=pod

=head1 NAME

Mojo::SQLite - A tiny Mojolicious wrapper for SQLite

=head1 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;

Get a database handle from the cache for multiple queries

my $db = $sql->db;

Use SQL::Abstract to generate simple CRUD queries for you

$db->insert('names', {name => 'Isabel'}); my $id = $db->select('names', ['id'], {name => 'Isabel'})->hash->{id}; $db->update('names', {name => 'Bel'}, {id => $id}); $db->delete('names', {name => 'Bel'});

Insert a few rows in a transaction with SQL and placeholders

eval { my $tx = $db->begin; $db->query('insert into names (name) values (?)', 'Sara'); $db->query('insert into names (name) values (?)', 'Stefan'); $tx->commit; }; say $@ if $@;

Insert another row with SQL::Abstract and return the generated id

say $db->insert('names', {name => '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 with SQL::Abstract

say $_->{name} for $db->select('names')->hashes->each;

=head1 DESCRIPTION

L is a tiny wrapper around L that makes L<SQLite|https://www.sqlite.org/> a lot of fun to use with the L<Mojolicious|https://mojolico.us> real-time web framework. Use all L<SQL features|http://sqlite.org/lang.html> SQLite has to offer, generate CRUD queries from data structures, and manage your database schema with migrations.

=head1 BASICS

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 ($c) { my $db = $c->sqlite->db; $c->render(json => $db->query(q{select datetime('now','localtime') as now})->hash); };

app->start;

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

All I/O and queries are performed synchronously, and SQLite's default journal mode only supports concurrent reads from multiple processes while the database is not being written. The "Write-Ahead Log" journal mode allows multiple processes to read and write concurrently to the same database file (but only one can write at a time). WAL mode is enabled by the C option, currently enabled by default, and persists when opening that same database in the future.

Performed concurrently (concurrent with writing only with WAL journaling mode)

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

The C option prevents WAL mode from being enabled in new databases but doesn't affect databases where it has already been enabled. C may not be set by default in a future release. See Lhttp://sqlite.org/wal.html and L<DBD::SQLite/"journal_mode"> for more information.

The L<double-quoted string literal misfeature |https://sqlite.org/quirks.html#double_quoted_string_literals_are_accepted> is disabled for all connections since Mojo::SQLite 3.003; use single quotes for string literals and double quotes for identifiers, as is normally recommended.

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

Any database errors will throw an exception as C is automatically enabled, so use C or L to catch them. This makes transactions with L<Mojo::SQLite::Database/"begin"> easy.

While passing a file path of C<:memory:> (or a custom L</"dsn"> with C) will create a temporary database, in-memory databases cannot be shared between connections, so subsequent calls to L</"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 C<:temp:> to store the database in a temporary directory (this is the default), or consider constructing a temporary directory yourself with L if you need to reuse the filename. A temporary directory allows SQLite to create L<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);

=head1 EXAMPLES

This distribution also contains a well-structured example L<blog application|https://github.com/Grinnz/Mojo-SQLite/tree/master/examples/blog> you can use for inspiration. This application shows how to apply the MVC design pattern in practice.

=head1 EVENTS

L inherits all events from L and can emit the following new ones.

=head2 connection

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

Emitted when a new database connection has been established.

=head1 ATTRIBUTES

L implements the following attributes.

=head2 abstract

my $abstract = $sql->abstract; $sql = $sql->abstract(SQL::Abstract->new);

L object used to generate CRUD queries for L, defaults to a L object with C set to C<.> and C set to C<">.

Generate WHERE clause and bind values

my($stmt, @bind) = $sql->abstract->where({foo => 'bar', baz => 'yada'});

L provides additional features to the L query methods in L such as C<-json> and C/C. The C feature is not applicable to SQLite queries.

$sql->db->select(['some_table', ['other_table', foo_id => 'id']], ['foo', [bar => 'baz'], \q{datetime('now') as dt}], {foo => 'value'}, {order_by => 'foo', limit => 10, offset => 5, group_by => ['foo'], having => {baz => 'value'}});

Upsert supported since SQLite 3.24.0

$sql->db->insert('some_table', {name => $name, value => $value}, {on_conflict => [name => {value => \'"excluded"."value"'}]});

=head2 auto_migrate

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

Automatically migrate to the latest database schema with L</"migrations">, as soon as L</"db"> has been called for the first time.

=head2 database_class

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

Class to be used by L</"db">, defaults to L. Note that this class needs to have already been loaded before L</"db"> is called.

=head2 dsn

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

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

=head2 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 C<1>.

=head2 migrations

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

L 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;

=head2 options

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

Options for database handles, defaults to setting C to C, setting C, C and C, and deactivating C. Note that C and C are considered mandatory, so deactivating them would be very dangerous. See L<DBI/"ATTRIBUTES COMMON TO ALL HANDLES"> and L<DBD::SQLite/"DRIVER PRIVATE ATTRIBUTES"> for more information on available options.

=head2 parent

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

Another L object to use for connection management, instead of establishing and caching our own database connections.

=head1 METHODS

L inherits all methods from L and implements the following new ones.

=head2 new

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

Construct a new L object and parse connection string with L</"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);

=head2 db

my $db = $sql->db;

Get a database object based on L</"database_class"> (which is usually L) for a cached or newly established database connection. The L 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->select('accounts') ->hashes->reduce(sub { $a->{money} + $b->{money} });

=head2 from_filename

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

Parse database filename directly. Unlike L</"from_string">, the filename is parsed as a local filename and not a URL. A hashref of L</"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 });

Readonly connection without WAL mode

$sql->from_filename($filename, { ReadOnly => 1, no_wal => 1 });

Strict unicode strings and WAL mode

use DBD::SQLite::Constants ':dbd_sqlite_string_mode'; $sql->from_filename($filename, { sqlite_string_mode => DBD_SQLITE_STRING_MODE_UNICODE_STRICT, wal_mode => 1 });

=head2 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'); $sql = $sql->from_string(Mojo::SQLite->new);

Parse configuration from connection string or use another L object as L</"parent">. Connection strings are parsed as URLs, so you should construct them using a module like L, L, or L. For portability on non-Unix-like systems, either construct the URL with the C scheme, or use L<URI::file/"new"> to construct a URL with the C scheme. A URL with no scheme will be parsed as a C URL, and C URLs are parsed according to the current operating system. If specified, the hostname must be C. If the URL has a query string, it will be parsed and applied to L</"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}));

Readonly connection without WAL mode

$sql->from_string('data.db?ReadOnly=1&no_wal=1');

String unicode strings and WAL mode

use DBD::SQLite::Constants ':dbd_sqlite_string_mode'; $sql->from_string(Mojo::URL->new->scheme('sqlite')->path('data.db') ->query(sqlite_string_mode => DBD_SQLITE_STRING_MODE_UNICODE_STRICT, wal_mode => 1));

=head1 DEBUGGING

You can set the C environment variable to get some advanced diagnostics information printed by L.

DBI_TRACE=1 DBI_TRACE=15 DBI_TRACE=SQL

=head1 REFERENCE

This is the class hierarchy of the L distribution.

=over 2

=item * L

=item * L

=item * L

=item * L

=item * L

=back

=head1 BUGS

Report any issues on the public bugtracker.

=head1 AUTHOR

Dan Book, Cdbook@cpan.org

=head1 CREDITS

Sebastian Riedel, author of L, which this distribution is based on.

=head1 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.

=head1 SEE ALSO

L, L, L

=cut