The PDO_PGSQL Data Source Name (DSN) is composed of the following elements, delimited by spaces:
The DSN prefix is pgsql:.
The hostname on which the database server resides.
The port on which the database server is running.
The name of the database.
The name of the user for the connection. If you specify the user name in the DSN, PDO ignores the value of the user name argument in the PDO constructor.
The password of the user for the connection. If you specify the password in the DSN, PDO ignores the value of the password argument in the PDO constructor.