MongoDB聚集索引基本操作

查看当前聚集的全部索引

> db.Account.getIndexes()

[

        {

                "name" : "_id_",

                "ns" : "ChatRoom.Account",

                "key" : {

                        "_id" : 1

                },

                "v" : 0

        }

]

 创建单列索引

> db.Account.ensureIndex({"UserName":1})

--1：ASC   -1：DESC

创建单列唯一索引

> db.Account.ensureIndex({"UserName" : 1},{"unique" : true})

创建单列唯一不重复索引

> db.Account.ensureIndex({"UserName" : 1},{"unique" : true，"dropDups" : true})

创建组合索引

> db.Account.ensureIndex({"UserName":1,"Email":1})
> db.Account.getIndexes()
[
        {
                "name" : "_id_",
                "ns" : "ChatRoom.Account",
                "key" : {
                        "_id" : 1
                },
                "v" : 0
        },
        {
                "_id" : ObjectId("4df7092607444568af61cffd"),
                "ns" : "ChatRoom.Account",
                "key" : {
                        "UserName" : 1
                },
                "name" : "UserName_1",
                "v" : 0
        },
        {
                "_id" : ObjectId("4df70dae07444568af61cffe"),
                "ns" : "ChatRoom.Account",
                "key" : {
                        "UserName" : 1,
                        "Email" : 1
                },
                "name" : "UserName_1_Email_1",
                "v" : 0
        }
]

删除索引

> db.Account.dropIndex({"UserName":1})
{ "nIndexesWas" : 3, "ok" : 1 }

> db.Account.dropIndex("UserName_1")
{ "nIndexesWas" : 3, "ok" : 1 }

删除聚集全部的索引

> db.Account.dropIndexes()
{
        "nIndexesWas" : 3,
        "msg" : "non-_id indexes dropped for collection",
        "ok" : 1
}
> db.Account.getIndexes()
[
        {
                "name" : "_id_",
                "ns" : "ChatRoom.Account",
                "key" : {
                        "_id" : 1
                },
                "v" : 0
        }
]

--删除全部索引不会删除默认索引