Controlling Execution

Topics in this section include:

Starting Debugging
Single Stepping a PL/SQL Function
Continuing the Debugging
Viewing Callstack

Starting Debugging

Select the function that you want to debug in the Object Browser pane. Start debugging by clicking on the toolbar or using any other method mentioned in previous sections. If no breakpoint is set or the breakpoint set is invalid, the debugging operation is performed without stopping any statement and Data Studio will simply execute the object and display the results (if any).

Single Stepping a PL/SQL Function

You can run the command for single stepping in the toolbar to debug a function. This allows you to debug the program line by line. When a breakpoint occurs during the operation of single stepping, the operation will be suspended and the program will be stopped.

Single stepping means executing one statement at a time. Once a statement is executed, you can see the execution result in other debugging tabs.

A maximum of 100 PL/SQL Viewer tabs can be displayed at a time. If more than 100 tabs are opened, the tabs of function calls will be closed. For example, if 100 tabs are opened and a new debugging object is called, Data Studio will close the tabs of function calls and open the tab of the new debugging object.

Step Into

To execute the code by statement, select Step Into from the Debug menu, or click , or press F7.

When stepping into a function, Data Studio executes the current statement and then enters the debugging mode. The debugged line will be indicated by an arrow on the left. If the executed statement calls another function, Data Studio will step into that function. Once you have stepped through all the statements in that function, Data Studio jumps to the next statement of the function it was called from.

Press F7 to go to the next statement. If you click Continue, PL/SQL code execution will continue.

An example is as follows:

When entering line 8, enter m := F3_TEST();. That is, go to line 9 in f3_test(). You can step through all the statements in f3_test() by pressing F7 repeatedly to step into each line. Once you have stepped through all the statements in that function, Data Studio jumps to line 10 in f2_test().

The currently debugged object is marked with the symbol in the tab title, which indicates the function name.

Stepping Over

Stepping over is the same as Stepping into, except that when it reaches a call for another function, it will not step into the function. The function will run, and you will be brought to the next statement in the current function. F8 is the shortcut key for Step Over. However, if there is a breakpoint set inside the called function, Step Over will enter the function, and hit the set breakpoint.

In the following example, when you click Step Over in line 10, Data Studio executes the f3_test() function.

The cursor will be moved to the next statement in f2_test(), that is, line 11 in f2_test().

You can step over a function when you are familiar with the way the function works and ensure that its execution will not affect the debugging.

Stepping over a line of code that does not contain a function call executes the line just like stepping into the line.

Stepping Out

Stepping out of a sub-program continues execution of the function and then suspends execution after the function returns to its calling function. You can step out of a long function when you have determined that the rest of the function is not significant to debug. However, if a breakpoint is set in the remaining part of the function, then that breakpoint will be hit before returning to the calling function.

A function will be executed when you step over or step out of it. Shift+F7 is the shortcut key for Step Out.

In the preceding example:

Choose Debug > Step Into to step into f3_test().
Choose Debug > Step Out to step out of f3_test().

Continuing the Debugging

When the debugged process stops at a specific location, you can select Continue (F9) from the Debug menu, or click in the toolbar to continue the PL/SQL function execution.

Viewing Callstack

The Callstack pane displays the chain of functions as they are called. The Callstack pane can be opened from the minimized window. The most recent functions are listed at the top, and the least recent at the bottom. At the end of each function name is the current line number in that function.

You can double-click the function names in the Callstack pane to open panes of different functions. For example, when f2_test() calls line 10 of f3_test(), the debugging pointer will point to the first executable line (that is, line 9 in the preceding example) in the function call.

In this case, the Callstack pane will be displayed as follows.