MongoDB basic commands are used

After the successful start of MongoDB, and then open a command line window input MONGO, you can do some of the database operations.

Enter help to see the basic Operations Command:

Show DBS: Display Database list
Show Collections: Displays a collection in the current database (similar to a table in a relational database)
Show Users: Show user

Use <db name>: Switch the current database, which is the same as the meaning in Ms-sql
Db.help (): Show database Operations Command with a lot of commands
Db.foo.help (): Displays the set Operation command, as well as a lot of commands, Foo refers to the current database, a collection called Foo, not the real meaning of the command
Db.foo.find (): Data lookup for the Foo collection in the current database (all data is listed because there are no conditions)
Db.foo.find ({a:1}): Looks for the Foo collection in the current database, provided the data has a property called a, and A has a value of 1

MongoDB does not have a command to create a database, but there are similar commands.

For example, if you want to create a "myTest" database, run the use myTest command first, then do something (such as: db.createcollection (' user ')) so that you can create a database called "MyTest".

Database Common Commands

1. Help View command Prompt

Help

Db.help ();

Db.yourColl.help ();

Db.youColl.find (). Help ();

Rs.help ();

2. Switch/CREATE Database

Use Yourdb; The current database is created automatically when a collection (table) is created

3. Query all databases

Show DBS;

4. Delete the currently used database

Db.dropdatabase ();

5. Cloning a database from a specified host

Db.clonedatabase ("127.0.0.1"); Clones data from a database on a 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 native mydb data to the TEMP database

7. Repairing the current database

Db.repairdatabase ();

8. View the database currently in use

Db.getname ();

db The DB and GetName methods are the same effect and can query the currently used database

9. Display the current DB status

Db.stats ();

10. Current DB version

Db.version ();

11. View the current DB link machine address

Db.getmongo ();

Collection Aggregation Collection

1. Create a Clustered collection (table)

Db.createcollection ("Collname", {size:20, Capped:5, max:100});

2. Get a clustered collection with the specified name (table)

Db.getcollection ("account");

3. Get all the aggregation sets of the current DB

Db.getcollectionnames ();

4. Displays the status of all clustered indexes in the current DB

Db.printcollectionstats ();

User-related

1. Add a user

Db.adduser ("name");

Db.adduser ("UserName", "pwd123", true); Add user, set password, read-only

2, database authentication, security mode

Db.auth ("UserName", "123123");

3. Show all current users

Show Users;

4. Delete users

Db.removeuser ("UserName");
other
1, the error message before the query
Db.getpreverror ();
2. Clear the Error Record
Db.reseterror ();

View Aggregate collection basic information

1, check the help Db.yourColl.help ();

2, query the current collection of data bar number Db.yourColl.count ();

3, view data space size db.userInfo.dataSize ();

4. Get the DB Db.userInfo.getDB () where the current aggregation set resides;

5, get the current gathering state db.userInfo.stats ();

6, get the aggregate aggregate size db.userInfo.totalSize ();

7, aggregate storage space size db.userInfo.storageSize ();

8. Shard Version Information Db.userInfo.getShardVersion ()

9, Aggregation set rename Db.userInfo.renameCollection ("Users"); Rename UserInfo to users

10. Delete the current aggregation set Db.userInfo.drop ();

Clustered Collection Query

1. Check all records

Db.userInfo.find ();

Equivalent: 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 ";"

However, you can set the size of the data displayed on each page, using dbquery.shellbatchsize= 50, which shows 50 records per page.



2. Duplicate data for a column in the current clustered collection after the query is removed

Db.userInfo.distinct ("name");

Will filter out the same data in name

Equivalent: Select Distict name from UserInfo;



3. Check the record of age = 22

Db.userInfo.find ({"Age": 22});

Equivalent to: SELECT * from userInfo where age = 22;



4. Check the records of age > 22

Db.userInfo.find ({age: {$gt: 22}});

Equivalent to: SELECT * from UserInfo where >22;



5. Check the records of age < 22

Db.userInfo.find ({age: {$lt: 22}});

Equivalent to: SELECT * from UserInfo where <22;



6. Check the records of age >= 25

Db.userInfo.find ({age: {$gte: 25}});

Equivalent to: SELECT * from UserInfo where age >= 25;



7. Check the records of age <= 25

Db.userInfo.find ({age: {$lte: 25}});



8. Query age >= 23 and age <= 26

Db.userInfo.find ({age: {$gte: $lte: 26}});



9. Query the data containing MONGO in name

Db.userInfo.find ({name:/mongo/});

Equal to percent

SELECT * from UserInfo where name is like '%mongo% ';



10, query the name in the beginning of MONGO

Db.userInfo.find ({name:/^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 > 25

Db.userInfo.find ({age: {$gt: +}}, {name:1, age:1});

Equivalent to: Select Name, age from UserInfo where age >25;



13. Sort 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: selecttop 5 * from UserInfo;



16, query 10 after the data

Db.userInfo.find (). Skip (10);

Equivalent to: SELECT * from UserInfo where ID not in (

Selecttop * from UserInfo

);



17, query the data between 5-10

Db.userInfo.find (). Limit (Ten). Skip (5);

Can be used for pagination, limit is Pagesize,skip is the first few pages *pagesize



18, OR and query

Db.userInfo.find ({$or: [{age:22}, {age:25}]});

Equivalent to: SELECT * from UserInfo where is age = 25



19. Query the first piece of data

Db.userInfo.findOne ();

Equivalent: Selecttop 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;



21. Sort by a column

Db.userInfo.find ({sex: {$exists: true}}). Count ();

Equivalent to: SELECT COUNT (Sex) from userInfo;

Index

1. Create an index

Db.userInfo.ensureIndex ({name:1});

Db.userInfo.ensureIndex ({name:1, TS:-1});



2. Querying all indexes of the current aggregation collection

Db.userInfo.getIndexes ();



3. View Total index record size

Db.userInfo.totalIndexSize ();



4. Read all index information for the current collection

Db.users.reIndex ();



5. Delete the specified index

Db.users.dropIndex ("Name_1");



6. Delete all index indexes

Db.users.dropIndexes ();

Modify, add, and delete collection data

1. Add

Db.users.save ({name: ' Zhangsan ', age:25, sex:true});

Data column of the added data, not fixed, according to the data added



2. Modification

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: 25}},

Sort: {Age:-1},

Update: {$set: {name: ' A2 '}, $inc: {age:2}},

Remove:true

});



Db.runcommand ({findandmodify: "Users",

Query: {age: {$gte: 25}},

Sort: {Age:-1},

Update: {$set: {name: ' A2 '}, $inc: {age:2}},

Remove:true

});

Update or remove one of them is a required parameter; Additional parameters are optional.

Parameters


Detailed


Default value

Query


Query Filter Criteria


{}

Sort


If multiple documents conform to a query filter, the first-ranked object will be selected in the arrangement specified by the parameter, and the object will be manipulated


{}

Remove


If true, the selected object will be deleted before it is returned


N/A

Update


A Modifier object


N/A

New


If true, the modified object is returned instead of the original object. In the delete operation, the parameter is ignored.


False

Fields


See Retrieving a subset of fields (1.5.0+)


All fields

Upsert


Creates a new object if the query result is empty. Example (1.5.4+)


False

Statement block Operations

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 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 you can also omit the notation

> for (var i = 0; i < i++) Db.users.save ({name: "u_" + I, age:22 + i, sex:i% 2});

is also possible, when you use the 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.find ();

> while (Cursor.hasnext ()) {

Printjson (Cursor.next ());

}

This allows you to query all the users information, as well as to write

var cursor = Db.users.find ();

while (Cursor.hasnext ()) {Printjson (cursor.next);}

You can also omit the {} number



5. Foreach Iteration Loops

Db.users.find (). ForEach (Printjson);

A function must be passed in foreach to process data information for each iteration



6. Treat the Find cursor as an array

var cursor = Db.users.find ();

CURSOR[4];

Get the data for subscript index 4

Since it can be treated as an array, its length can be obtained: Cursor.length (); or cursor.count ();

So we can also display the data in a loop

for (var i = 0, Len = c.length (); i < Len; i++) Printjson (C[i]);



7. Convert the Find cursor to an array

> var arr = db.users.find (). ToArray ();

> Printjson (arr[2]);

To convert it to an array using the ToArray method



8. Customize our own query results

Only age <= 28 is displayed and only the Age column data is displayed

Db.users.find ({age: {$lte: +}}, {age:1}). ForEach (Printjson);

Db.users.find ({age: {$lte: +}}, {age:true}). ForEach (Printjson);

Exclude The Age 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));});

MongoDB basic commands are used