The Watch list provides a convenient method of displaying different types of valid variable values on a single window while debugging your module. Only variables which resolve to a scalar value are valid. Stored package variables are not valid.
Suppose you want to monitor certain local and package variables as you step through code during a debugging session. You could display local variable values in the Variables window and package variable values in the PL/SQL Packages window. But by adding the local variables and package variables you want to keep track of in the Watch list, you can monitor value changes in one window, the Watch window.
You can track local and global variables, package variables, as well as form item values and variables in records and objects using the Watch list. For example:
When execution is next suspended at a different location, the variable values in the list are updated as needed if they are available in the current execution context. If a variable is not defined in the currently executing subprogram, #### displays in the cell instead of a value.