Oracle Database Connection Strings in PHP

It's easy to get confused as to how to specificy your Oracle database connection string, and there's a handy new feature in Oracle 10g that makes this a whole lot easier. So here's a little rundown of the three ways to connect to Oracle databases. You can use the:

• tnsnames.ora file
• Full connection string
• Easy connect string

These examples show how to specificy an Oracle connection string using the new OCI8 functions in PHP.

tnsnames.ora File

The tnsnames.ora file is a client side file that maps an alias used by client programs to a database service. It is used to connect to a non-default database. Here you have to have an entry in the tnsnames.ora file, and reference the alias to that entry in your connection code.

PHP code:

oci_connect($un, $pw, 'MYDB');

tnsnames.ora entry

MYDB = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP) (HOST = mymachine.mydomain)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = MYDB.AU.ORACLE.COM)) )

Full Connection String

The full connection string does not require the use of a tnsnames.ora file. You need to enter the full connection string when you connect to the database in your code.

PHP code:

oci_connect($un, $pw, '(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=mymachine.mydomain)(PORT=1521)) (CONNECT_DATA=(SERVER=DEDICATED) (SERVICE_NAME = MYDB)))');

Easy Connect String

This is one Oracle 10g feature that I use daily. As I constantly connect to so many different databases in my day, this has saved me so much time as I don't have to configure anything, just know the machine name and the database alias and I'm off.

The easy connect string does not require the use of a tnsnames.ora file, and is an abbreviated version of the full connection string. you must have the Oracle 10g client-side libraries to use the easy connect string.

PHP code:

oci_connect($un, $pw, '//mymachine.mydomain:port/MYDB');