Postgres, developed originally in the UC Berkeley Computer Science Department, pioneered many of the object-relational concepts now becoming available in some commercial databases. It provides SQL92/SQL3 language support, transaction integrity, and type extensibility. PostgreSQL is a public-domain, open source descendant of this original Berkeley code.
PostgreSQL is available without cost. The current version is available at www.PostgreSQL.org.
Since version 6.3 (03/02/1998) PostgreSQL uses unix domain sockets. A table is shown below describing these new connection possibilities. This socket will be found in /tmp/.s.PGSQL.5432. This option can be enabled with the '-i' flag to postmaster and it's meaning is: "listen on TCP/IP sockets as well as Unix domain sockets".
Table 1. Postmaster and PHP
|postmaster &||pg_connect("", "", "", "", "dbname");||OK|
|postmaster -i &||pg_connect("", "", "", "", "dbname");||OK|
|postmaster &||pg_connect("localhost", "", "", "", "dbname");||Unable to connect to PostgreSQL server: connectDB() failed: Is the postmaster running and accepting TCP/IP (with -i) connection at 'localhost' on port '5432'? in /path/to/file.php3 on line 20.|
|postmaster -i &||pg_connect("localhost", "", "", "", "dbname");||OK|
One can also establish a connection with the following command: $conn = pg_Connect("host=localhost port=5432 dbname=chris");
To use the large object (lo) interface, it is necessary to enclose it within a transaction block. A transaction block starts with a begin and if the transaction was valid ends with commit and end. If the transaction fails the transaction should be closed with abort and rollback.
Example 1. Using Large Objects