createcriteria和or的區(qū)別

mybatis generator插件生成的example中，有createcriteria和or方法，他們有什么區(qū)別呢？

通過源碼，能很清楚的看出差別

createcriteria，當沒有規(guī)則時，則加入到現(xiàn)有規(guī)則，但有規(guī)則時，不再加入到現(xiàn)有規(guī)則，只是返回創(chuàng)建的規(guī)則

public Criteria createCriteria() {Criteria criteria = createCriteriaInternal();if (oredCriteria.size() == 0) { oredCriteria.add(criteria);}return criteria; }or，創(chuàng)建的規(guī)則，加入到規(guī)則集中，并且是or的關系

public Criteria or() { Criteria criteria = createCriteriaInternal(); oredCriteria.add(criteria); return criteria;}mybatis中Example的and和or

能用Example代碼解決的，我都不會去寫個SQL放在項目里。我希望讓代碼盡量優(yōu)雅、易讀，所以這里記錄一下關于MyBatis中Example的and和or的使用，主要是如下兩種場景：

where (條件1 and 條件2) or (條件3 and 條件4) where (條件1 and 條件2) and (條件3 or 條件4)where (條件1 and 條件2) or (條件3 and 條件4)

//條件1 and 條件2example.createCriteria().andEqualTo('isDeleted',IsDeleted.NOT_DELETED).andEqualTo('name', projectCatalogEntity.getName());//or (條件3 and 條件4)example.or(example.createCriteria().andEqualTo('isDeleted',IsDeleted.NOT_DELETED).andEqualTo('code', projectCatalogEntity.getCode()));

WHERE ( is_deleted = ? and name = ? ) or ( is_deleted = ? and code = ? )

where (條件1 and 條件2) and (條件3 or 條件4)

//條件1 and 條件2example.createCriteria().andEqualTo('isDeleted',IsDeleted.NOT_DELETED)).andEqualTo('parentId', projectCatalogEntity.getParentId());//and (條件3 or 條件4)example.and(example.createCriteria().andEqualTo('name', projectCatalogEntity.getName()).orEqualTo('code', projectCatalogEntity.getCode()));

WHERE ( is_deleted = ? and parent_id = ? ) and ( name = ? or code = ? )

以上為個人經(jīng)驗，希望能給大家一個參考，也希望大家多多支持好吧啦網(wǎng)。