CONNECT

   CONNECT — establish a database connection

Synopsis

CONNECT TO connection_target [ AS connection_name ] [ USER connection_user ]
CONNECT TO DEFAULT
CONNECT connection_user
DATABASE connection_target

Description

   The CONNECT command establishes a connection between the client and the
   PostgreSQL server.

Parameters

   connection_target #
          connection_target specifies the target server of the connection
          on one of several forms.

        [ database_name ] [ @host ] [ :port ] #
                Connect over TCP/IP

        unix:postgresql://host [ :port ] / [ database_name ] [
                ?connection_option ] #
                Connect over Unix-domain sockets

        tcp:postgresql://host [ :port ] / [ database_name ] [
                ?connection_option ] #
                Connect over TCP/IP

        SQL string constant #
                containing a value in one of the above forms

        host variable #
                host variable of type char[] or VARCHAR[] containing a
                value in one of the above forms

   connection_name #
          An optional identifier for the connection, so that it can be
          referred to in other commands. This can be an SQL identifier or
          a host variable.

   connection_user #
          The user name for the database connection.

          This parameter can also specify user name and password, using
          one the forms user_name/password, user_name IDENTIFIED BY
          password, or user_name USING password.

          User name and password can be SQL identifiers, string constants,
          or host variables.

   DEFAULT #
          Use all default connection parameters, as defined by libpq.

Examples

   Here a several variants for specifying connection parameters:
EXEC SQL CONNECT TO "connectdb" AS main;
EXEC SQL CONNECT TO "connectdb" AS second;
EXEC SQL CONNECT TO "unix:postgresql://200.46.204.71/connectdb" AS main USER con
nectuser;
EXEC SQL CONNECT TO "unix:postgresql://localhost/connectdb" AS main USER connect
user;
EXEC SQL CONNECT TO 'connectdb' AS main;
EXEC SQL CONNECT TO 'unix:postgresql://localhost/connectdb' AS main USER :user;
EXEC SQL CONNECT TO :db AS :id;
EXEC SQL CONNECT TO :db USER connectuser USING :pw;
EXEC SQL CONNECT TO @localhost AS main USER connectdb;
EXEC SQL CONNECT TO REGRESSDB1 as main;
EXEC SQL CONNECT TO AS main USER connectdb;
EXEC SQL CONNECT TO connectdb AS :id;
EXEC SQL CONNECT TO connectdb AS main USER connectuser/connectdb;
EXEC SQL CONNECT TO connectdb AS main;
EXEC SQL CONNECT TO connectdb@localhost AS main;
EXEC SQL CONNECT TO tcp:postgresql://localhost/ USER connectdb;
EXEC SQL CONNECT TO tcp:postgresql://localhost/connectdb USER connectuser IDENTI
FIED BY connectpw;
EXEC SQL CONNECT TO tcp:postgresql://localhost:20/connectdb USER connectuser IDE
NTIFIED BY connectpw;
EXEC SQL CONNECT TO unix:postgresql://localhost/ AS main USER connectdb;
EXEC SQL CONNECT TO unix:postgresql://localhost/connectdb AS main USER connectus
er;
EXEC SQL CONNECT TO unix:postgresql://localhost/connectdb USER connectuser IDENT
IFIED BY "connectpw";
EXEC SQL CONNECT TO unix:postgresql://localhost/connectdb USER connectuser USING
 "connectpw";
EXEC SQL CONNECT TO unix:postgresql://localhost/connectdb?connect_timeout=14 USE
R connectuser;

   Here is an example program that illustrates the use of host variables
   to specify connection parameters:
int
main(void)
{
EXEC SQL BEGIN DECLARE SECTION;
    char *dbname     = "testdb";    /* database name */
    char *user       = "testuser";  /* connection user name */
    char *connection = "tcp:postgresql://localhost:5432/testdb";
                                    /* connection string */
    char ver[256];                  /* buffer to store the version string */
EXEC SQL END DECLARE SECTION;

    ECPGdebug(1, stderr);

    EXEC SQL CONNECT TO :dbname USER :user;
    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL CO
MMIT;
    EXEC SQL SELECT version() INTO :ver;
    EXEC SQL DISCONNECT;

    printf("version: %s\n", ver);

    EXEC SQL CONNECT TO :connection USER :user;
    EXEC SQL SELECT pg_catalog.set_config('search_path', '', false); EXEC SQL CO
MMIT;
    EXEC SQL SELECT version() INTO :ver;
    EXEC SQL DISCONNECT;

    printf("version: %s\n", ver);

    return 0;
}

Compatibility

   CONNECT is specified in the SQL standard, but the format of the
   connection parameters is implementation-specific.

See Also

   DISCONNECT, SET CONNECTION