Boolean operators in the WHERE clause

Question

I'd like to create an operator which would allow me to use the following syntax in the where clause:
select 1 from dual where iplike('172.16.0.128', '*.*.*.*');
I've created a function (iplike_bool_fn) to implement my desired check, and attempted to bind an operator to it:
create or replace operator iplike binding(varchar,varchar) return boolean using iplike_bool_fn;
The binding fails with: ORA-06553: PLS-201: identifier 'OPENNMS.BOOLEAN' must be declared
I acknowledge the 'no boolean in SQL' issue, however, I don't understand how several built-in operators appear to work fine this way:
select 1 from dual where REGEXP_LIKE('test','test');
Is there a way to construct a user defined operator that will allow this syntax?

Answer 1

SQL does not recognise the Boolean datatype returning TRUE/FALSE as a valid datatype. Your function would have to return a value of, say, 0 or 1 and then you compare the result of the function to those values to determine your match or not.
Alternatively, depending on your database version, you could use regular expressions (REGEXP_LIKE) to do your comparison, which would remove the need to call any PL/SQL code (which degrades the performance of SQL).
PS. So in short, the answer to your question is No, you can't construct your own type of function like this.
Message was edited by:
blushadow