Question

I am using oracle 10g and hibernate 3.3.2. I have used regular expression in sql before, now for the first time I am using it in HQL.

Query query = getSession().createQuery("From Company company 
where company.id!=:companyId and 
regexp_like(upper(rtrim(ltrim(company.num))), '^0*514619915$' )");

This is my hql, when i run it without regex_like function it runs as expected. But I am not able to execute it with regex_like expression.

It says..

nested exception is org.hibernate.hql.ast.QuerySyntaxException:
unexpected AST node: ( near line 1, column 66…..

Kindly help, how can I use regex_like in hibernate native query? OR some other alternative to do so.

Answer 1

Actually, you can’t compare the result of REGEXP_LIKE to anything except in conditional statements in PL/SQL.

Hibernate seems to not accept a custom function without a returnType, as you always need to compare the output to something, i.e:

REGEXP_LIKE('bananas', 'a', 'i') = 1

As Oracle doesn’t allow you to compare this function’s result to nothing, I came up with a solution using case condition:

public class Oracle10gExtendedDialect extends Oracle10gDialect {

    public Oracle10gExtendedDialect() {
        super();
        registerFunction(
          "regexp_like", new SQLFunctionTemplate(StandardBasicTypes.BOOLEAN,
          "(case when (regexp_like(?1, ?2, ?3)) then 1 else 0 end)")
        );
    }

}

And your HQL should look like this:

REGEXP_LIKE('bananas', 'a', 'i') = 1

It will work 🙂