JPA 标准构建器 where 语句

Question

我想在我的 CriteriaQuery 中实现以下 where 语句。

  (Event.time >= NOW() 
     OR (Event.time >= '$clubHours' && (`EventSelectType`.`type`='cafe' || `EventSelectType`.`type`='DJ')) 
     OR (Event.endtime >= NOW() && (`EventSelectType`.`type`='festival' OR `EventSelectType`.`type`='dj' OR `EventSelectType`.`type`='cafe')))

我尝试了以下；

eQr.where(
        cB.or(
            cB.or(
                    cB.greaterThanOrEqualTo(eventRoot.<Date>get("time"), curDate)   
                ),
            cB.or(
                    cB.and(
                    cB.greaterThanOrEqualTo(eventRoot.<Date>get("time"), cal.getTime())
                    ),
                        cB.or(
                                cB.equal(eventType.<String>get("type"), "cafe"),
                                cB.equal(eventType.<String>get("type"), "DJ")
                                )
                ),
            cB.or(
                    cB.and(
                    cB.greaterThanOrEqualTo(eventRoot.<Date>get("endtime"), curDate)
                    ),
                        cB.or(
                                cB.equal(eventType.<String>get("type"), "festival"),
                                cB.equal(eventType.<String>get("type"), "DJ"),
                                cB.equal(eventType.<String>get("type"), "cafe")
                                )
                )
        ),
        cB.equal(eventRoot.<Integer>get("id"), eventID),
        cB.equal(eventRoot.<Integer>get("active"), 1)
        );

但这一切都产生了一个大的 OR 语句

(event0_.time>=? or event0_.time>=? or eventselec13_.type=? or eventselec13_.type=? or event0_.endtime>=? or eventselec13_.type=? or eventselec13_.type=? or eventselec13_.type=?)

我怎样才能得到我正在寻找的结果？

编辑

我现在有这个

Predicate eventTypeIscafeORDJ = cB.or(
        cB.equal(eventType.<String>get("type"), "cafe"),
        cB.equal(eventType.<String>get("type"), "DJ")
    );
Predicate eventTypeIsFestivalDJORCafe = cB.or(
        cB.equal(eventType.<String>get("type"), "cafe"),
        cB.equal(eventType.<String>get("type"), "DJ"),
        cB.equal(eventType.<String>get("type"), "festival")
        );

    Predicate timeGreaterOrEqualTo = cB.greaterThanOrEqualTo(eventRoot.<Date>get("time"), cal.getTime());
    Predicate endTimeGreaterOrEqualTo = cB.greaterThanOrEqualTo(eventRoot.<Date>get("endtime"), curDate);
    Predicate equalToId = cB.equal(eventRoot.<Integer>get("id"), eventID);

    eQr.where(timeGreaterOrEqualTo, cB.or( cB.and( timeGreaterOrEqualTo, eventTypeIscafeORDJ ), cB.and(endTimeGreaterOrEqualTo, eventTypeIsFestivalDJORCafe )), equalToId);

哪些输出

where event0_.time>=? and (event0_.time>=? and (eventselec13_.type=? or eventselec13_.type=?) or event0_.endtime>=? and (eventselec13_.type=? or eventselec13_.type=? or eventselec13_.type=?)) and event0_.id=633188

但它必须是

where (event0_.time>=? OR (event0_.time>=? and (eventselec13_.type=? or eventselec13_.type=?)) or (event0_.endtime>=? and (eventselec13_.type=? or eventselec13_.type=? or eventselec13_.type=?))) and event0_.id=633188

它仍然不是我想要的，我似乎无法让它按照我想要的方式工作。

Answer 1

从你明显的第一个问题开始：

Event.time >= '$clubHours' && (`EventSelectType`.`type`='cafe' || `EventSelectType`.`type`='DJ')) 

这应该被构造为

cB.and(
    cB.greaterThanOrEqualTo(eventRoot.<Date>get("time"), cal.getTime()), 
    cB.or(
        cB.equal(eventType.<String>get("type"), "cafe"),
        cB.equal(eventType.<String>get("type"), "DJ")
    )
), ...

相反，你有：

cB.and(
    cB.greaterThanOrEqualTo(eventRoot.<Date>get("time"), cal.getTime())
),
cB.or(
    cB.equal(eventType.<String>get("type"), "cafe"),
    cB.equal(eventType.<String>get("type"), "DJ")
)

因此，基本上，您需要确保查看括号而不是缩进，以便了解您的代码在做什么。作为旁注，您最好逐步构建此谓词，以便您的代码更易于阅读和理解。例如：

Predicate eventTypeIscafeORDJ = cB.or(
    cB.equal(eventType.<String>get("type"), "cafe"),
    cB.equal(eventType.<String>get("type"), "DJ")
);
Predicate timeGreaterOrEqualTo = cB.greaterThanOrEqualTo(eventRoot.<Date>get("time"), cal.getTime());
eQr.where( cB.and( timeGreaterOrEqualTo, eventTypeIscafeORDJ ) );

数据库几乎总是代码中较慢的部分，优化器可能会输出相同的运行时或任何一组代码，因此您应该让自己和他人更轻松。此外，这是调试编码问题的久经考验的方法，尤其是当您看到所有这些括号时。