Connecting to Oracle involves installing the Oracle Net Services client (better known as the Oracle Client). Configuring this software requires a DBA or other knowledgeable user as it involves a fairly complex configuration. If you have ever heard anyone mention the TNSNAMES.ORA file, that is the file that defines your connections. The regular client install is several hundred megabytes and includes many programs you will probably never use.
Starting in 10g, though, Oracle has introduced the Instant Client. This install requires about 200 MB. There is also an Instant Client Lite if English is the only language you will need (on the client side). Instant Client doesn't require you to install a full client configuration. You just need to install the pieces that you need for connecting.
You can get more information on the Oracle Instant Client here. You'll have to register (it's free) if you haven't already.
In addition to Oracle Instant Client, Oracle has added a nifty feature called Easy Connect Naming. Rather than setting up all of your connections in the TNSNAMES.ORA file, you can access them directly (a lot like a JDBC connect string). For example, to connect using SQL*Plus to the database DB1 on machine BIGBOX as user JIM with the password BOB, you would use the syntax:
SQLPLUS JIM/BOB@BIGBOX/DB1This is great for one-time connections and to make connecting easier.
And since you mentioned PL/SQL, SQL*Plus comes with the Oracle Client and is a tool for testing queries, writing reports and creating programs with PL/SQL.
Hope that helps.
This was first published in November 2005