets).  It looks a
  little better now.

---------------------------------------------------------------------------

0.44 May 4, 2001

BUG FIXES:

- Bug fix in Alzabo::Runtime::Table->set_prefetch.  Reported by Bob
  Gustafson.

- Don't try to make directories when running Makefile.PL.  Save it for
  later after user does 'make install'.

- Fix handling of geometric types in Postgres (they were all being
  rejected as invalid).

- Drop columns from a table before adding new ones.  Sometimes this
  makes a difference.  For example, if you are using MySQL and drop an
  existing AUTO_INCREMENT column and add a new one that is also
  AUTO_INCREMENT.

- Only allow one sequenced column per table when using MySQL.

- Doc fixes.  Thanks to Ron Savage for pointing me towards some of
  these.

- Fix a bug with the schema creator.  If you attempted to make a
  change to a column with an extended type and you did not change the
  type, an error occurred.

ENHANCEMENTS:

- Schema creator now shows you a list of possible column types instead
  of having you type it in.  However, for complex types like MySQL's
  ENUM or Postgres' POLYGON there is a text box to type it in.

---------------------------------------------------------------------------

0.43 Apr 25, 2001

ENHANCEMENTS:

- Allow passing of port when executing SQL from schema creator.

- Confirm schema deletion in schema creator.

BUG FIXES:

- Quick hack to fix a problem with Alzabo::MethodMaker when using
  caching.  However, this requires that the caching modules be loaded
  first, before Alzabo::MethodMaker.  A more palatable fix will be in
  a future release.

- Fix a problem with prefetching rows that caused row objects to
  contain undefined values for certain columns.  This only happened if
  you were prefetching one column.

- Fix another problem that left the schema creator still broken.

---------------------------------------------------------------------------

0.42 Apr 25, 2001

BUG FIXES:

- The schema creator was broken (for lack of quotes around one string)

- Remove 255 char limit on prefix length (this needs more research).

---------------------------------------------------------------------------

0.41 Apr 24, 2001

BUG FIXES:

- 0.40 was missing a file in the distro
  (lib/Alzabo/ObjectCache/Sync/DBM.pm).

---------------------------------------------------------------------------

0.40 Apr 24, 2001

INCOMPATIBILITIES:

The classes in the ObjectCache hierarchy have been reorganized.  The
renaming is as follows:

  Alzabo::ObjectCache::MemoryStore => Alzabo::ObjectCache::Store::Memory
  Alzabo::ObjectCache::DBMSync     => Alzabo::ObjectCache::Sync::DB_File
  Alzabo::ObjectCache::IPCSync     => Alzabo::ObjectCache::Sync::IPC.pm
  Alzabo::ObjectCache::NullSync    => Alzabo::ObjectCache::Sync::Null.pm

ENHANCEMENTS:

- Document order by clauses for joins.

- Document limit clauses for joins and single table selects.

- Expand options for where clauses to allow 'OR' conditionals as well
  as subgroupings of conditional clauses.

- If you set prefetch columns for a table, these are now fetched along
  with other data for the table in a cursor, reducing the number of
  database SELECTs being done.

- Added Alzabo::Create::Schema->clone method.  This allows you to
  clone a schema object (except for the name, which must be changed as
  part of the cloning process).

- Using the profiler, I have improved some of the hot spots in the
  code.  I am not sure how noticeable these improvements are but I
  plan to do a lot more of this type of work in the future.

- Added the Alzabo::ObjectCache::Sync::BerkeleyDB and
  Alzabo::ObjectCache::Sync::SDBM_File modules.  These modules are
  much faster than the old DBMSync or IPCSync modules and actually
  appear to be faster than not syncing at all.  The NullSync (now
  Sync::Null) module is still faster than all of them, however.

BUG FIXES:

- Reversing engineering a MySQL schema with ENUM or SET columns may
  have caused an error if the values for the enum/set contained
  spaces.

- A bug in the schema creation interface made it impossible to create
  an index without a prefix.  Reported by Sam Horrocks.

- When dropping a table in Postgres, the sequences for its columns (if
  any), need to be dropped as well.  Adapted from a patch submitted by
  Sam Horrocks.

- The modules needed by the schema creator and data browser are now
  used by the components.  However, it is still better to load them at
  server startup in order to maximize shared memory.

- Calling the object cache's clear method did not work when using the
  IPCSync or NullSync modules.

- Reverse engineering a Postgres database was choking on char(n)
  columns, which are converted internally by Postgres into bpchar(n)
  columns.  This is now fixed (by converting them back during reverse
  engineering).

- Reject column prefixes > 255 with MySQL.  I hesitate to call this a
  bug fix since this appears to be undocumented in the MySQL docs.

- Using the DBMSync module in an environment which started as one user
  and then became another (like Apache) may have caused permiission
  problems with the dbm file.  This has been fixed.

MISC:

- Require DBD::Pg 0.97 (the latest version as of this writing) as it
  fixes some bugs in earlier versions.

ARCHITECTURE:

- Split up Row object into Alzabo::Runtime::Row (base class for
  standard uncached row) and Alzabo::Runtime::CachedRow (subclass for
  rows that have to interact with a cache).  This simplifies the code,
  particulary in terms of how it interacts with the caching system.

- Made Alzabo::Runtime::Row->get_data a private method.  This served
  no purpose for end users anyway.

---------------------------------------------------------------------------

0.36 Mar 20, 2001

- Addition of Params::Validate broke several methods:
-- The Alzabo::Schema->tables method was broken when trying to
   retrieve a subset of all the tables.
-- The Alzabo::Create::Schema->move_table method was broken (thus
   breaking the ability to add a table at a specified place in the table
   order).
-- Same problem for Alzabo::Create::Table->move_column.

- Added to the test suite to catch all this in the future.

- Attempting to dynamically generate component paths in the Mason
  component was a bad idea, particularly since it was unnecessary
  because I can find the component by doing '../common/foo'.  Thanks
  to Bob Gustafson for suggesting this.

- Fix bug in Postgres rules that didn't allow length for CHAR columns.

- Fixed problems running multi-process tests with Postgres.

---------------------------------------------------------------------------

0.35 Mar 18, 2001

- Add ability to specify port parameter when connecting to DB for
  reverse engineering/data browser.

- Fix support for host param in data browser.

- Added a new Alzabo/FAQ.pod file.  Its pretty skimpy but hopefully it
  will become more useful over time.

- If your Mason component root was under your document then the links
  to return to the top levels of the schema creator and data browser
  were broken.  Note: if your component root is entirely outside your
  document root then things may not work at all.

- Add support for extra MySQL connection params (like
  mysql_default_file).  See the Alzabo::Driver::MySQL docs for more
  details.

- Add support for Postgres connect params 'options' and 'tty'.

- Alzabo::Create::Schema->reverse_engineer was not passing the 'port'
  parameter to the driver when attempting to make a driver.

- Attempting to pass in the port parameter to a connection would have
  generated a bad DSN due to a type in the code.

- Started using Params::Validate so I can be even stricter about
  argument checking.

- Fix bug introduced in 0.33.  Changing a column's type always removed
  any length and precision setting for the column.  Now it is only
  removed if the new column type does not allow a length or precision
  setting.

- Fix some warnings in the Makefile.PL code.  Also require Pod::Man >=
  1.14 to handle =head3 and =head4 directives.

- The Postgres code did not allow the ABSTIME, MACADDR, or RELTIME
  column types.  These have been added.  Thanks to Bob Gustafson for
  helping me find this problem.

- The Alzabo::Create::Schema->reverse_engineer method was not doing
  anything with a host parameter.  Reported by Aaron Johnson.

- Fix bug in Alzabo::ObjectCache docs.  Reported by Robin Berjon.

- Include a first version of the quick method reference suggested by
  Robin Berjon.  This Alzabo::QuickRef.  The HTML version is
  table-ized and spiffed up a bit from the POD version.

---------------------------------------------------------------------------

0.34 Feb 26, 2001

- If you were trying to run the tests on a system without MySQL
  installed, or without the DB_File or IPC::Shareable modules, you saw
  lots of test failures, even if you said you did not plan to use the
  parts of Alzabo that required these.  This has been fixed.  I can
  now run the tests successfully using a Perl with only DBD::Pg and
  DBI installed and it will skip any tests that it can't run.

- Fixed another caching bug related to objects that were deleted and
  then another row was inserted with the same primary key.  Note to
  self: premature optimization is the root of all evil.

---------------------------------------------------------------------------

0.33 Feb 21, 2001

- The linking table methods generated by Alzabo::MethodMaker were
  broken.  Fixed this.

- Changed how order by clauses can be passed to select operations.
  Also changed the docs, which were way out of sync with the changes
  in this area.

- Attempting to update more than one value at once was broken.  Fixed
  this.

- Added Alzabo::Runtime::Table->func method to allow arbitrary column
  aggregate functions like MAX, MIN, AVG, etc.

- Fixed schema creator bug.  It was not possible to change a column's
  NULLability after it was created.

- When changing a column's type, Alzabo now removes any column
  attributes that are not valid for that column.  In addition, if the
  existing length and precision parameters are not valid, they will be
  set to undef.

- Fixed the code to get rid of weird error messages that came from DBI
  with Perl 5.6.0+ when the Alzabo::Create::Schema->create or
  Alzabo::Create::Schema->reverse_engineer methods were called.  For
  the curious, this has to do with the DBI object passing through
  Storable::dclone.

---------------------------------------------------------------------------

0.32 Feb 7, 2001

- Forgot to include data browser files in MANIFEST.  Caused weirdness
  if you said you wanted it when asked during install.  Reported by
  Remi Cohen-Scali.

---------------------------------------------------------------------------

0.31 Feb 5, 2001

Bug fixes only

- Fix bugs in Alzabo::MethodMaker.  The insert, update, lookup_table,
  and self_relation (parent portion only) were broken.

- A bug in the SQL making code was causing some queries to appear as
  if they failed when they didn't.

---------------------------------------------------------------------------

0.30 Feb 4, 2001

- The convert.pl script in eg/ has been updated to handle the new
  release.  IMPORTANT: I forgot to include a mention of this in the
  last release but you need to run the script _before_ installing a
  new version of Alzabo.

- Many improvements and updates to Alzabo::MethodMaker.  Highlights
  include fixing a bug that prevented the insert and update methods
  from being created, a new callback system that allows you to specify
  all the method names to be generated, and a new 'self_relations'
  option for tables that have parent/child relationships with
  themself.

- Fix handling of NULL columns for inserts and updates.  Now, Alzabo
  only throws an exception if the column is not nullable and has no
  default.  If it has a default and is specified as NULL then it will
  not be included in the INSERT clause (in which case the RDBMS should
  insert the default value itself).

- Fix bugs in Postgres reverse engineering.  Defaults were not handled
  properly, nor were numeric column type length and precision.

- The schema creator and data browser now allow you to enter the host
  for database connections where needed.

- Foreign keys can now span multiple columns.  This means you can have
  a relation from foo.foo_id and foo.index_id to bar.foo_id and
  bar.index_id.  This required some changes to the interface for the
  foreign key objects.  Notably, the Alzabo::ForeignKey->column_from
  and Alzabo::ForeignKey->column_to methods are now
  Alzabo::ForeignKey->columns_from and Alzabo::ForeignKey->columns_to.
  In addition, the parameters given to the
  Alzabo::Create::Schema->add_relation have changed.

- Major changes to caching architecture.  The caching code has been
  split up.  There is now a 'storing' class, which holds onto the
  objects (the cache).  Then there is a 'sync' class.  This class
  handles expiration and deletion tracking.  These two classes can be
  mixed and matched.  Right now there is only one storage class (which
  stores the objects in memory).  There are 3 syncing classes.  One,
  NullSync, doesn't actually sync objects.  It does track deletions,
  but not expirations.  The others, IPCSync and DBMSync, use IPC or
  DBM files to track expiration and deletion of objects.

- Doing this work highlighted some bugs in the caching/syncing code.
  One oversight was that if you deleted an object and then inserted
  another row with the exact same primary key, the cache continued to
  think the object was deleted.  Other bugs also surfaced.  These have
  been fixed and the test suite has been updated so caching should be
  stable (if not, I'll have to cry).

- When viewing an existing column in the schema creator, defaults,
  lengths, and precision of 0 were not being shown.

- Alzabo::Runtime::Table->row_count can now take a where clause.

- Fix bugs in Alzabo::Create::Table.  This was causing problems with
  indexes when the table name was changed.

- Fixed a bug in Alzabo::Util that caused the test cases to fail if
  Alzabo hadn't been previously installed.  Reported by Robert Goff.

- The SQLMaker class is now smarter about not letting you make bad
  SQL.  For example, if you try to make a WHERE clause with tables not
  mentioned in the FROM clause, it will throw an exception.  This will
  hopefully help catch logic errors in your code a bit sooner.

- Removed use of prepare_cached in Alzabo::Driver.  This has the
  potential to cause some strange errors under Alzabo.  Because of the
  way Alzabo works, it is possible to have a Cursor object holding
  onto a statement handle that needs to be used elsewhere (by a row
  object, for example).  It is safer to let a new statement handle be
  created in this case.

INCOMPATIBILITIES

- See the note above about the changes required to support
  multi-column foreign keys.

- Because of the aforementioned changes to the caching architecture,
  caching just does not work the way it used to.

  1. By default, there is no caching at all.

  2. To get the old behavior, which defaulted to an in-process memory
  cache with no inter-process syncing (meaning deletes are tracked but
  there is no such thing as expiration), you can do this in your code:

    use Alzabo::ObjectCache( store => 'Alzabo::ObjectCache::MemoryStore',
                             sync  => 'Alzabo::ObjectCache::NullSync' );

  or just:

    use Alzabo::ObjectCache;  # the above modules are the defaults

  3. To get the behavior of the old Alzabo::ObjectCacheIPC module, do:

    use Alzabo::ObjectCache( store => 'Alzabo::ObjectCache::MemoryStore',
                             sync  => 'Alzabo::ObjectCache::IPCSync' );

  However, the new DBMSync module will probably scale better, and
  performance should be about the same for smaller applications.  To
  use it, do:

    use Alzabo::ObjectCache( store => 'Alzabo::ObjectCache::MemoryStore',
                             sync  => 'Alzabo::ObjectCache::DBMSync' );

  4. If you run without any caching at all then the
  Alzabo::Runtime::Row class's behavior has changed somewhat.  In
  particular, selects or updates against a deleted object will always
  throw an Alzabo::Exception::NoSuchRow exception.  Before, the
  behavior wasn't very well defined.

  Please read the section on clearing the cache in the
  Alzabo::ObjectCache module, as this is an important concept.  By
  default, the caching and syncing modules will just grow unchecked.
  You need to clear at the appropriate points (usually your
  application's entry points) in order to keep them under control.

---------------------------------------------------------------------------

0.20 Jan 9, 2001

- Preliminary Postgres support.  There is no support yet for
  constraints or foreign keys when reverse engineering or making SQL.
  There is also no support for large objects (I'm hoping that 7.1 will
  be released soon so I won't have to think about this).  Otherwise,
  the support is about at the same level as MySQL support, though less
  mature.

- Added Alzabo::MethodMaker module.  This can be used to auto-generate
  useful methods for your schema/table/row objects based on the
  properties of your objects themselves.

- Reworking/expanding/clarifying/editing of the docs.

- Add order_by and limit options whenever creating a cursor.

- Method documentation POD from the Alzabo::* modules is merged into
  the relevant Alzabo::Create::* and Alzabo::Runtime::* modules during
  install.  This should make it easier to find what you need since the
  average user will only need to look at a few modules in
  Alzabo::Runtime::*.

- Reworked exceptions so they are all now
  Alzabo::Exception::Something.

- Added default as a column attribute (thus there are now
  Alzabo::Column->default and Alzabo::Create::Column->set_default
  methods).

- Added length & precision attributes for columns.  Both are set
  through the Alzabo::Create::Column->set_length method.

- This release includes a script in eg/ called convert.pl to convert
  older schemas.

- Alzabo::Schema->tables & Alzabo::Table->columns now take an optional
  list of tables/columns as an argument and return a list of matching
  objects.

- Added Alzabo::Column->has_attribute method.

- The data browser has actually lost some functionality (the
  filtering).  Making this more powerful is a fairly low priority at
  the moment.

- Fix bugs where extra params passed to Alzabo::Runtime::Table->insert
  were not making it to the Alzabo::Runtime::Row->new method.

- Fix for Alzabo::Runtime::Table->set_prefetch method.

- Fixed bug in handling of deleted object in Alzabo::ObjectCacheIPC
  (they were never reported as deleted).

- Fix bug that caused schema to get bigger every time it was saved.

- Finally switched to regular hashes for objects.

- Added Alzabo::SQLMaker classes to handle generating SQL in a
  cross-platform compatible way.

DEPRECATIONS:

- Parameters for Alzabo::Create::Column->new: 'null' parameter is now
  'nullable'.  The use of the parameter 'null' is deprecated.

- Alzabo::Column->null & Alzabo::Column->set_null methods are now
  Alzabo::Column->nullable & Alzabo::Column->set_nullable.  The old
  methods are deprecated.

- Alzabo::Create::ForeignKey->new no longer requires table_from &
  table_to params (it took me this long to realize I can get that from
  the column passed in.  doh!)

INCOMPATIBILITIES:

- Alzabo::Runtime::Table->rows_where parameters have changed.  The
  from parameter has been removed (use the
  Alzabo::Runtime::Schema->join method instead).  The where parameter
  expects something different now.

- Alzabo::Runtime::Table->rows_by_where_clause method has been
  removed.

- Alzabo::Runtime::Schema->join method's where parameter expects
  something different.

---------------------------------------------------------------------------

0.10_5 Oct 10, 2000

- You can now specify a database name to be used for testing.  The
  default is 'test_alzabo'.  This a good default for MySQL, at least.
  Thanks to Randal Schwartz for the help.

- Make sure test file cleanup is done _before_ attempting tests so
  that files from a test previously aborted are cleaned up (and no
  errors are generated.  Thanks to Randal Schwartz for the bug report.

- Doesn't fail on install for Mason components if no Mason component
  extension was given.  Thanks _again_ to Randal for working with me
  on this in IRC late at night.

---------------------------------------------------------------------------

0.10_4 Oct 10, 2000

- Fix Makefile.PL bug

- Auto select a column when adding a relation (if there is a logical
  one to select).

---------------------------------------------------------------------------

0.10_3

- Fix bug with deleting foreign key objects from tables.

---------------------------------------------------------------------------

0.10

  **FIRST BETA VERSION**

- Doc bug fixes in Alzabo::Runtime::Schema.

- Fix fact that Alzabo::Runtime::Row rows_by_foreign_key method could
  return either a Row _or_ RowCursor object.  Now it always returns a
  cursor object.

- Fix fact that no_cache parameter was not propagated through the
  RowCursor object to the rows it created.

- Add all all_rows method to Alzabo::Runtime::RowCursor.

- Add ability to reset instantiation flag in schema creation
  interface.

- Updated INSTALL to mention how to get the schema creator and data
  browser working.

- Finally make creating relations between tables _without_ specifying
  the columns work.  This does some, IMHO, pretty cool DWIMmery.

- Added primary_key param to Alzabo::Runtime::Table make_column
  method.

- Added set_host and host methods to Alzabo::Runtime::Schema.

- Added drop method to Alzabo::Create::Schema and necessary support in
  driver modules.

- Changed 'id' param to 'pk' for Alzabo::Runtime::Table row_by_pk
  method.  'id' still works, for now, but is deprecated.

- Fix problem where an insert could generate a referential integrity
  exception but still end up in the database.  Note, without
  transactions (in MySQL, for example), there's no way to make the all
  of the referential integrity code work correctly 100% of the time.

- Added new class Alzabo::ObjectCache to make sure that objects stay
  in sync after referential integrity operations happen.  This is now
  the default caching class.  Please make sure to read the docs for
  this new module, particularly if you're running Alzabo under a
  persistent environment where this module can be quite the memory hog
  if not used properly (clear the cache!).

- Fixed breakage in maintenance of referential integrity caused by
  switch to cursors (and me not fixing all the code that expected row
  objects).

- Added Alzabo::Runtime::Cursor base class.

- Added join method to Alzabo::Runtime::Schema.  *EXPERIMENTAL*

- Added Alzabo::Runtime::JoinCursor class.  *EXPERIMENTAL*

- Began conversion of all classes from pseudohash to hash.

- Both schema creator and data browser now respect user choice of
  component extension.

---------------------------------------------------------------------------

0.09

- MAJOR CHANGE: All the Alzabo::Runtime::Row methods that used to
  return lists of rows now return the new Alzabo::Runtime::RowCursor
  object.  This change is a major speed and memory optimization.  It
  does, however, break the old interface.  But its worth it.

- Set autohandlers for schema maker and data browser so that they
  won't inherit from other autohandlers higher up the directory tree.

- Fix bug in Alzabo::Driver which made it so that the one_row_hash
  method always returned a hash with keys.  This caused spurious row
  object to be created in the Alzabo::Runtime::Row class.

- Fix bug in Alzabo::Table::rows_where method where it wasn't handling
  the construct $table->rows_where( where => { foo => undef } )
  properly.

---------------------------------------------------------------------------

0.08

- Lazy column evaluation had made it possible to create an
  Alzabo::Runtime::Row object that did not correspond to any data in
  the database if its table object did specify any rows to prefetch.
  This would have only been discovered later by calling the select
  method on a non-primary key column.  This hole was plugged.

- As a corollary to the above change methods in Alzabo::Runtime::Table
  that produce rows now always return an empty list or undef when the
  rows cannot be made because the specified primary key doesn't exist.
  Previously, the rows_by_where_clause method did this while others
  would cause an exception either during the object creation or later,
  depending upon the situation described above.

- GENERAL NOTE: I probably used exceptions too much, as in the above
  case.  I will probably be making a few more changes like this in the
  future.

- Bug fix in Alzabo::RDBMSRules when making SQL diffs.  Forgot to
  account for new foreign key method names.

- Bug fix related to MySQL auto_increment column and
  Alzabo::Runtime::Table insert method.  Basically, you couldn't
  insert into a table and use its auto_increment feature.

- Alzabo::Table::set_prefetch now makes sure that primary key columns
  are not included.  It simply ignores them but they will not be
  returned by the prefetch method.

- fix bug where some row retrieval methods would fail if not given a
  'bind' parameter.

- Doc bug fix.  Docs for Alzabo::Runtime::Table listed group_by_column
  as simply group.  Of course, this probably only needs to be used by
  Alzabo::Runtime::Row anyway.

- Added Alzabo::Runtime::Table rows_where method.

- Added Alzabo::Runtime::Table all_rows method.

- Documented 'bind' parameter for Alzabo::Runtime::Table
  rows_by_where_clause method.

---------------------------------------------------------------------------

0.07

- Fixed major bugs in Alzabo::Runtime::Table::insert method.

- Fixed bug in Alzabo::Runtime::Row::delete method related to API
  change in 0.06

- Reduce amount of work done in Alzabo::Runtime::Row when referential
  integrity maintenance is set to false.

- Added new method to Alzabo::Runtime::Row: rows_by_foreign_key.  A
  row can now fetch the rows that are related to it automatically.

- Made all Alzabo::Table foreign key object returning methods
  list/scalar context sensitive.  This is useful when you know that
  there is only one foreign key that matches what you are looking for.

---------------------------------------------------------------------------

0.06

- change return value from Alzabo::Index id method to be something
  that can be an actual index name.  This is a bug fix as previously
  index SQL was not valid (at least not for MySQL).

- cosmetic fixes in schema creator

- moved exception component to common mason files so its shared by
  schema creator and data browser.

- added Index attribute of unique (so we can make unique indexes).

- made SQL making code for MySQL aware of this.

- added ability to set this to schema creator.

- added ability to specify column order in an index in schema creator.

- made it possible for a table to have more than one foreign from a
  given column.  documented how this changes API in Alzbo::Table.

- API: The Alzabo::Table foreign_keys() method name has been changed
  to all_foreign_keys().  The foreign_key method (which returns keys
  by table to and column from) is now the foreign_keys() method
  because it can return more than one object.

- change schema creator, Alzabo::Create::Schema module, and
  03/create.t test to handle this properly.

- added ability to move columns and tables to arbitrary new locations
  after they've been created (without the arrows).

---------------------------------------------------------------------------

0.05

- bug fix for Alzabo::Runtime::Row calling wrong method from schema
  object

- got rid of the locking stuff in the MySQL driver.  Since its not
  possible to have more than 1 lock at a time with the GET_LOCK
  function there's no way to have the right kinds of locks for
  cascading deletes.  It might be possible to do this kind of locking
  via some other mechanism (semaphores, DBM files, whatever, but
  that's a hack for another day.

---------------------------------------------------------------------------

0.04

- Switched to use Tie::IxHash object interface

- fixed stupid bug in Alzabo::RDBMSRules::MySQL

- changed the way Alzabo::ChangeTracker works.  it requires fewer
  method calls to do its job now.

- added set_referential_integrity/referential_integrity methods to
  Alzabo::Runtime::Schema.  The default is to not attempt to maintain
  referential_integrity.

- It should no longer be possible for Alzabo::Runtime::ForeignKey
  objects to create loops when maintaining referential integrity.  It
  also should be a bit more efficient in the register_delete method.
  If no action needs to be taken, it won't loop through all the rows
  in the related table before finding this out.

- fixed data browser bug when putting in a filter on any page that was
  not the first page of results for a table.

- fixed data browser bug in paging with filters.

---------------------------------------------------------------------------

0.03

- Fixed bugs in Alzabo::ObjectCacheIPC so it now works.

- Added lazy column evaluation (see Alzabo::Runtime::Table) docs

- Added Alzabo::DriverStatement and Alzabo::Driver::Exception to Alzabo::Driver

- improved data browser memory efficiency

- minor bug fixes (bad links) in data browser and schema maker

- minor buglet fix in Alzabo::Driver::MySQL

- big fix to how Alzabo::Runtime::Schema is saved from
  Alzabo::Create::Schema.  Previous implementation was accidentally
  saving both the runtime and create versions at once.  The new
  version fixes this.
