db.is-null

function

Library: Database access (OMDB)
Import : omdb.xmd

Returns: TRUE if the field value is SQL NULL, or FALSE otherwise

Declaration

define external switch function db.is-null value db.field field

Argument definitions

field: is a db.field object associated with a field in the current record in an active SQL query record set.

Purpose

Use db.is-null to check whether or not a field in a database record contains a NULL value.

Requirements

The database connection represented by db.database must be:

open (else external exception OMDB209)
in scope (else external exception OMDB103)

The db.field object field must be associated with a query (else external exception OMDB302).

The data cursor must be positioned on an existing row (else external exception OMDB205).

Usage Notes

The data cursor points to the record set's currently active row.

The function uses a db.field shelf variable containing a record set created by db.query, db.execute, or db.streaming-execute.

Function db.reader with the optional argument null provides another way of handling NULL field values in the record set.

Example

         repeat
           exit unless db.record-exists my-record
  
           output '<record%n'
           repeat over my-record as my-field
              output '%_%_' || key of my-field || '="' || db.reader of my-field || '"%n'
                 unless db.is-null my-field
           again
           output '/>%n'
  
           db.move-record my-record
         again

Related Topics

Other Library Functions