Command line interface and control files

Depending on your unload objectives, you might be able to simply issue the unload command from the operating system command line. For more complex unloads, you might be required to construct a control file first, and then pass it to the Optim™ High Performance Unload command line with the -f option.

Control files give you total flexibility and power over the data. On the other hand, using the command line allows you to do perform quick, non-repetitive tasks, such as issue simple requests or instructions. You can also use the command line to override the corresponding options in a control file, so that you can reuse the control file without modifying it. For example, if you have a control file that you use for one database and you want to use it for another database without any other changes, you can use the -d option on the command line to overwrite the database name.

Figure 1 illustrates both methods:

Figure 1. Running Optim High Performance Unload from a command line or by using a control file

As shown in the figure, issuing unload instructions in a command line will generate only one output file, whereas issuing unload instructions in a control file can generate more than one output file.