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[#]=''.
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