Is field value Null
Is field value Null ( aField ) : Boolean
| Parameter | Type | Description | |
|---|---|---|---|
| aField | Field | → | Field to be evaluated |
| Function result | Boolean | ← | True = field is NULL, False = field is not NULL |
Description
The Is field value Null command returns True if the field designated by the aField parameter contains the NULL value, and False otherwise.
The NULL value is used by the SQL kernel of 4D. For more information, refer to the 4D SQL Reference manual.
The value returned by this command is only meaningful if the "Map NULL values to blank values" option is not checked in the field definition of the Structure editor. Otherwise, it always returns False.
Note: This command cannot be used with objects and object properties. Null values in object fields are handled through the Null command.
See also
Properties
| Command number | 964 |
| Thread safe | ✓ |