MongoDB Learning (ii) MONGODB common commands

One, DB data operation

    (1) Help view command prompt      help      db.help ();      Db.yourColl.help ();      Db.youColl.find (). Help ();      Rs.help ();             (2) switch/CREATE database use      Yourdb;      When a collection (table) is created, the current database (3) is automatically created to            query all databases      show DBS;             (4) Delete the currently used database      db.dropdatabase ();             (5) Cloning the database      db.clonedatabase ("127.0.0.1") from the designated host      ; Clones data from the database on the specified machine to the current database             (6) Copy the specified database data from the specified machine to a database      db.copydatabase ("MyDB", "temp", "127.0.0.1");       Copy the MyDB data from the native to the temp database             (7) to fix the current database      db.repairdatabase ();             (8) View the currently used database      db.getname ();      DB;      The DB and GetName methods are the same effect and can query the currently used database             (9) to display the current DB status      db.stats ();             (10) Current DB version      db.version ();             (11) View the current DB link machine address      db.getmongo ();  

2. Collection Aggregation Collection

    (1) Create a clustered collection (table)      db.createcollection ("Collname", {size:20, Capped:5, max:100});             (2) A clustered Set (table)      db.getcollection ("account") with the specified name;             (3) Get all the aggregation sets of the current DB      db.getcollectionnames ();             (4) Displays the status of all clustered indexes of the current DB      db.printcollectionstats ();  

3. User-related

    (1) Add a user      Db.adduser ("name");      Db.adduser ("UserName", "pwd", true); #用户, password, whether read            -only (2) database authentication, security mode      Db.auth ("UserName", "pwd");            (3) Show all current user show users      ;             (4) Delete user      Db.removeuser ("UserName");  

4. Other

    (1) Error message before query      db.getpreverror ();             (2) Clear Error Record      db.reseterror ();  

Second, collection aggregation set operation

1. View aggregate Collection basic information

    Db.yourColl.help (); #查看帮助      Db.yourColl.count (); #查询当前集合的数据条数      db.yourColl.dataSize (); #查看数据空间大小      Db.yourColl.getDB (); Get the DB Db.yourColl.stats () of the current aggregation set,      #得到当前聚集的状态      db.yourColl.totalSize (); #得到聚集集合总大小      Db.yourColl.storageSize (); #聚集集合储存空间大小      db.yourColl.getShardVersion (); #Shard版本信息      db.yourColl.renameCollection ("users"); #聚集集合重命名      Db.yourColl.drop (); #删除当前聚集集合  

2. Aggregate collection queries

    (1) query all Records db.userInfo.find ();      Equivalent to: SELECT * from UserInfo; The default is 20 records per page, and you can query the next page of data with the IT iteration command when the display is not displayed.            Note: Type the IT command cannot take ";" but you can set the size of the data displayed per page, with dbquery.shellbatchsize = 50, so that each page shows 50 records.      (2) Duplicate data db.userInfo.distinct ("name") for a column in the current collection after the query is removed;             Will filter out the same data in name equivalent to: Select Distict name from UserInfo;      (3) Query age = 22 Record Db.userInfo.find ({"Age": 22});             Equivalent to: SELECT * from userInfo where age = 22;      (4) Query age > 22 record Db.userInfo.find ({age: {$gt: 22}});             Equivalent to: SELECT * from UserInfo where age > 22;      (5) Query age < 22 record Db.userInfo.find ({age: {$lt: 22}});             Equivalent to: SELECT * from UserInfo where age < 22;      (6) Query the record Db.userInfo.find ({age: {$gte: 25}) of age >= 25;             Equivalent to: SELECT * from UserInfo where age >= 25;             (7) Query the record Db.userInfo.find ({age: {$lte: 25}) of age <= 25; (8) Query age >= 23 and age <=-Db.userInfo.find ({age: {$gte: $, $lte: 26}});      (9) The query name contains MONGO data Db.userInfo.find ({name:/mongo/});             Equivalent to a percent of select * from UserInfo where the name like '%mongo% ';      (10) Query the name Db.userInfo.find ({name:/^mongo/}) beginning with MONGO;             SELECT * from UserInfo where name is like ' mongo% ';      (11) Query the specified column name, age data Db.userInfo.find ({}, {name:1, age:1});      Equivalent to: Select Name, age from UserInfo;             Of course name can also be used with true or false, as in the case of Ture River Name:1 effect, if False is to exclude name, display column information other than name.      (12) Query the specified column name, age data, age > Db.userInfo.find ({age: {$gt: +}}, {name:1, age:1});             Equivalent to: Select Name, age from UserInfo where age > 25;      (13) Sorted by age Ascending: Db.userInfo.find (). Sort ({age:1});             Descending: Db.userInfo.find (). Sort ({Age:-1});      (14) Query name = Zhangsan, age = 22 Data db.userInfo.find ({name: ' Zhangsan ', age:22});             Equivalent to: SELECT * from userInfo where name = ' Zhangsan ' and "age = ' 22 ';      (15) Query the first 5 data db.userInfo.find (). Limit (5); Equivalent to: SELECT Top 5 * from UserInfo;      (16) Query 10 after the data Db.userInfo.find (). Skip (10);             Equivalent to: SELECT * from UserInfo where ID not in (select Top ten * from UserInfo);      (17) query data between 5-10 db.userInfo.find (). Limit (Ten). Skip (5);      Can be used for pagination, limit is Pagesize,skip is the number of pages *pagesize () or with the query Db.userInfo.find ({$or: [{age:22}, {age:25}]});             Equivalent to: SELECT * from UserInfo where is age = 25      (19) Query the first Data Db.userInfo.findOne ();      Equivalent: SELECT top 1 * from UserInfo;             Db.userInfo.find (). limit (1);      (20) Query the number of record bars for a result set Db.userInfo.find ({age: {$gte: +}}). Count ();             Equivalent to: SELECT COUNT (*) from UserInfo where age >= 20;      (+) exists db.userInfo.find ({sex: {$exists: true}}). Count ();   Equivalent to: SELECT COUNT (Sex) from userInfo;

3. Index

    (1) CREATE index      db.userInfo.ensureIndex ({name:1});      Db.userInfo.ensureIndex ({name:1, TS:-1});             (2) Query the current aggregate collection all Indexes      db.userInfo.getIndexes ();             (3) View total index record size      db.userInfo.totalIndexSize ();             (4) Read all index information of the current set      db.users.reIndex ();             (5) Delete the specified index      db.users.dropIndex ("Name_1");             (6) Delete all Index index      db.users.dropIndexes ();  

4. Modify, add, and delete collection data

    (1) Add Db.users.save ({name: ' Zhangsan ', age:25, sex:true});      The data column of the added data is not fixed, according to the added data (2) Modify Db.users.update ({age:25}, {$set: {name: ' ChangeName '}}, False, True);             Equivalent to: Update users set name = ' ChangeName ' where age = 25;      Db.users.update ({name: ' Lisi '}, {$inc: {age:50}}, False, True);             Equivalent to: Update users set age = Age + where name = ' Lisi ';      Db.users.update ({name: ' Lisi '}, {$inc: {age:50}, $set: {name: ' HoHo '}}, False, True);             Equivalent to: Update users set age = Age +, name = ' HoHo ' WHERE name = ' Lisi ';             (3) Delete db.users.remove ({age:132}); (4) Query modification Delete db.users.findAndModify ({query: {age: {$gte: +}}, Sort: {Age:-1}, update: {             $set: {name: ' A2 '}, $inc: {age:2}}, remove:true}); Db.runcommand ({findandmodify: "Users", query: {age: {$gte: +}}, Sort: {Age:-1}, UPDATE: {$set: {name: ' A2 '}, $inc: {age:2}},         Remove:true});   

  Third, statement block operation

    (1) Simple Hello World print ("Hello world!"); This notation calls the print function, and writes "Hello world!" directly      The effect is the same; (2) Convert an object to a JSON Tojson (new object ());             Tojson (New Object (' a '));      (3) Loop add data for (var i = 0; i < i++) {Db.users.save ({name: "u_" + I, age:22 + i, sex:i% 2});      };      This adds 30 data to the loop, and can also omit the notation for (var i = 0; i < i++) Db.users.save ({name: "u_" + I, age:22 + i, sex:i% 2}); It is also possible, when you use Db.users.find () query, display multiple data and can not be displayed on a page, the use of it to view the next page of information; (4) Find cursor query var cursor = DB.USERS.F      IND ();       while (Cursor.hasnext ()) {Printjson (Cursor.next ());      This will query all the users information, as well as the var cursor = Db.users.find ();      while (Cursor.hasnext ()) {Printjson (cursor.next);}      You can also omit the {} number (5) foreach Iteration Loop Db.users.find (). foreach (Printjson);      A function must be passed in foreach to handle the data information for each iteration (6) The Find cursor is treated as an array of var cursor = Db.users.find ();      CURSOR[4]; The data that gets the subscript index 4 is now availableTo be treated as an array, the length of it can be obtained: Cursor.length (); or cursor.count ();             That way we can also display the data for (var i = 0, Len = c.length (), I < Len, i++) Printjson (C[i]) in the loop.      (7) Convert the Find cursor to the tuple var arr = Db.users.find (). ToArray ();      Printjson (arr[2]); Use the ToArray method to convert it to an array (8) Customizing our own query results to show only age <= 28 and only the age of this column of data Db.users.find ({age: {$lte: +}}, {age      : 1}). ForEach (Printjson);      Db.users.find ({age: {$lte: +}}, {age:true}). ForEach (Printjson);             Excludes Age's Column db.users.find ({age: {$lte: +}}, {Age:false}). ForEach (Printjson);      (9) The Foreach transfer function displays information Db.things.find ({x:4}). foreach (function (x) {print (Tojson (x));});   As described above, foreach needs to pass a function that takes a parameter, that is, the object that is currently looping, and then processes the incoming parameter information in the function weight.

MongoDB Learning (ii) MONGODB common commands