Provided by: libmojo-pg-perl_4.18-1_all 
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. Note that this attribute is weakened.
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->insert('frameworks', {name => 'Catalyst'});
$db->insert('frameworks', {name => 'Mojolicious'});
$tx->commit;
};
say $@ if $@;
delete
my $results = $db->delete($table, \%where, \%options);
Generate a "DELETE" statement with "abstract" in Mojo::Pg (usually an SQL::Abstract::Pg
object) and execute it with "query". You can also append a callback to perform operations
non-blocking.
$db->delete(some_table => sub {
my ($db, $err, $results) = @_;
...
});
Mojo::IOLoop->start unless Mojo::IOLoop->is_running;
Use all the same argument variations you would pass to the "delete" method of
SQL::Abstract.
# "delete from some_table"
$db->delete('some_table');
# "delete from some_table where foo = 'bar'"
$db->delete('some_table', {foo => 'bar'});
# "delete from some_table where foo like '%test%'"
$db->delete('some_table', {foo => {-like => '%test%'}});
# "delete from some_table where foo = 'bar' returning id"
$db->delete('some_table', {foo => 'bar'}, {returning => 'id'});
delete_p
my $promise = $db->delete_p($table, \%where, \%options);
Same as "delete", but performs all operations non-blocking and returns a Mojo::Promise
object instead of accepting a callback.
$db->delete_p('some_table')->then(sub {
my $results = shift;
...
})->catch(sub {
my $err = shift;
...
})->wait;
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;
insert
my $results = $db->insert($table, \@values || \%fieldvals, \%options);
Generate an "INSERT" statement with "abstract" in Mojo::Pg (usually an SQL::Abstract::Pg
object) and execute it with "query". You can also append a callback to perform operations
non-blocking.
$db->insert(some_table => {foo => 'bar'} => sub {
my ($db, $err, $results) = @_;
...
});
Mojo::IOLoop->start unless Mojo::IOLoop->is_running;
Use all the same argument variations you would pass to the "insert" method of
SQL::Abstract.
# "insert into some_table (foo, baz) values ('bar', 'yada')"
$db->insert('some_table', {foo => 'bar', baz => 'yada'});
# "insert into some_table (foo) values ({1,2,3})"
$db->insert('some_table', {foo => [1, 2, 3]});
# "insert into some_table (foo) values ('bar') returning id"
$db->insert('some_table', {foo => 'bar'}, {returning => 'id'});
# "insert into some_table (foo) values ('bar') returning id, foo"
$db->insert('some_table', {foo => 'bar'}, {returning => ['id', 'foo']});
As well as some PostgreSQL specific extensions added by SQL::Abstract::Pg.
# "insert into some_table (foo) values ('{"test":23}')"
$db->insert('some_table', {foo => {-json => {test => 23}}});
# "insert into some_table (foo) values ('bar') on conflict do nothing"
$db->insert('some_table', {foo => 'bar'}, {on_conflict => undef});
Including operations commonly referred to as "upsert".
# "insert into t (a) values ('b') on conflict (a) do update set a = 'c'"
$db->insert('t', {a => 'b'}, {on_conflict => [a => {a => 'c'}]});
# "insert into t (a, b) values ('c', 'd')
# on conflict (a, b) do update set a = 'e'"
$db->insert(
't', {a => 'c', b => 'd'}, {on_conflict => [['a', 'b'] => {a => 'e'}]});
insert_p
my $promise = $db->insert_p($table, \@values || \%fieldvals, \%options);
Same as "insert", but performs all operations non-blocking and returns a Mojo::Promise
object instead of accepting a callback.
$db->insert_p(some_table => {foo => 'bar'})->then(sub {
my $results = shift;
...
})->catch(sub {
my $err = shift;
...
})->wait;
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 <http://www.postgresql.org/docs/current/static/sql.html> statement
and return a results object based on "results_class" (which is usually Mojo::Pg::Results)
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" or "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});
query_p
my $promise = $db->query_p('select * from foo');
Same as "query", but performs all operations non-blocking and returns a Mojo::Promise
object instead of accepting a callback.
$db->query_p('insert into foo values (?, ?, ?)' => @values)->then(sub {
my $results = shift;
...
})->catch(sub {
my $err = shift;
...
})->wait;
select
my $results = $db->select($source, $fields, $where, \%options);
Generate a "SELECT" statement with "abstract" in Mojo::Pg (usually an SQL::Abstract::Pg
object) and execute it with "query". You can also append a callback to perform operations
non-blocking.
$db->select(some_table => ['foo'] => {bar => 'yada'} => sub {
my ($db, $err, $results) = @_;
...
});
Mojo::IOLoop->start unless Mojo::IOLoop->is_running;
Use all the same argument variations you would pass to the "select" method of
SQL::Abstract.
# "select * from some_table"
$db->select('some_table');
# "select id, foo from some_table"
$db->select('some_table', ['id', 'foo']);
# "select * from some_table where foo = 'bar'"
$db->select('some_table', undef, {foo => 'bar'});
# "select * from some_table where foo like '%test%'"
$db->select('some_table', undef, {foo => {-like => '%test%'}});
As well as some PostgreSQL specific extensions added by SQL::Abstract::Pg.
# "select * from foo join bar on (bar.foo_id = foo.id)"
$db->select(['foo', ['bar', foo_id => 'id']]);
# "select * from foo left join bar on (bar.foo_id = foo.id)"
$db->select(['foo', [-left => 'bar', foo_id => 'id']]);
# "select foo as bar from some_table"
$db->select('some_table', [[foo => 'bar']]);
# "select * from some_table where foo = '[1,2,3]'"
$db->select('some_table', '*', {foo => {'=' => {-json => [1, 2, 3]}}});
# "select extract(epoch from foo) as foo, bar from some_table"
$db->select('some_table', [\'extract(epoch from foo) as foo', 'bar']);
# "select 'test' as foo, bar from some_table"
$db->select('some_table', [\['? as foo', 'test'], 'bar']);
Including a new last argument to pass many new options.
# "select * from some_table where foo = 'bar' order by id desc"
$db->select('some_table', '*', {foo => 'bar'}, {order_by => {-desc => 'id'}});
# "select * from some_table limit 10 offset 20"
$db->select('some_table', '*', undef, {limit => 10, offset => 20});
# "select * from some_table where foo = 23 group by foo, bar"
$db->select('some_table', '*', {foo => 23}, {group_by => ['foo', 'bar']});
# "select * from t where a = 'b' group by c having d = 'e'"
$db->select('t', '*', {a => 'b'}, {group_by => ['c'], having => {d => 'e'}});
# "select * from some_table where id = 1 for update"
$db->select('some_table', '*', {id => 1}, {for => 'update'});
# "select * from some_table where id = 1 for update skip locked"
$db->select('some_table', '*', {id => 1}, {for => \'update skip locked'});
select_p
my $promise = $db->select_p($source, $fields, $where, \%options);
Same as "select", but performs all operations non-blocking and returns a Mojo::Promise
object instead of accepting a callback.
$db->select_p(some_table => ['foo'] => {bar => 'yada'})->then(sub {
my $results = shift;
...
})->catch(sub {
my $err = shift;
...
})->wait;
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.
update
my $results = $db->update($table, \%fieldvals, \%where, \%options);
Generate an "UPDATE" statement with "abstract" in Mojo::Pg (usually an SQL::Abstract::Pg
object) and execute it with "query". You can also append a callback to perform operations
non-blocking.
$db->update(some_table => {foo => 'baz'} => {foo => 'bar'} => sub {
my ($db, $err, $results) = @_;
...
});
Mojo::IOLoop->start unless Mojo::IOLoop->is_running;
Use all the same argument variations you would pass to the "update" method of
SQL::Abstract.
# "update some_table set foo = 'bar' where id = 23"
$db->update('some_table', {foo => 'bar'}, {id => 23});
# "update some_table set foo = {1,2,3} where id = 23"
$db->update('some_table', {foo => [1, 2, 3]}, {id => 23});
# "update some_table set foo = 'bar' where foo like '%test%'"
$db->update('some_table', {foo => 'bar'}, {foo => {-like => '%test%'}});
# "update some_table set foo = 'bar' where id = 23 returning id"
$db->update('some_table', {foo => 'bar'}, {id => 23}, {returning => 'id'});
# "update some_table set foo = '[1,2,3]' where bar = 23"
$db->update('some_table', {foo => {-json => [1, 2, 3]}}, {bar => 23});
update_p
my $promise = $db->update_p($table, \%fieldvals, \%where, \%options);
Same as "update", but performs all operations non-blocking and returns a Mojo::Promise
object instead of accepting a callback.
$db->update_p(some_table => {foo => 'baz'} => {foo => 'bar'})->then(sub {
my $results = shift;
...
})->catch(sub {
my $err = shift;
...
})->wait;
SEE ALSO
Mojo::Pg, Mojolicious::Guides, <https://mojolicious.org>.