Oracle PL/SQL for DBAs

Loops in PL/SQL

PL/SQL offers three types of loops to provide you with the flexibility you need to write the most straightforward code to handle any particular situation. Most situations that require a loop could be written with any of the three loop constructs. If you do not pick the construct that is best suited for that particular requirement, however, you could end up having to write many additional lines of code. The resulting module would also be harder to understand and maintain.

To give you a feeling for the way the different loops solve their problems in different ways, consider the following three procedures. In each case, the procedure makes a call to display_total_sales for a particular year, for each year number between the start and end argument values.

In the following examples, the FOR loop clearly requires the smallest amount of code. Yet I can use it in this case only because I know that I will run the body of the loop a specific number of times. In many other situations, the number of times a loop must execute varies, so the FOR loop cannot be used.