1-2 修改删除

1.update

db.user.update({name:"chengcheng"},{$set:{"name":"jiangwei"}})

如果不加$set,会将那条数据完全替换

db.user.update({name:"jiangwei"},{name:"huan"}})

2.remove删除某条数据

db.collectionName.remove(condition)

db.user.remove({name:'li'})

2.1justOne:true只删除一条数据

db.user.remove({name:"shanshan"},{justOne:true})

3.更新内嵌数组中某条数据

//user
//更新cartList中id等于1002这条数据,将num设置为2
{
  _id: 4,
  cartList: [
     { id: 1001, num: 1, name: "手机" },
     { id: 1002, num: 1, name: "电脑" },
     { id: 1003, num: 1, name: "平板" }
  ]
}

db.user.update({_id:4,"cartList.id":1001},{$set:{"cartList.$.num":2}})