ID_NULL built in function is used to determine that an object type variable is null or not null in Oracle Forms and returns a BOOLEAN value that indicates whether the object ID is available or not means it is null or not null. Below is the Syntax of ID_Null function:
Where Objectid can be one of the following objects: Alert, Block, Canvas, Editor, FormModule, GroupColumn, Item, LOV, MenuItem, ParamList, RecordGroup, Relation, REPORT_OBJECT, TabPage, Timer, Viewport, VisualAttribute and Window.
Use ID_NULL when you want to check for the existence of an object created dynamically at runtime. For example, if a specific record group already exists, you will receive an error message if you try to create that record group. To perform this check, follow this general process: Use the appropriate FIND_ Built-in to obtain the object ID. Use ID_NULL to check whether an object with that ID already exists. If the object does not exist, proceed to create it.
See Examples for ID_NULL with the following link: