Oracle and Pro*C - Part 1 - Page 2

Configuring Your Pro*C Environment

Configuration is actually a two-part process. The first step is to configure your Pro*C environment, and after that is complete, configure Visual C++ so that the generated .c file will successfully compile, link, and run.

Oracle did a poor job of stating all of the necessary steps to configure your environment. There are some fairly obscure references to what is needed, and what is provided (the project files in the demo area) more than likely needs adjusting.

The .c files can be generated in one of two ways: via the command line or by using a GUI tool Oracle provides. To keep things simple, I will use the command line interface (using the "proc" command) and the pcscfg.cfg configuration file found in precomp\admin. With a properly configured pcscfg.cfg file, all that will be needed to generate the .c file is a simple "proc iname=input_file_name.pc" at the command prompt.

Assuming you are using the Scott/Tiger schema, your ORACLE_HOME is in C:\ora9i, and you have Visual C++ in C:\Program Files, this is what you need in the configuration file:

define=(WIN32_LEAN_AND_MEAN)
include=(C:\Program Files\Microsoft 
   Visual Studio\VC98\Include)
include=(c:\ora9i\precomp\PUBLIC)
include=(C:\ora9i\precomp\lib\msvc)
SQLCHECK=SEMANTICS
USERID=SCOTT/TIGER

Let's use the sample9 project (it extracts data based on the department number you provide). Change directory to sample9 in the demo\proc area. To create the sample9.c file, at the command prompt, enter

proc iname=sample9.pc

You should have a sample9.c file now. Earlier, I alluded to the fact that the .c file was "kind of sort of" already present. In a text editor such as TextPad (yes, it is a shameless plug), open the sample9.pc and sample9.c files and note the huge difference between them.

Configuring the Visual C++ Environment

If you are familiar with Visual Studio and jumped ahead, you will have noticed that the sample9.c file compiles okay, but fails to link. Here are the steps to enable a successful compile-link-run process:

Double-click the sample9.c file to start Visual C++. You should end up with a window like this:

Go to Tools>Options and select the Directories tab. Add the path to your ORACLE_HOME\bin directory (C:\ora9i\bin in my case) under the Executable files menu option for "Show directories for." Change the menu option to Include files and enter ORACLE_HOME\precomp\public. Change the menu option to Library files and enter ORACLE_HOME\precomp\lib\msvc (there should be a file named oraSQL9.lib there).

Add the oraSQL9.lib file to the Object/library modules under the Link tab in Project>Settings.

You are now ready to link and run. What sample9.exe does is shown below.

Okay, the results aren't that impressive, but if there were millions of rows, how well Pro*C, via C, performs may make you sit up and pay attention to what the utility can offer with respect to shaving significant amounts of time off of a query.

In Closing

With a little bit of C and a little bit of Oracle, you now have at your disposal the means to work outside of Oracle and create an application whose interface with Oracle is transparent to a user. In the next part of this series, I will demonstrate how you can build your own version of SQL*Loader.

» See All Articles by Columnist Steve Callan