DISCONNECT
DISCONNECT — terminate a database connection
Synopsis
DISCONNECT connection_name
DISCONNECT [ CURRENT ]
DISCONNECT DEFAULT
DISCONNECT ALL
Description
DISCONNECT closes a connection (or all connections) to the database. 
Parameters
- connection_name
- A database connection name established by the - CONNECTcommand.
- CURRENT
- Close the “current” connection, which is either the most recently opened connection, or the connection set by the - SET CONNECTIONcommand. This is also the default if no argument is given to the- DISCONNECTcommand.
- DEFAULT
- Close the default connection. 
- ALL
- Close all open connections. 
Examples
int
main(void)
{
    EXEC SQL CONNECT TO testdb AS DEFAULT USER testuser;
    EXEC SQL CONNECT TO testdb AS con1 USER testuser;
    EXEC SQL CONNECT TO testdb AS con2 USER testuser;
    EXEC SQL CONNECT TO testdb AS con3 USER testuser;
    EXEC SQL DISCONNECT CURRENT;  /* close con3          */
    EXEC SQL DISCONNECT DEFAULT;  /* close DEFAULT       */
    EXEC SQL DISCONNECT ALL;      /* close con2 and con1 */
    return 0;
}
Compatibility
DISCONNECT is specified in the SQL standard.