=head1 NAME

DBI::Changes - Log of significant changes to the DBI

=cut

=head1 Todo

 I'll be building this list shortly.
 Make ODBC version 3.0 default!
 Add array parameter binding (per new DBI Spec)
 Add row caching/multiple row fetches to speed selects
 Better/more tests on multiple statement handles which ensure the correct number of rows
 Better/more tests on all queries which ensure the correct number of rows
 Better tests on SQLExecDirect/do
 Change default behaviour to use SQLDescribeParam instead of SQL_VARCHAR.

 Keep checking Oracle's ODBC drivers for Windows to fix the Date binding problem

=head1 CHANGES

 See DBD::ODBC POD for more detail.

=head2 DBD::ODBC 0.43

Fix for FoxPro (and potentially other) Drivers!!!!!
Add support for DBI column_info
Fix for binding undef value which comes from dereferencing hash
Fix to make all bound columns word (int) aligned in the buffer.

=head2 DBD::ODBC 0.42

Added patches to the tests to support ActiveState's automated build process.
Fix ping() to try SQLTables for a test, instead of a strange query.  

=head2 DBD::ODBC 0.41

Fixed problem where SQLDescribeParam would fail (probably
bug in ODBC driver).  Now reverts to SQL_VARCHAR if that
happens, instead of failing the query.

Fixed error report when using Oracle's driver.  There is
a known problem.  Left the error on the test, but added
warning indicating it's a known problem.

=head2 DBD::ODBC 0.40

Most significant change is the change in the default binding
type which forces DBD::ODBC to attempt to determine the bind
type if one is not passed.  I decided to make this the default
behavior to make things as simple as possible.

Fixed connection code put in 0.39 to work correctly.

Two minor patches for building, one for Cygwin one
if both iODBC and unixODBC libraries are installed.
Probably need better command line on this, but if 
someone has the problem, please let me know (and 
hopefully send a patch with it).

=head2 DBD::ODBC 0.39
 
 See mytest/longbin.pl for demonstration of inserting and retrieving
 long binary files to/from the db.  Uses MD5 algorithm to verify data.
 Please do some similar test(s) with your database before using it
 in production.  The various bind types are different for each database!

 Finally removed distribution of old iODBC.  See www.iodbc.org or
 www.unixodbc.org for newer/better versions of the ODBC driver
 manager for Unix (and others?). 

 Added ability to force ODBC environment version.
 
 Fix to SQLColAttributes.

 Changes to connect sequence to provide better error
 messages for those using DSN-less connections.

=head2 DBD::ODBC 0.38

 Fixed do function (again) thanks to work by Martin Evans.

=head2 DBD::ODBC 0.37

 Patches for get_info where return type is string.  Patches
 thanks to Steffen Goldner.  Thanks Steffen!

 Patched get_info to NOT attempt to get data for SQL_DRIVER_HSTMT
 and SQL_DRIVER_HDESC as they expect data in and have limited value
 (IMHO).

=head2 Changes in DBD::ODBC 0.37

 Further fixed build for ODBC 2.x drivers.  The new SQLExecDirect
 code had SQLAllocHandle which is a 3.x function, not a 2.x function.
 Sigh.  I should have caught that the first time.  Signed, the Mad-and-
 not-thorough-enough-patcher.

 Additionally, a random core dump occurred in the tests, based upon the
 new SQLExecDirect code.  This has been fixed.
 
 
=head2 Changes in DBD::ODBC 0.36

 Fixed build for ODBC 2.x drivers.  The new SQLExecDirect code
 had SQLFreeHandle which is a 3.x function, not a 2.x function.
 
=head2 Changes in DBD::ODBC 0.35

 Fixed (finally) multiple result sets with differing
 numbers of columns.  The final fix was to call
 SQLFreeStmt(SQL_UNBIND) before repreparing
 the statement for the next query.

 Added more to the multi-statement tests to ensure
 the data retrieved was what was expected.

 Now, DBD::ODBC overrides DBI's do to call SQLExecDirect
 for simple statements (those without parameters).
 Please advise if you run into problems.  Hopefully,
 this will provide some small speed improvement for
 simple "do" statements.  You can also call
 $dbh->func($stmt, ExecDirect).  I'm not sure this has
 great value unless you need to ensure SQLExecDirect
 is being called.  Patches thanks to Merijn Broeren.
 Thanks Merijn!
   
=head2 Changes in DBD::ODBC 0.34
 
 Further revamped tests to attempt to determine if SQLDescribeParam
 will work to handle the binding types.  The t/08bind.t attempts
 to determine if SQLDescribeParam is supported.  note that Oracle's
 ODBC driver under NT doesn't work correctly when binding dates
 using the ODBC date formatting {d } or {ts }.  So, test #3 will
 fail in t/08bind.t

 New support for primary_key_info thanks to patches by Martin Evans.
 New support for catalog, schema, table and table_type in table_info
 thanks to Martin Evans.  Thanks Martin for your work and your
 continuing testing, suggestions and general support!

 Support for upcoming dbi get_info.
 
=head2 Changes in DBD::ODBC 0.33_3

 Revamped tests to include tests for multiple result sets.
 The tests are ODBC driver platform specific and will be skipped
 for drivers which do not support multiple result sets.
 
=head2 Changes in DBD::ODBC 0.33_2

 Finally tested new binding techniques with SQL Server 2000,
 but there is a nice little bug in their MDAC and ODBC
 drivers according to the knowledge base article # Q273813, titled

   "FIX: "Incorrect Syntax near the Keyword 'by' "
   Error Message with Column Names of "C", "CA" or "CAS" (Q273813)

 DBD::ODBC now does not name any of the columns A, B, C, or D
 they are now COL_A, COL_B, COL_C, COL_D.

 *** NOTE: *** I AM STRONGLY CONSIDERING MAKING THE NEW
 BINDING the default for future versions.  I do not believe
 it will break much existing code (if any) as anyone binding
 to non VARCHAR (without the ODBC driver doing a good conversion
 from the VARCHAR) will have a problem.  It may be subtle, however,
 since much code will work, but say, binding dates may not with
 some drivers.
   
 Please comment soon...
   
=head2 Changes in DBD::ODBC 0.33_1

*** WARNING: ***
 
 Changes to the binding code to allow the use of SQLDescribeParam
 to determine if the type of column being bound.  This is
 experimental and activated by setting
 
  $dbh->{odbc_default_bind_type} = 0; # before creating the query...

 Currently the default value of odbc_default_bind_type = SQL_VARCHAR
 which mimicks the current behavior.  If you set
 odbc_default_bind_type to 0, then SQLDescribeParam will be
 called to determine the columen type.  Not ALL databases
 handle this correctly.  For example, Oracle returns
 SQL_VARCHAR for all types and attempts to convert to the
 correct type for us.  However, if you use the ODBC escaped
 date/time format such as: {ts '1998-05-13 00:01:00'} then
 Oracle complains.  If you bind this with a SQL_TIMESTAMP type,
 however, Oracle's ODBC driver will parse the time/date correctly.
 Use at your own risk!

 Fix to dbdimp.c to allow quoted identifiers to begin/end
 with either " or '.
 The following will not be treated as if they have a bind placeholder:
   "isEstimated?"
   '01-JAN-1987 00:00:00'
   'Does anyone insert a ?'

				    
=head2 Changes in DBD::ODBC 0.32

 More SAP patches to Makfile.PL to eliminate the call to Data Sources

 A patch to the test (for SAP and potentially others), to allow
 fallback to SQL_TYPE_DATE in the tests
 
=head2 Changes in DBD::ODBC 0.31

 Added SAP patches to build directly against SAP driver instead of
 driver manager thanks to Flemming Frandsen (thanks!)

 Added support to fix ping for Oracle8.  May break other databases,
 so please report this as soon as possible.  The downside is that
 we need to actually execute the dummy query.
 

=head2 Changes in DBD::ODBC 0.30

 Added ping patch for Solid courtesy of Marko Asplund

 Updated disconnect to rollback if autocommit is not on.
 This should silence some errors when disconnecting.

 Updated SQL_ROWSET_SIZE attribute.  Needed to force it to
 odbc_SQL_ROWSET_SIZE to obey the DBI rules.

 Added odbc_SQL_DRIVER_ODBC_VER, which obtains the version of
 the Driver upon connect.  This internal capture of the version is
 a read-only attributed and is used during array binding of parameters.
 
 Added odbc_ignore_named_placeholders attribute to facilicate
 creating triggers within SAPDB and Oracle, to name two. The
 syntax in these DBs is to allow use of :old and :new to
 access column values before and after updates.  Example:

 $dbh->{odbc_ignore_named_placeholders} = 1; # set it for all future statements
					  # ignores :foo, :new, etc, but not :1 or ?
 $dbh->do("create or replace etc :new.D = sysdate etc");
 

=head2 Changes in DBD::ODBC 0.29

 Cygwin patches from Neil Lunn (untested by me).  Thanks Neil!
 
SQL_ROWSET_SIZE attribute patch from Andrew Brown 
> There are only 2 additional lines allowing for the setting of
> SQL_ROWSET_SIZE as db handle option.
>
> The purpose to my madness is simple. SqlServer (7 anyway) by default
> supports only one select statement at once (using std ODBC cursors).
> According to the SqlServer documentation you can alter the default setting
> of
> three values to force the use of server cursors - in which case multiple
> selects are possible.
>
> The code change allows for:
> $dbh->{SQL_ROWSET_SIZE} = 2;    # Any value > 1
>
> For this very purpose.
>
> The setting of SQL_ROWSET_SIZE only affects the extended fetch command as
> far as I can work out and thus setting this option shouldn't affect
> DBD::ODBC operations directly in any way.
>
> Andrew
>

VMS and other patches from Martin Evans (thanks!)

[1] a fix for Makefile.PL to build DBD::ODBC on OpenVMS.

[2] fix trace message coredumping after SQLDriverConnect

[3] fix call to SQLCancel which fails to pass the statement handle properly.

[4] consume diagnostics after SQLDriverConnect/SQLConnect call or they remain
    until the next error occurs and it then looks confusing (this is due to
    ODBC spec for SQLError). e.g. test 02simple returns a data truncated error
    only now instead of all the informational diags that are left from the
    connect call, like the "database changed", "language changed" messages you
    get from MS SQL Server.

Replaced C++ style comments with C style to support more platforms more easily.

Fixed bug which use the single quote (') instead of a double quote (") for "literal" column names.  This
   helped when having a colon (:) in the column name.

Fixed bug which would cause DBD::ODBC to core-dump (crash) if DBI tracing level was greater than 3.

Fixed problem where ODBC.pm would have "use of uninitialized variable" if calling DBI's type_info.

Fixed problem where ODBC.xs *may* have an overrun when calling SQLDataSources. 

Fixed problem with DBI 1.14, where fprintf was being called instead of PerlIO_printf for debug information

Fixed problem building with unixODBC per patch from Nick Gorham   

Added ability to bind_param_inout() via patches from Jeremy Cooper.  Haven't figured out a good, non-db specific
   way to test.  My current test platform attempts to determine the connected database type via
   ugly hacks and will test, if it thinks it can.  Feel free to patch and send me something...Also, my
   current Oracle ODBC driver fails miserably and dies.

Updated t/02simple.t to not print an error, when there is not one.
   
=head2 Changes in DBD::ODBC 0.28

Added support for SQLSpecialColumns thanks to patch provided by Martin J. Evans [martin@easysoft.com]

Fixed bug introduced in 0.26 which was introduced of SQLMoreResults was not supported by the driver.

=head2 Changes in DBD::ODBC 0.27

Examined patch for ping method to repair problem reported by Chris Bezil.  Thanks Chris!

Added simple test for ping method working which should identify this in the future.

=head2 Changes in DBD::ODBC 0.26

Put in patch for returning only positive rowcounts from dbd_st_execute.  The original patch
was submitted by Jon Smirl and put back in by David Good.  Reasoning seems sound, so I put it
back in.  However, any databases that return negative rowcounts for specific reasons,
will no longer do so.

Put in David Good's patch for multiple result sets.  Thanks David!  See mytest\moreresults.pl for
an example of usage.

Added readme.txt in iodbcsrc explaining an issue there with iODBC 2.50.3 and C<data_sources>.

Put in rudimentary cancel support via SQLCancel.  Call $sth->cencel to utilize.  However, it is largely
untested by me, as I do not have a good sample for this yet.  It may come in handy with threaded
perl, someday or it may work in a signal handler.
   
=head2 Changes in DBD::ODBC 0.25

Added conditional compilation for SQL_WVARCHAR and SQL_WLONGVARCHAR.  If they
are not defined by your driver manager, they will not be compiled in to the code.
If you would like to support these types on some platforms, you may be able to
 #define SQL_WVARCHAR (-9)
 #define SQL_WLONGVARCHAR (-10)

Added more long tests with binding in t\09bind.t.  Note use of bind_param!
 
=head2 Changes in DBD::ODBC 0.24

Fixed Test #13 in 02simple.t.  Would fail, improperly, if there was only one data source defined.

Fixed (hopefully) SQL Server 7 and ntext type "Out of Memory!" errors via patch from Thomas Lowery.  Thanks Thomas!

Added more support for Solid to handle the fact that it does not support data_sources nor SQLDriverConnect.
 Patch supplied by Samuli Karkkainen [skarkkai@woods.iki.fi].  Thanks!  It's untested by me, however.

Added some information from Adam Curtin about a bug in iodbc 2.50.3's data_sources.  See
   iodbcsrc\readme.txt.

Added information in this pod from Stephen Arehart regarding DSNLess connections.

Added fix for sp_prepare/sp_execute bug reported by Paul G. Weiss.

Added some code for handling a hint on disconnect where the user gets an error for not committing.
 
=head2 Changes in DBD::ODBC 0.22

Fixed for threaded perl builds.  Note that this was tested only on Win32, with no threads in use and using DBI 1.13.
Note, for ActiveState/PERL_OBJECT builds, DBI 1.13_01 is required as of 9/8/99.  
If you are using ActiveState's perl, this can be installed by using PPM.


=head2 Changes in DBD::ODBC 0.21

Thanks to all who provided patches!

Added ability to connect to an ODBC source without prior creation of DSN.  See mytest/contest.pl for example with MS Access.
(Also note that you will need documentation for your ODBC driver -- which, sadly, can be difficult to find).

Fixed case sensitivity in tests.

Hopefully fixed test #4 in t/09bind.t.  Updated it to insert the date column and updated it to find the right
type of the column.  However, it doesn't seem to work on my Linux test machine, using the OpenLink drivers 
with MS-SQL Server (6.5).  It complains about binding the date time.  The same test works under Win32 with 
SQL Server 6.5, Oracle 8.0.3 and MS Access 97 ODBC drivers.  Hmmph.

Fixed some binary type issues (patches from Jon Smirl)

Added SQLStatistics, SQLForeignKeys, SQLPrimaryKeys (patches from Jon Smirl)
Thanks (again), Jon, for providing the build_results function to help reduce duplicate code!

Worked on LongTruncOk for Openlink drivers.

Note: those trying to bind variables need to remember that you should use the following syntax:

	use DBI;
	...
	$sth->bind_param(1, $str, DBI::SQL_LONGVARCHAR);

Added support for unixodbc (per Nick Gorham)
Added support for OpenLinks udbc (per Patrick van Kleef)
Added Support for esodbc (per Martin Evans)
Added Support for Easysoft (per Bob Kline)

Changed table_info to produce a list of views, too.
Fixed bug in SQLColumns call.
Fixed blob handling via patches from Jochen Wiedmann.
Added data_sources capability via snarfing code from DBD::Adabas (Jochen Wiedmann)

=head2 Changes in DBD::ODBC 0.20

SQLColAttributes fixes for SQL Server and MySQL. Fixed tables method
by renaming to new table_info method. Added new tyoe_info_all method.
Improved Makefile.PL support for Adabase.

=head2 Changes in DBD::ODBC 0.19

Added iODBC source code to distribution.Fall-back to using iODBC header
files in some cases.

=head2 Changes in DBD::ODBC 0.18

Enhancements to build process. Better handling of errors in
error handling code.

=head2 Changes in DBD::ODBC 0.17

This release is mostly due to the good work of Jeff Urlwin.
My eternal thanks to you Jeff.

Fixed "SQLNumResultCols err" on joins and 'order by' with some
drivers (see Microsoft Knowledge Base article #Q124899).
Thanks to Paul O'Fallon for that one.

Added more (probably incomplete) support for unix ODBC in Makefile.PL

Increased default SQL_COLUMN_DISPLAY_SIZE and SQL_COLUMN_LENGTH to 2000
for drivers that don't provide a way to query them dynamically. Was 100!

When fetch reaches the end-of-data it automatically frees the internal
ODBC statement handle and marks the DBI statement handle as inactive
(thus an explicit 'finish' is *not* required).

Also:

  LongTruncOk for Oracle ODBC (where fbh->datalen < 0)
  Added tracing into SQLBindParameter (help diagnose oracle odbc bug)
  Fixed/worked around bug/result from Latest Oracle ODBC driver where in
     SQLColAttribute cbInfoValue was changed to 0 to indicate fDesc had a value
  Added work around for compiling w/ActiveState PRK (PERL_OBJECT)
  Updated tests to include date insert and type
  Added more "backup" SQL_xxx types for tests                                  
  Updated bind test to test binding select
  NOTE: bind insert fails on Paradox driver (don't know why)

Added support for: (see notes below)

  SQLGetInfo       via $dbh->func(xxx, GetInfo)
  SQLGetTypeInfo   via $dbh->func(xxx, GetTypeInfo)
  SQLDescribeCol   via $sth->func(colno, DescribeCol)
  SQLColAttributes via $sth->func(xxx, colno, ColAttributes)
  SQLGetFunctions  via $dbh->func(xxx, GetFunctions)
  SQLColumns       via $dbh->func(catalog, schema, table, column, 'columns')

Fixed $DBI::err to reflect the real ODBC error code
which is a 5 char code, not necessarily numeric.

Fixed fetches when LongTruncOk == 1.

Updated tests to pass more often (hopefully 100% <G>)

Updated tests to test long reading, inserting and the LongTruncOk attribute.

Updated tests to be less driver specific.  

They now rely upon SQLGetTypeInfo I<heavily> in order to create the tables.
The test use this function to "ask" the driver for the name of the SQL type
to correctly create long, varchar, etc types.  For example, in Oracle the
SQL_VARCHAR type is VARCHAR2, while MS Access uses TEXT for the SQL Name.  
Again, in Oracle the SQL_LONGVARCHAR is LONG, while in Access it's MEMO.
The tests currently handle this correctly (at least with Access and Oracle,
MS SQL server will be tested also).

=cut
