You can most definitely use any type of database-specific function you wish with Hibernate HQL (and JPQL as long as Hibernate is the provider). You simply have to tell Hibernate about those functions. In 3.3 the only option for that is to provide a custom Dialect and register the function from the Dialect's constructor. If you take a look at the base Dialect class you will see lots of examples of registering functions. Usually best to extend the exact Dialect you currently use and simply provide your extensions (here, registering the function).
An interesting note is that Oracle does not classify regexp_like as a function. They classify it as a condition/predicate. I think this is mostly because Oracle SQL does not define a BOOLEAN datatype, even though their PL/SQL does and I would bet regexp_like is defined as a PL/SQL function returning BOOLEAN...
Assuming you currently use Oracle10gDialect, you would do:
public class MyOracle10gDialect extends Oracle10gDialect {
public Oracle10gDialect() {
super();
registerFunction(
"regexp_like",
new StandardSQLFunction( "regexp_like", StandardBasicTypes.BOOLEAN )
);
}
}
I cannot remember if the HQL parser likes functions returning booleans however in terms of being a predicate all by itself. You may instead have to convert true/false to something else and check against that return:
public class MyOracle10gDialect extends Oracle10gDialect {
public Oracle10gDialect() {
super();
registerFunction(
"regexp_like",
new StandardSQLFunction( "regexp_like", StandardBasicTypes.INTEGER ) {
@Override
public String render(
Type firstArgumentType,
List arguments,
SessionFactoryImplementor factory) {
return "some_conversion_from_boolean_to_int(" +
super.render( firstArgumentType, arguments, factory ) +
")";
}
}
);
}
}
