Basic syntax for MongoDB

The previous period of work because there is not much to play with MongoDB, learn its basic grammar, and now do a simple summary here.

1. I am in win platform above, start words more trouble, so I simply put the boot process to do a batch file

Startup scripts

: Start a mongodb batch file , under    the bin directory of MongoDB D:    CD " program Files"    cd mongodb\server\3.2\bin: where D disk below the data, The DB directory was created manually : Start with the parameter --auth (Enable user access):--dbpath(datastore path)    mongod. exe-- Auth--dbpath D:\data\db

2. Some simple basic syntax

#创建或者切换数据库use admin# Query Method Db.system.users.find () #格式化的查询结果db. Userinfo.find (). Pretty () query comparer equals {<key>:<value>} db.col.find ({"By": "Rookie Tutorial"}). Pretty () Where by = ' Rookie Tutorial 'less than {<key>:{$lt: <value>}} db.col.find ({"likes": {$lt: {)}). Pretty () where likes < 50less than or equal to {<key>:{$lte: <value>}} db.col.find ({"likes": {$lte: {)}). Pretty () where likes <= 50greater than {<key>:{$gt: <value>}} db.col.find ({"likes": {$gt: {)}). Pretty () where likes > 50greater than or equal to {<key>:{$gte: <value>}} db.col.find ({"likes": {$gte: {)}). Pretty () where likes >= 50not equal to {<key>:{$ne: <value>}} db.col.find ({"likes": {$ne:}}). Pretty () where likes! = 50#查询年纪大于等于25的信息db. Userinfo.find ({"Age": {$gte: 25}}). Pretty () #查询age字段是String类型的记录.    The result set shown (the _id field is displayed by default) has only the user_name and age fields. Db.userinfo.find ({' Age ': {$type: 2}},{_id:0, "user_name": 1, "Age": 1}) #删除用户db. Dropuser (' Root ') #创建新的用户db. CreateUser ({' User ': ' Root ', ' pwd ': ' 000000 ', ' roles ': [{' Role ': ' ReadWrite ', ' db ': ' MyTest '}, {' Role ': ' ReadWrite ', ' db ': ' admin '}]}) #mongodb创建集合对象 db.xxx: Indicates that if XXX is present, insert data directly into it, and if it does not exist, create the corresponding collection # Insert data db. Collection_name.insert (document) Db.userinfo.insert ([{user_name:' 1 ', age:10, Sex:1},{user_name: ' 2 ', Age:10, sex:0}]) #mongodb更新语句更新单条语句 If the $set field does not exist and if the key does not exist, a new Db.item_info.update ({"item_id": "C9aea5ea-c29d-43ec-8205-fdb1e69934b7"},{$set: {"Item_name": "Test_update", "Test": "Test_add"}}) $unset keyword, delete the corresponding key value to remove the "Item_name", "test" the two key db.item_info.update ({"item_id": "C9aea5ea-c29d-43ec-8205-fdb1e69934b7"},{$unset: {"Item_name": "Test_update", "Test": "Test_add"}}) #mongodb更新语句更新多条语句db. Userinfo.updatemany ({"User_name": "1"}, {$set: {"user_name": "Nie"}}) #更新age字段<=The 20 field is Wewe value Db.userinfo.updateMany ({"Age": {$lte: $}}, {$set: {"Age": "Wewe"}}) #mongodb删除语句db. Userinfo.remove ({"User_name": "2"}) Delete all data Db.userinfo.remove ({}) #type $type operator is based on the Bson type to retrieve the matching data type in the collection and returns the result. //Querying the Age field is all records of type stringDb.userinfo.find ({"Age": {$type: 2}})

#MongoDB Sort () method using the sort () method to sort data in MongoDB, the sort () method can specify the sort field by parameter,and use 1 and-one to specify how to sort, where 1 is in ascending order, and-1 is for descending order. Db.userinfo.find ({},{_id:0, "user_name": 1, "Age": 1}). Sort ({"Age": 1}). Pretty () #创建索引 the option to add background:true when creating an index, Let the creation work execute in the backgroundDb.userinfo.ensureIndex ({"user_name": 1},{background:true})Maximum Range

• Cannot have more than 64 indexes in a collection
• Index name cannot exceed 125 characters in length
• A composite index can have a maximum of 31 fields

 #MongoDB Aggregation Functions

#删除 Db.item_info.deleteOne ({"Item_name": "Update_item_name"}) Db.item_info.find ({"Item_name": "Update_item_name"}). Count () DeleteresultDelete= Item.deletemany (Filters.eq ("Item_name", "Update_item_name")); System.out.println (Delete. Getdeletedcount ()); #mongodb语句explain>db.item_info.find ({}). Explain () {"Queryplanner" : {                "Plannerversion": 1,                "Namespace": "Test.item_info",                "Indexfilterset":false,                "Parsedquery" : {                        "$and" : [ ]                },                "Winningplan" : {                        "Stage": "Collscan",                        "Filter" : {                                "$and" : [ ]                        },                        "Direction": "Forward"                },                "Rejectedplans" : [ ]        },        "ServerInfo" : {                "Host": "Lenovo-niejian",                "Port": 27017,                "Version": "3.2.8",                "Gitversion": "Ed70e33130c977bda0024c125b56d159573dbaf0"        },        "OK": 1} #mongodb语句like (regular expression) if the retrieval needs to be case-insensitive, we can set the $options to $i. The following command looks for a case-insensitive string W3cschool.ccdb.posts.find ({post_text:{$regex:"W3cschool.cc", $options: "$i"}}) Db.item_info.find ({"item_id": {$regex:/c9aea5ea/}})

Basic syntax for MongoDB