function
Library: Database access (OMDB)
Import : omdb.xmd |
Returns: TRUE if the field value is SQL NULL, or FALSE otherwise. |
define external switch function db.is-null value db.field field
Argument definitions
Use db.is-null to check whether or not a field in a database record contains a NULL value.
The database connection represented by db.database must be:
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).
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.
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