Question

I do have a static metamodel with a NUMBER (actually, BigDecimal, don’t ask why) column. Now I would like to do a LIKE query against that number column:

CriteriaBuilder cb;
cb.like(entity.get(Entity_.numbercol), "123%");

where entity.get(Entity_.numbercol) returns a Path<BigDecimal>. Naturally, I get a compile error: ...like(Expression<String>, ...) ... not applicable for the arguments (Path<BigDecimal>, ...)

Casting the column with .as(String.class) fails due to some Bug in JPA, but I don’t have the bug number at hands right now. It is not fixed in the latest version of JPA/Hibernate, though. Anyway, it results in a runtime exception about some invalid SQL statement being generated.

Now I just need a way to get the criteria API equivalent of the SQL

... WHERE numbercol LIKE '123%';

Searching for the topic already brought up the following responses, which don’t help because I have a static metamodel:
NHibernate – easiest way to do a LIKE search against an integer column with Criteria API? and JPA/Criteria API – Like & equal problem

Any ideas?

Thanks in advance
Dominik

Answer 1

No, it does not fail because of bug, it works as specified (for example in Javadoc):

Perform a typecast upon the expression, returning a new expression
object. This method does not cause type conversion: the runtime type
is not changed. Warning: may result in a runtime failure.

Method you use performs cast and you need conversion. In general there is no support to convert from BigDecimal to String in JPA.