PostgreSQL Functions
PHP Manual


(PHP 4, PHP 5, PHP 7)

pg_connectOpen a PostgreSQL connection


resource pg_connect ( string $connection_string [, int $connect_type ] )

pg_connect() opens a connection to a PostgreSQL database specified by the connection_string.

If a second call is made to pg_connect() with the same connection_string as an existing connection, the existing connection will be returned unless you pass PGSQL_CONNECT_FORCE_NEW as connect_type.

The old syntax with multiple parameters $conn = pg_connect("host", "port", "options", "tty", "dbname") has been deprecated.



The connection_string can be empty to use all default parameters, or it can contain one or more parameter settings separated by whitespace. Each parameter setting is in the form keyword = value. Spaces around the equal sign are optional. To write an empty value or a value containing spaces, surround it with single quotes, e.g., keyword = 'a value'. Single quotes and backslashes within the value must be escaped with a backslash, i.e., \' and \\.

The currently recognized parameter keywords are: host, hostaddr, port, dbname (defaults to value of user), user, password, connect_timeout, options, tty (ignored), sslmode, requiressl (deprecated in favor of sslmode), and service. Which of these arguments exist depends on your PostgreSQL version.

The options parameter can be used to set command line parameters to be invoked by the server.


If PGSQL_CONNECT_FORCE_NEW is passed, then a new connection is created, even if the connection_string is identical to an existing connection.

If PGSQL_CONNECT_ASYNC is given, then the connection is established asynchronously. The state of the connection can then be checked via pg_connect_poll() or pg_connection_status().

Return Values

PostgreSQL connection resource on success, FALSE on failure.


Version Description
5.6.0 Support for giving the PGSQL_CONNECT_ASYNC constant as the connect_type was added.


Example #1 Using pg_connect()

//connect to a database named "mary"

$dbconn2 pg_connect("host=localhost port=5432 dbname=mary");
// connect to a database named "mary" on "localhost" at port "5432"

$dbconn3 pg_connect("host=sheep port=5432 dbname=mary user=lamb password=foo");
//connect to a database named "mary" on the host "sheep" with a username and password

$conn_string "host=sheep port=5432 dbname=test user=lamb password=bar";
$dbconn4 pg_connect($conn_string);
//connect to a database named "test" on the host "sheep" with a username and password

$dbconn5 pg_connect("host=localhost options='--client_encoding=UTF8'");
//connect to a database on "localhost" and set the command line parameter which tells the encoding is in UTF-8

See Also

PostgreSQL Functions
PHP Manual