Mojo::Pg::Database(3p)

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

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

  notification
  $db->on(notification => sub ($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.

  $db->delete(some_table => sub ($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.

  $db->delete_p('some_table')->then(sub ($results) {
    ...
  })->catch(sub ($err) {
    ...
  })->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.

  $db->insert(some_table => {foo => 'bar'} => sub ($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.

  $db->insert_p(some_table => {foo => 'bar'})->then(sub ($results) {
    ...
  })->catch(sub ($err) {
    ...
  })->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.

  $db->query('INSERT INTO foo VALUES (?, ?, ?)' => @values => sub ($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.

  $db->query_p('INSERT INTO foo VALUES (?, ?, ?)' => @values)->then(sub ($results) {
    ...
  })->catch(sub ($err) {
    ...
  })->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.

  $db->select(some_table => ['foo'] => {bar => 'yada'} => sub ($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.

  $db->select_p(some_table => ['foo'] => {bar => 'yada'})->then(sub ($results) {
    ...
  })->catch(sub ($err) {
    ...
  })->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.

  $db->update(some_table => {foo => 'baz'} => {foo => 'bar'} => sub ($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.

  $db->update_p(some_table => {foo => 'baz'} => {foo => 'bar'})->then(sub ($results) {
    ...
  })->catch(sub ($err) {
    ...
  })->wait;

SEE ALSO
Mojo::Pg, Mojolicious::Guides, <https://mojolicious.org>.