I am struggling to create a query using the Criteria API. The following SQL query returns the result that I need:
SELECT * FROM MODEL WHERE MANUFACTURER_ID = 1 AND SHORTNAME LIKE '%SF%' OR LONGNAME LIKE '%SF%';
I have written the following code using the criteria API:
public List<Model> findAllByManufacturer(Manufacturer manufacturer,
String pattern) {
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Model> cq = cb.createQuery(Model.class);
Root<Model> m = cq.from(Model.class);
cq.select(m);
Join<Model, Manufacturer> mf = m.join("manufacturer");
Predicate p = cb.equal(mf.get("id"), manufacturer.getId());
p = cb.and(cb.like(cb.upper(m.<String>get("shortName")),
pattern.toUpperCase()));
p = cb.or(cb.equal(cb.upper(m.<String>get("longName")),
pattern.toUpperCase()));
cq.where(p);
return em.createQuery(cq).getResultList();
}
When I think about it logically, it should work:
Predicate p = cb.equal(mf.get("id"), manufacturer.getId());
WHERE MANUFACTURER_ID = 1
p = cb.and(cb.like(cb.upper(m.<String>get("shortName")),
pattern.toUpperCase()));
AND SHORTNAME LIKE '%SF%'
p = cb.or(cb.equal(cb.upper(m.<String>get("longName")),
pattern.toUpperCase()));
OR LONGNAME LIKE '%SF%'
The qu开发者_如何学JAVAery does properly run in that I am not getting any errors, it just is not returning any results. Any clue on where I went wrong are very much appreciated!
Have you checked the generated SQL?
You're building a predicate and assigning it to p
, but then you're creating another one and assign it to the same p
variable.
I think it should rather be:
Predicate predicateOnManufacturerId = cb.equal(mf.get("id"),
manufacturer.getId());
Predicate predicateOnShortName = cb.like(cb.upper(m.<String>get("shortName")),
pattern.toUpperCase()));
Predicate predicateOnLongName = cb.equal(cb.upper(m.<String>get("longName")),
pattern.toUpperCase()));
Predicate p = cb.or(cb.and(predicateOnManufacturerId,
predicateOnShortName),
predicateOnLongName);
cq.where(p);
Also, why don't you use the meta-model of your entities:
Join<Model, Manufacturer> mf = m.join(Model_.manufacturer);
... cb.equal(mf.get(Manufacturer_.id);
...
It would be more type-safe, and you would detect incorrect queries at compilation time rather than runtime.
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