NAME

    Mojo::SQLite - A tiny Mojolicious wrapper for SQLite

SYNOPSIS

      use Mojo::SQLite;
    
      # Select the library version
      my $sql = Mojo::SQLite->new('sqlite:test.db');
      say $sql->db->query('select sqlite_version() as version')->hash->{version};
    
      # Use migrations to create a table
      $sql->migrations->name('my_names_app')->from_string(<<EOF)->migrate;
      -- 1 up
      create table names (id integer primary key autoincrement, name text);
      -- 1 down
      drop table names;
      EOF
    
      # Use migrations to drop and recreate the table
      $sql->migrations->migrate(0)->migrate;
    
      # Insert a few rows
      my $db = $sql->db;
      $db->query('insert into names (name) values (?)', 'Sara');
      $db->query('insert into names (name) values (?)', 'Stefan');
    
      # Insert more rows in a transaction
      eval {
        my $tx = $db->begin;
        $db->query('insert into names (name) values (?)', 'Baerbel');
        $db->query('insert into names (name) values (?)', 'Wolfgang');
        $tx->commit;
      };
      say $@ if $@;
    
      # Insert another row and return the generated id
      say $db->query('insert into names (name) values (?)', 'Daniel')
        ->last_insert_id;
      
      # JSON roundtrip
      say $db->query('select ? as foo', {json => {bar => 'baz'}})
        ->expand(json => 'foo')->hash->{foo}{bar};
    
      # Select one row at a time
      my $results = $db->query('select * from names');
      while (my $next = $results->hash) {
        say $next->{name};
      }
    
      # Select all rows
      say $_->{name} for $db->query('select * from names')->hashes->each;
    
      # Send and receive notifications non-blocking
      $sql->pubsub->listen(foo => sub {
        my ($pubsub, $payload) = @_;
        say "foo: $payload";
        $pubsub->notify(bar => $payload);
      });
      $sql->pubsub->listen(bar => sub {
        my ($pubsub, $payload) = @_;
        say "bar: $payload";
      });
      $sql->pubsub->notify(foo => 'SQLite rocks!');
      Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

DESCRIPTION

    Mojo::SQLite is a tiny wrapper around DBD::SQLite that makes SQLite
    <https://www.sqlite.org/> a lot of fun to use with the Mojolicious
    <https://mojolico.us> real-time web framework.

    Database and statement handles are cached automatically, so they can be
    reused transparently to increase performance. And you can handle
    connection timeouts gracefully by holding on to them only for short
    amounts of time.

      use Mojolicious::Lite;
      use Mojo::SQLite;
    
      helper sqlite => sub { state $sql = Mojo::SQLite->new('sqlite:test.db') };
    
      get '/' => sub {
        my $c  = shift;
        my $db = $c->sqlite->db;
        $c->render(json => $db->query('select datetime("now","localtime") as now')->hash);
      };
    
      app->start;

    In this example application, we create a sqlite helper to store a
    Mojo::SQLite object. Our action calls that helper and uses the method
    "db" in Mojo::SQLite to dequeue a Mojo::SQLite::Database object from
    the connection pool. Then we use the method "query" in
    Mojo::SQLite::Database to execute an SQL
    <http://www.postgresql.org/docs/current/static/sql.html> statement,
    which returns a Mojo::SQLite::Results object. And finally we call the
    method "hash" in Mojo::SQLite::Results to retrieve the first row as a
    hash reference.

    All I/O and queries are performed synchronously. However, the
    "Write-Ahead Log" journal is enabled for all connections, allowing
    multiple processes to read and write concurrently to the same database
    file (but only one can write at a time). See http://sqlite.org/wal.html
    for more information.

      # Performed concurrently
      my $pid = fork || die $!;
      say $sql->db->query('select datetime("now","localtime") as time')->hash->{time};
      exit unless $pid;

    All cached database handles will be reset automatically if a new
    process has been forked, this allows multiple processes to share the
    same Mojo::SQLite object safely.

    Any database errors will throw an exception as RaiseError is
    automatically enabled, so use eval or Try::Tiny to catch them. This
    makes transactions with "begin" in Mojo::SQLite::Database easy.

    While passing a file path of :memory: (or a custom "dsn" with
    mode=memory) will create a temporary database, in-memory databases
    cannot be shared between connections, so subsequent calls to "db" may
    return connections to completely different databases. For a temporary
    database that can be shared between connections and processes, pass a
    file path of :temp: to store the database in a temporary directory
    (this is the default), or consider constructing a temporary directory
    yourself with File::Temp if you need to reuse the filename. A temporary
    directory allows SQLite to create additional temporary files
    <https://www.sqlite.org/tempfiles.html> safely.

      use File::Spec::Functions 'catfile';
      use File::Temp;
      use Mojo::SQLite;
      my $tempdir = File::Temp->newdir; # Deleted when object goes out of scope
      my $tempfile = catfile $tempdir, 'test.db';
      my $sql = Mojo::SQLite->new->from_filename($tempfile);

EVENTS

    Mojo::SQLite inherits all events from Mojo::EventEmitter and can emit
    the following new ones.

 connection

      $sql->on(connection => sub {
        my ($sql, $dbh) = @_;
        $dbh->do('pragma journal_size_limit=1000000');
      });

    Emitted when a new database connection has been established.

ATTRIBUTES

    Mojo::SQLite implements the following attributes.

 auto_migrate

      my $bool = $sql->auto_migrate;
      $sql     = $sql->auto_migrate($bool);

    Automatically migrate to the latest database schema with "migrations",
    as soon as the first database connection has been established.

 database_class

      my $class = $sql->database_class;
      $sql      = $sql->database_class('MyApp::Database');

    Class to be used by "db", defaults to Mojo::SQLite::Database. Note that
    this class needs to have already been loaded before "db" is called.

 dsn

      my $dsn = $sql->dsn;
      $sql    = $sql->dsn('dbi:SQLite:uri=file:foo.db');

    Data source name, defaults to dbi:SQLite:dbname= followed by a path to
    a temporary file.

 max_connections

      my $max = $sql->max_connections;
      $sql    = $sql->max_connections(3);

    Maximum number of idle database handles to cache for future use,
    defaults to 5.

 migrations

      my $migrations = $sql->migrations;
      $sql           = $sql->migrations(Mojo::SQLite::Migrations->new);

    Mojo::SQLite::Migrations object you can use to change your database
    schema more easily.

      # Load migrations from file and migrate to latest version
      $sql->migrations->from_file('/home/dbook/migrations.sql')->migrate;

 options

      my $options = $sql->options;
      $sql        = $sql->options({AutoCommit => 1, RaiseError => 1});

    Options for database handles, defaults to activating sqlite_unicode,
    AutoCommit, AutoInactiveDestroy as well as RaiseError and deactivating
    PrintError. Note that AutoCommit and RaiseError are considered
    mandatory, so deactivating them would be very dangerous. See
    "ATTRIBUTES COMMON TO ALL HANDLES" in DBI and "DRIVER PRIVATE
    ATTRIBUTES" in DBD::SQLite for more information on available options.

 pubsub

      my $pubsub = $sql->pubsub;
      $sql       = $sql->pubsub(Mojo::SQLite::PubSub->new);

    Mojo::SQLite::PubSub object you can use to send and receive
    notifications very efficiently, by sharing a single database connection
    with many consumers.

      # Subscribe to a channel
      $sql->pubsub->listen(news => sub {
        my ($pubsub, $payload) = @_;
        say "Received: $payload";
      });
    
      # Notify a channel
      $sql->pubsub->notify(news => 'SQLite rocks!');

METHODS

    Mojo::SQLite inherits all methods from Mojo::EventEmitter and
    implements the following new ones.

 new

      my $sql = Mojo::SQLite->new;
      my $sql = Mojo::SQLite->new('file:test.db);
      my $sql = Mojo::SQLite->new('sqlite:test.db');

    Construct a new Mojo::SQLite object and parse connection string with
    "from_string" if necessary.

      # Customize configuration further
      my $sql = Mojo::SQLite->new->dsn('dbi:SQLite:dbname=test.db');
      my $sql = Mojo::SQLite->new->dsn('dbi:SQLite:uri=file:test.db?mode=memory');
    
      # Pass filename directly
      my $sql = Mojo::SQLite->new->from_filename($filename);

 db

      my $db = $sql->db;

    Get a database object based on "database_class" for a cached or newly
    established database connection. The DBD::SQLite database handle will
    be automatically cached again when that object is destroyed, so you can
    handle problems like connection timeouts gracefully by holding on to it
    only for short amounts of time.

      # Add up all the money
      say $sql->db->query('select * from accounts')
        ->hashes->reduce(sub { $a->{money} + $b->{money} });

 from_filename

      $sql = $sql->from_filename('C:\\Documents and Settings\\foo & bar.db', $options);

    Parse database filename directly. Unlike "from_string", the filename is
    parsed as a local filename and not a URL. A hashref of "options" may be
    passed as the second argument.

      # Absolute filename
      $sql->from_filename('/home/fred/data.db');
    
      # Relative to current directory
      $sql->from_filename('data.db');
    
      # Temporary file database (default)
      $sql->from_filename(':temp:');
    
      # In-memory temporary database (single connection only)
      my $db = $sql->from_filename(':memory:')->db;
    
      # Additional options
      $sql->from_filename($filename, { PrintError => 1 });

 from_string

      $sql = $sql->from_string('test.db');
      $sql = $sql->from_string('file:test.db');
      $sql = $sql->from_string('file:///C:/foo/bar.db');
      $sql = $sql->from_string('sqlite:C:%5Cfoo%5Cbar.db');

    Parse configuration from connection string. Connection strings are
    parsed as URLs, so you should construct them using a module like
    Mojo::URL, URI::file, or URI::db. For portability on non-Unix-like
    systems, either construct the URL with the sqlite scheme, or use "new"
    in URI::file to construct a URL with the file scheme. A URL with no
    scheme will be parsed as a file URL, and file URLs are parsed according
    to the current operating system. If specified, the hostname must be
    localhost. If the URL has a query string, it will be parsed and applied
    to "options".

      # Absolute filename
      $sql->from_string('sqlite:////home/fred/data.db');
      $sql->from_string('sqlite://localhost//home/fred/data.db');
      $sql->from_string('sqlite:/home/fred/data.db');
      $sql->from_string('file:///home/fred/data.db');
      $sql->from_string('file://localhost/home/fred/data.db');
      $sql->from_string('file:/home/fred/data.db');
      $sql->from_string('///home/fred/data.db');
      $sql->from_string('//localhost/home/fred/data.db');
      $sql->from_string('/home/fred/data.db');
    
      # Relative to current directory
      $sql->from_string('sqlite:data.db');
      $sql->from_string('file:data.db');
      $sql->from_string('data.db');
    
      # Connection string must be a valid URL
      $sql->from_string(Mojo::URL->new->scheme('sqlite')->path($filename));
      $sql->from_string(URI::db->new->Mojo::Base::tap(engine => 'sqlite')->Mojo::Base::tap(dbname => $filename));
      $sql->from_string(URI::file->new($filename));
    
      # Temporary file database (default)
      $sql->from_string(':temp:');
    
      # In-memory temporary database (single connection only)
      my $db = $sql->from_string(':memory:')->db;
    
      # Additional options
      $sql->from_string('data.db?PrintError=1&sqlite_allow_multiple_statements=1');
      $sql->from_string(Mojo::URL->new->scheme('sqlite')->path($filename)->query(sqlite_see_if_its_a_number => 1));
      $sql->from_string(URI::file->new($filename)->Mojo::Base::tap(query_form => {PrintError => 1}));

REFERENCE

    This is the class hierarchy of the Mojo::SQLite distribution.

      * Mojo::SQLite

      * Mojo::SQLite::Database

      * Mojo::SQLite::Migrations

      * Mojo::SQLite::PubSub

      * Mojo::SQLite::Results

      * Mojo::SQLite::Transaction

BUGS

    Report any issues on the public bugtracker.

AUTHOR

    Dan Book, dbook@cpan.org

CREDITS

    Sebastian Riedel, author of Mojo::Pg, which this distribution is based
    on.

COPYRIGHT AND LICENSE

    Copyright 2015, Dan Book.

    This library is free software; you may redistribute it and/or modify it
    under the terms of the Artistic License version 2.0.

SEE ALSO

    Mojolicious, Mojo::Pg, DBD::SQLite

