Named Queries and Null parameters

Question

I am trying to use null values in the where clause of named query. I have a named query defined in my Workbench (Toplink 9.0.4) and the where claus looks like this.
WHERE PERSON.LAST_NAME=#lastName
If a pass in a value for lastName, say "Jones", Toplink correctly creates a where clause in single quotes:
WHERE PERSON.LAST_NAME='Jones'
However, if I pass in a null value for lastName, Toplink generates this:
WHERE PERSON.LAST_NAME=NULL
This will never select anything, because a value can never "equal" null, but rather it IS NULL or it isn't.
Any ideas out there on how I could get Toplink to substitute "IS NULL" of "=NULL" in such situations?

Answer 1

Different databases handle = null differently. I assume you are on DB2?
You can force a query to dynamically generate its SQL, to ensure that IS NULL is used.
query.setShouldPrepare(false);
In the Mapping Workbench for the query click on 'Advanced Properties' and un-click 'Prepare SQL Once'.
The database may also process the = null correctly if binding is used, but I'm not sure on this.