mongodb创建、更新、删除

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 = 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"})