Power to Build

Home » CodeProject » Quick Tip – Oracle 11g Instant Client

Quick Tip – Oracle 11g Instant Client

Oracle 11g has 2 versions of clients, Instant Client which has minimum required files for connecting to Oracle and the full blown (thick?) client which has many drivers and tools like SQL*Plus etc. The full blown version seems to be more for the developer and the instant client seems to be suitable for end users.

Recently, we upgraded to Oracle 11g database. When our desktop admin made changes to a user’s PC to connect to our 11g database, one of the applications (in VB) stopped working. Incidentally, he had only installed Oracle instant client for end users, as it uses less space.

The VB application in question actually used OleDB to connect to Oracle. Apparently, the instant client we installed for this user did not include OleDB related files. This is why the connection failed. To make it work, we did the following:

1. Installed Instant Client for Oracle 11g (32bit) (option 1 during installation)

2. After the install we copied the OraOLEDB.dll files into the %ORACLE_HOME%\bin directory and registered it. (using regsvr32).

3. Created the directory C:\Oracle11g\Network\Admin and move over the tnsname.ora. (By default tnsnames.ora is left in Oracle11g folder. If you don’t move the file, you need to add/change TNS_ADMIN environment variable to point to the right directory.)

Once we did this, the VB application was able to connect to Oracle 11g through OleDB.


1. This is the minimum required client installation for Oracle. We didn’t install the full blown client, as it comes with SQL*Plus etc which the end user doesn’t need.

2. All the data access drivers are bundled in an optional package called ODAC. We didn’t want to install all the drivers for the user. So, copied only OleDB driver from here.

3. Apparently, SQL*Plus can be added on to instant client as well. See here for more information about Oracle instant Client. Question about connection strings has a hint for connection problems similar to ours.






  1. Great blog! Do you have any suggestions for aspiring writers?
    I’m planning to start my own site soon but I’m a little lost on everything.
    Would you recommend starting with a free platform like WordPress
    or go for a paid option? There are so many choices out there that I’m completely overwhelmed ..
    Any recommendations? Bless you!

    • SamV says:

      Hi, Thanks for stopping by. It can be really overwhelming when you start blogging. I’ve been doing it for a few years, it’s still confusing. But with time, it will all fall in place.

      May I ask what type of site yours will be? If you are doing blogging kind of site (like this page), I suggest you start with WordPress.com (or blogspot if you prefer Google option) first. You can try various templates etc. Once you get the hang of it, WordPress allows you to host your blog elsewhere for a fee or your own ISP may provide WordPress option.


Comments, please?

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: