mongodb创建、更新、删除

来源：互联网发布：北京威锐达知乎编辑：程序博客网时间：2024/06/05 10:25

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向数组中添加新的值

> 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添加时，如果存在相同的值则不添加。

> 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 = 1010>> 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"})

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