Question

public class Entity {
private boolean suspended;

private String code;

@Type(type = "org.jadira.usertype.dateandtime.joda.PersistentDateTime")
@DateTimeFormat(style = "S-")
private DateTime validFrom;

@Type(type = "org.jadira.usertype.dateandtime.joda.PersistentDateTime")
@DateTimeFormat(style = "S-")
private DateTime validTill;
}

Meaning of query: "Is the code unique in given time validity?"

• 如何重写:

select count(o) from Entity o 
where o <> :this and o.code = :code and (
  (o.validFrom between :validFrom and :validTill and not o.suspended) or
  (o.validTill between :validFrom and :validTill and not o.suspended) or 
  (:validFrom between o.validFrom and o.validTill and not o.suspended)
)

Answer 1

CriteriaBuilder builder = em.getCriteriaBuilder();
CriteriaQuery<Entity> cQuery = builder.createQuery(Entity.class);
Root<Entity> root = cQuery.from(Entity.class);

Predicate pValid1 = builder.between(root.get("ValidFrom"), validFrom, validTill);
Predicate pValid2 = builder.between(root.get("ValidTill"), validFrom, validTill);
Predicate pValid3 = builder.and(builder.lessThan(root.get("validTill"), balidFrom),builder.greaterThan(root.get("ValidFrom",validfrom)));

Predicate pSuspend = builder.not(root.get("Suspended"),true);

ExecutableQuery qFinal = em.createQuery(cQuery.select(root).where(builder.and(pSuspend,builder.or(pValid1,pvalid2,pvalid3))))

它应当这样做。应当能够调整元数据目标,尽管我还没有这样做。

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