mongodb创建、更新、删除

全栈程序员站长

发布于 2022-07-08 20:02:17

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代码可运行

文章被收录于专栏：全栈程序员必看全栈程序员必看

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代码可运行

大家好，又见面了，我是全栈君。

1.插入操作

user = {"username":"lcq","sex":"man"}
db.user.insert(user)

2.更新

var lcq = db.user.findOne({"username":"lcq"}}
lcq.address = {"province":"shandong","location":"zoupin"}
lcq.haha = "hehhehe"
db.user.update({"username":"lcq"},lcq)


> db.user.update({"username":"lcq"},{$set:{"test":"test"}})
> db.user.findOne({"username":"lcq"})
{
        "_id" : ObjectId("55024de2849b70a4f670f413"),
        "address" : {
                "province" : "shandong",
                "location" : "zoupin"
        },
        "haha" : "afdfdfd",
        "sex" : "man",
        "test" : "test",
        "username" : "lcq"
}

> db.user.update({"username":"lcq"},{$unset:{"test":1}})

$unset删除某个字段

> lcq = db.user.findOne({"username":"lcq"})
{
        "_id" : ObjectId("55024de2849b70a4f670f413"),
        "address" : {
                "province" : "shandong",
                "location" : "zoupin"
        },
        "haha" : "afdfdfd",
        "sex" : "man",
        "username" : "lcq"
}
>
>
> lcq.count = 1
> db.user.update({"username":"lcq"},lcq)


> db.user.update({"username":"lcq"},{$inc:{"count":2}})

$inc设置某个字段自增

> db.user.update({"username":"lcq"},{$set:{"friends":['zhangsan']}})


> db.user.findOne()
{
        "_id" : ObjectId("55024de2849b70a4f670f413"),
        "address" : {
                "province" : "shandong",
                "location" : "zoupin"
        },
        "count" : 3,
        "friends" : [
                "zhangsan"
        ],
        "haha" : "afdfdfd",
        "sex" : "man",
        "username" : "lcq"
}


> db.user.update({"username":"lcq"},{$push:{"friends":'lisi'}})
>
> db.user.findOne()
{
        "_id" : ObjectId("55024de2849b70a4f670f413"),
        "address" : {
                "province" : "shandong",
                "location" : "zoupin"
        },
        "count" : 3,
        "friends" : [
                "zhangsan",
                "lisi"
        ],
        "haha" : "afdfdfd",
        "sex" : "man",
        "username" : "lcq"
}

$push向数组中加入新的值

> db.user.update({"username":"lcq"},{$addToSet:{"friends":'lisi'}})
>
> db.user.findOne()
{
        "_id" : ObjectId("55024de2849b70a4f670f413"),
        "address" : {
                "province" : "shandong",
                "location" : "zoupin"
        },
        "count" : 3,
        "friends" : [
                "zhangsan",
                "lisi"
        ],
        "haha" : "afdfdfd",
        "sex" : "man",
        "username" : "lcq"
}


> db.user.update({"username":"lcq"},{$addToSet:{"friends":'xiaoming'}})
>
>
> db.user.findOne()
{
        "_id" : ObjectId("55024de2849b70a4f670f413"),
        "address" : {
                "province" : "shandong",
                "location" : "zoupin"
        },
        "count" : 3,
        "friends" : [
                "zhangsan",
                "lisi",
                "xiaoming"
        ],
        "haha" : "afdfdfd",
        "sex" : "man",
        "username" : "lcq"
}
>

可见使用$addToSet加入时，假设存在同样的值则不加入。

> db.user.update({"friends":"lisi"},{$set:{"friends.$":"join"}})
>
>
>
> db.user.findOne()
{
        "_id" : ObjectId("55024de2849b70a4f670f413"),
        "address" : {
                "province" : "shandong",
                "location" : "zoupin"
        },
        "count" : 3,
        "friends" : [
                "zhangsan",
                "join",
                "xiaoming"
        ],
        "haha" : "afdfdfd",
        "sex" : "man",
        "username" : "lcq"
}

使用$符进行数组的定位，实现更新数组特定位置的值。

> lcq = db.user.findOne()
{
        "_id" : ObjectId("55024de2849b70a4f670f413"),
        "address" : {
                "province" : "shandong",
                "location" : "zoupin"
        },
        "count" : 3,
        "friends" : [
                "zhangsan",
                "join",
                "xiaoming"
        ],
        "haha" : "afdfdfd",
        "sex" : "man",
        "username" : "lcq"
}
>
>
> lcq.count = 10
10
>


> db.user.save(lcq)
>


> db.user.findOne()
{
        "_id" : ObjectId("55024de2849b70a4f670f413"),
        "address" : {
                "province" : "shandong",
                "location" : "zoupin"
        },
        "count" : 10,
        "friends" : [
                "zhangsan",
                "join",
                "xiaoming"
        ],
        "haha" : "afdfdfd",
        "sex" : "man",
        "username" : "lcq"
}

save方法在不存在时创建。存在时更新。

更加方便。

3.删除

> db.user.insert({"username":"zhangsan"})
> db.user.remove({"username":"zhangsan"})

发布者：全栈程序员栈长，转载请注明出处：https://javaforall.cn/115904.html原文链接：https://javaforall.cn

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原始发表：2022年1月2，如有侵权请联系 cloudcommunity@tencent.com 删除

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