Using Mapping Services › NCL Reference, Type Checking, and Data Behavior › NULL Type

NULL Type

The NULL type is used where data in a component either must be null (that is, empty), or not accessible.

• External Form - Input

  The only valid input is a null value.

• External Form - Output

  A null value is always returned.

• Local Form and Behavior

  The component can be created by an input operation, but no contents are modified. If it already exists no data is modified.