MongoDB学习整理之更新(4)

来源：未知责任编辑：责任编辑发表时间:2014-04-20 03:42　点击:次

操作：db.t3.update({"userid":3},{$pop:{name:-1}})

更新后：{ "_id" : ObjectId("4fe098f08a6e072b231ca5ca"), "name" : [ "lzp", "xiaoping", "N1", "N2" ], "userid" : 3 }

操作：db.t3.update({"userid":3},{$pop:{name:1}})

更新后：{ "_id" : ObjectId("4fe098f08a6e072b231ca5ca"), "name" : [ "lzp", "xiaoping", "N1" ], "userid" : 3 }

8）$pull

用法：{$pull:{field:value}},从数组filed内删除一个等于value的值

更新前：{ "_id" : ObjectId("4fe098f08a6e072b231ca5ca"), "name" : [ "lzp", "xiaoping", "N1" ], "userid" : 3 }

操作：db.t3.update({"userid":3},{$pull:{name:"N1"}})

更新后：{ "_id" : ObjectId("4fe098f08a6e072b231ca5ca"), "name" : [ "lzp", "xiaoping" ], "userid" : 3 }

9）$pullAll

用法：{$pullAll:{field:value_array}},用法同$pull一样，可以一次删除数组内的多个值 www.2cto.com

更新后：{ "_id" : ObjectId("4fe098f08a6e072b231ca5ca"), "name" : [ "lzp", "xiaoping" ], "userid" : 3 }

操作：db.t3.update({"userid":3},{$pullAll:{name:["lzp", "xiaoping"]}})

更新后：{ "_id" : ObjectId("4fe098f08a6e072b231ca5ca"), "name" : [ ], "userid" : 3 }

10）$rename

用法：{$rename:{old_field_name:new_field_name}},完成字段的重命名

更新后：{ "_id" : ObjectId("4fe098f08a6e072b231ca5ca"), "name" : [ ], "userid" : 3 }

操作：db.t3.update({"userid":3},{$rename:{name:"alias"}})

更新后：{ "_id" : ObjectId("4fe098f08a6e072b231ca5ca"), "alias" : [ ], "userid" : 3 }