Checking for all null values in a field, record or array element

isblank()

Check for all null values in a field, record or array element

SYNTAX

isblank(field_id | record_id)

isblank(field_id[index] | record_id[index])

This function checks for null values, returning TRUE if all values found are null, otherwise FALSE. Null values are defined as follows:

Field type	Null value
Numeric	zero
Alpha	all spaces
Binary	all bytes binary zero

The fields or elements to be checked are determined from the arguments to the function, as follows:

field_id	All elements of the field
field_id[index]	The specified element of the field
record_id	All elements of all fields in a !record structure
record_id[index]	The specified element of all fields in the record whose dimension is greater than or equal to index.

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NOTES

• The behaviour of this function with fields that have more than one dimension is undefined.

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EXAMPLE

Test for an all null record before inserting it:

!file NamesFile "C:/Tim/SCULPTOR/ProgGen/testfiles/names"
!record TmpNames = NamesFile

!function OKInsert() {

     if (isblank(TmpNames)) {
          prompt "", \
               " Insert a record with all null values - are you sure? " \
                    button = " Yes " \
                    button = " No  ", INSERT_CONTINUE
     }

     NamesFile = TmpNames
     insert NamesFile re = INSERT_RE riu = INSERT_RIU traps = INSERT_TRAPS

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RELATED TOPICS

Data fields

Field dimensions