NAME
Mojo::SQLite - A tiny Mojolicious wrapper for SQLite
SYNOPSIS
use Mojo::SQLite;
# Create a table
my $sql = Mojo::SQLite->new->from_filename($filename);
$sql->db->query('create table names (id integer primary key autoincrement, name text)');
# 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;
# Select one row at a time
my $results = $db->query('select * from names');
while (my $next = $results->hash) {
say $next->{name};
}
# Select all rows
$db->query('select * from names')
->hashes->map(sub { $_->{name} })->join("\n")->say;
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->from_filename(shift->config('sqlite_filename')) };
get '/' => sub {
my $c = shift;
my $db = $c->sqlite->db;
$c->render(json => $db->query('select datetime("now","localtime") as time')->hash);
};
app->start;
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 file (this is
the default).
EVENTS
Mojo::SQLite inherits all events from Mojo::EventEmitter and can emit
the following new ones.
connection
$sql->on(connection => sub {
my ($sql, $dbh) = @_;
...
});
Emitted when a new database connection has been established.
ATTRIBUTES
Mojo::SQLite implements the following attributes.
dsn
my $dsn = $sql->dsn;
$sql = $sql->dsn('dbi:SQLite:uri=file:foo.db');
Data source name, defaults to a dbi:SQLite:uri= followed by a URI 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.
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');
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 Mojo::SQLite::Database object 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 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');
Parse database filename directly. Unlike "from_string", the filename is
parsed as a local filename and not a URI, and "options" must be
specified separately.
# 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)->tap(sub { $_->options->{PrintError} = 1 });
from_string
$sql = $sql->from_string('file:test.db');
Parse configuration from connection string. Connection strings are
parsed as URIs, so you should construct them using a module like
Mojo::URL or URI::file. URI::file is recommended for portability on
non-Unix-like systems. The scheme and hostname are optional, but if
specified must be file and localhost respectively. If the connection
string has a query string, it will be parsed and applied to "options".
# Absolute filename
$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('file:data.db');
$sql->from_string('data.db');
# Connection string must be a valid URI
$sql->from_string(Mojo::URL->new->path($unix_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');
$sql->from_string(URI::file->new($filename)->Mojo::Base::tap(query_form_hash => {PrintError => 1}));
REFERENCE
This is the class hierarchy of the Mojo::SQLite distribution.
* Mojo::SQLite
* Mojo::SQLite::Database
* Mojo::SQLite::Migrations
* 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