/ 
Mojo-Pg-2.34
River stage two • 12 direct dependents • 14 total dependents
/ Mojo::Pg::Database

NAME

Mojo::Pg::Database - Database

SYNOPSIS

use Mojo::Pg::Database;

my $db = Mojo::Pg::Database->new(pg => $pg, dbh => $dbh);
$db->query('select * from foo')
  ->hashes->map(sub { $_->{bar} })->join("\n")->say;

DESCRIPTION

Mojo::Pg::Database is a container for DBD::Pg database handles used by Mojo::Pg.

EVENTS

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

close

$db->on(close => sub {
  my $db = shift;
  ...
});

Emitted when the database connection gets closed while waiting for notifications.

notification

$db->on(notification => sub {
  my ($db, $name, $pid, $payload) = @_;
  ...
});

Emitted when a notification has been received.

ATTRIBUTES

Mojo::Pg::Database implements the following attributes.

dbh

my $dbh = $db->dbh;
$db     = $db->dbh($dbh);

DBD::Pg database handle used for all queries.

# Use DBI utility methods
my $quoted = $db->dbh->quote_identifier('foo.bar');

pg

my $pg = $db->pg;
$db    = $db->pg(Mojo::Pg->new);

Mojo::Pg object this database belongs to.

results_class

my $class = $db->results_class;
$db       = $db->results_class('MyApp::Results');

Class to be used by "query", defaults to Mojo::Pg::Results. Note that this class needs to have already been loaded before "query" is called.

METHODS

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

begin

my $tx = $db->begin;

Begin transaction and return Mojo::Pg::Transaction object, which will automatically roll back the transaction unless "commit" in Mojo::Pg::Transaction has been called before it is destroyed.

# Insert rows in a transaction
eval {
  my $tx = $db->begin;
  $db->query('insert into frameworks values (?)', 'Catalyst');
  $db->query('insert into frameworks values (?)', 'Mojolicious');
  $tx->commit;
};
say $@ if $@;

disconnect

$db->disconnect;

Disconnect "dbh" and prevent it from getting reused.

dollar_only

$db = $db->dollar_only;

Activate pg_placeholder_dollaronly for next "query" call and allow ? to be used as an operator.

# Check for a key in a JSON document
$db->dollar_only->query('select * from foo where bar ? $1', 'baz')
  ->expand->hashes->map(sub { $_->{bar}{baz} })->join("\n")->say;

is_listening

my $bool = $db->is_listening;

Check if "dbh" is listening for notifications.

listen

$db = $db->listen('foo');

Subscribe to a channel and receive "notification" events when the Mojo::IOLoop event loop is running.

notify

$db = $db->notify('foo');
$db = $db->notify(foo => 'bar');

Notify a channel.

pid

my $pid = $db->pid;

Return the process id of the backend server process.

ping

my $bool = $db->ping;

Check database connection.

query

my $results = $db->query('select * from foo');
my $results = $db->query('insert into foo values (?, ?, ?)', @values);
my $results = $db->query('select ?::json as foo', {json => {bar => 'baz'}});

Execute a blocking SQL statement and return a results object based on "results_class" with the query results. The DBD::Pg statement handle will be automatically reused when it is not active anymore, to increase the performance of future queries. You can also append a callback to perform operations non-blocking.

$db->query('insert into foo values (?, ?, ?)' => @values => sub {
  my ($db, $err, $results) = @_;
  ...
});
Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

Hash reference arguments containing a value named json, will be encoded to JSON text with "to_json" in Mojo::JSON. To accomplish the reverse, you can use the method "expand" in Mojo::Pg::Results, which automatically decodes all fields of the types json and jsonb with "from_json" in Mojo::JSON to Perl values.

# "I ♥ Mojolicious!"
$db->query('select ?::jsonb as foo', {json => {bar => 'I ♥ Mojolicious!'}})
  ->expand->hash->{foo}{bar};

Hash reference arguments containing values named type and value, can be used to bind specific DBD::Pg data types to placeholders.

# Insert binary data
use DBD::Pg ':pg_types';
$db->query('insert into bar values (?)', {type => PG_BYTEA, value => $bytes});

tables

my $tables = $db->tables;

Return table and view names for this database, that are visible to the current user and not internal, as an array reference.

# Names of all tables
say for @{$db->tables};

unlisten

$db = $db->unlisten('foo');
$db = $db->unlisten('*');

Unsubscribe from a channel, * can be used to unsubscribe from all channels.

SEE ALSO

Mojo::Pg, Mojolicious::Guides, http://mojolicious.org.