Mongodb简单的操作

一、插入

   One和Many可加可不加加上会显示 
{
        "acknowledged" : true,
        "insertedIds" : [
                ObjectId("6257cd785e88cde95125012b"),
                ObjectId("6257cd785e88cde95125012c")
        ]
}
   不加
WriteResult({ "nInserted" : 1 })


db.a.insertOne({
   name: "haha",
   from: {
     country: "China",
     province: "Guangdon"
     }
 })      #插入单个的

 db.a.insertMany([
  {name: "haha",
   from: {
     country: "China",
     province: "Guangdon"
     }
  },
   {name: "haha",
   from: {
     country: "China",
     province: "Guangdon"
     }
  }
 ])    #插入多条数据

 

二、查看数据

db.a.find({"find.name" : "haha"})
db.a.find({ "from.country" : "haha" })  #两个都可以查到信息

db.a.find(
  {
  },{from: 0}

)      #from的值不会显示

三、数组查询

db.a.insert([
   { "name": "Apple", color: ["red","yellow"]},
   { "name": "Apple", color: ["red","green"]}
 ])

db.a.find({$or: [{color: "red"},{color: "green"}]})#查看数组，下面两行是结果
{ "_id" : ObjectId("6257caaf5e88cde951250126"), "name" : "Apple", "color" : [ "red", "yellow" ] }
{ "_id" : ObjectId("6257caaf5e88cde951250127"), "name" : "Apple", "color" : [ "red", "green" ] } 

 四、聚合函数

$match            过滤                   相当于sql的where
$project          投影                   相当于sql的AS
$sort             排序                   相当于sql的order by
$group            分组                   相当于sql的group by
$skip/$limit      结果限制                相当于sql的SKIP/limite
$lookup           做外链接                相当于sql的LEFT OUTER JOIN