mongodb

1.{userid:1, comments:[{id:1, content:"a"},{id:2, content:"b"}])

  要查询出结果集为 {userid:1, comments:[{id:1, contents:"a"}]} 

  现在的mongodb不能做到这点,

  要想达到同样的目的,可以将comments设为object类型,而不是数组

  {userid:1, comments:{id1:{content:"a"}, id2:{content:"b"}}} 

 查询的语句是db.user.find({userid:1},  {'comments.id1':1})

结果是{userid:1, comments:{id1:{content:"a"}}}

Insert mode

转载于:https://www.cnblogs.com/lujingwei002/archive/2010/12/24/1915838.html