null

Syntax

tag[#] = NULL()

Arguments

tag: database variable

Meaning

Deletes an occurrence from tag (if it isn't part of a data dictionary field group). Subsequent elements all move upwards one position. If no occurrence number subscript [#] is specified (where # must be replaced by a number), NULL removes all occurrences from the tag.
However, if the tag is part of a field group as defined in the data dictionary, removing a specific occurrence means deleting the entire field group occurrence, not just of the indicated tag occurrence; and removing all occurrences of the specified tag means deleting all occurrences of the entire field group!
If you want to empty the contents of one specific occurrence of a specific tag in a data dictionary field group, then you can do this with the assignment: tag[#]=''.

If you're using an after-field adapl to update existing contents of a linked field with a new value, then first assign null to the linked field itself and only after that, assign null to the link reference field, otherwise the change might only become visible to the user when the record has been saved.
Note that you shouldn't use tag=NULL assignments if the tag is part of a dummy FACS database and you use the adapl to print to a Word template: this causes an error during printing. Instead, use tag='' to assign an empty value. (A dummy FACS database is a FACS declaration which only contains tags that do not exist in the referenced database: these tags can be used to collect data in some way, usually to be printed to a Word template.)

The round brackets for this function may be omitted. If they are used, they may not contain an argument.

Example 1

au[3]=NULL()

Result

The third author is deleted from the record.

Example 2

au=NULL

Result

All authors are deleted from the record.

See also

REPINS