MongoDB learning-command operations

[From: http://hi.baidu.com/jadmin/blog/item/c734ab589cc52bc69d82043b.html]

I. DB shell database operations

Database

1. Help to view command prompts
Help
DB. Help ();
DB. yourcoll. Help ();
DB. youcoll. Find (). Help ();
Rs. Help ();

2. Switch to/create a database
> Use yourdb;
When a table is created, the current database is automatically created.

3. query all databases
Show dBs;

4. Delete the currently used database
DB. dropdatabase ();

5. clone a database from a specified host
DB. clonedatabase ("127.0.0.1 ");
Clone the database data 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 of the local machine to the temp database.

7. Fix the current database
DB. repairdatabase ();

8. view the currently used database
DB. getname ();
DB;
The dB and getname methods have the same effect. You can query the currently used database.

9. display the current dB status
DB. Stats ();

10. Current DB version
DB. Version ();

11. view the address of the linked machine of the current DB

DB. getmongo ();

Collection aggregation set

1. Create an aggregation set (table)
DB. createcollection ("collname", {size: 20, capped: 5, Max: 100 });

2. Get the clustering set (table) with the specified name)
DB. getcollection ("account ");

3. obtain all the aggregation sets of the current dB.
DB. getcollectionnames ();

4. display the status of all clustered indexes of the current DB
DB. printcollectionstats ();

User-related

1. Add a user
DB. adduser ("name ");
DB. adduser ("username", "pwd123", true );
Add a user, set a password, and check whether the user is read-only

2. database authentication and security mode
DB. Auth ("username", "123123 ");

3. display all current users
Show users;

4. delete a user
DB. removeuser ("username ");

Others

1. query previous error messages
DB. getpreverror ();

2. Clear error records
DB. reseterror ();

2. Collection collection operation

View basic information about a collection

1. View help
DB. yourcoll. Help ();

2. query the number of data entries in the current set
DB. yourcoll. Count ();

3. view the data space size
DB. userinfo. datasize ();

4. Obtain the dB of the current collection.
DB. userinfo. getdb ();

5. Get the current cluster status
DB. userinfo. Stats ();

6. Get the total size of the aggregation set.
DB. userinfo. totalsize ();

7. Size of the storage space of the aggregation set
DB. userinfo. storagesize ();

8. Shard version information
DB. userinfo. getshardversion ()

9. Rename the clustering set
DB. userinfo. renamecollection ("users ");
Rename userinfo to users

10. Delete the current collection.
DB. userinfo. Drop ();

Aggregate collection Query
1. query all records
DB. userinfo. Find ();
Equivalent to: Select * From userinfo;
By default, 20 records are displayed on each page. If no record is displayed, you can use the IT iteration command to query data on the next page. Note: The it command cannot contain ";"
However, you can set the size of data displayed on each page. Use dbquery. shellbatchsize = 50 to display 50 records on each page.

2. query duplicate data of a column in the current clustering set after Removal
DB. userinfo. Distinct ("name ");
The same data in name is filtered out.
Equivalent to: Select distict name from userinfo;

3. query records with age = 22
DB. userinfo. Find ({"Age": 22 });
Equivalent to: Select * From userinfo where age = 22;

4. query records of age> 22
DB. userinfo. Find ({age: {$ GT: 22 }});
Equivalent to: Select * From userinfo where age> 22;

5. query records of age <22
DB. userinfo. Find ({age: {$ LT: 22 }});
Equivalent to: Select * From userinfo where age <22;

6. query records with age> = 25
DB. userinfo. Find ({age: {$ GTE: 25 }});
Equivalent to: Select * From userinfo where age> = 25;

7. query records of age <= 25
DB. userinfo. Find ({age: {$ LTE: 25 }});

8. query age> = 23 and age <= 26
DB. userinfo. Find ({age: {$ GTE: 23, $ LTE: 26 }});

9. query data whose name contains Mongo
DB. userinfo. Find ({Name:/Mongo /});
// Equivalent to %
Select * From userinfo where name like '% Mongo % ';

10. query names starting with Mongo
DB. userinfo. Find ({Name:/^ Mongo /});
Select * From userinfo where name like 'mongo % ';

11. query the name and age data of a specified Column
DB. userinfo. Find ({}, {Name: 1, age: 1 });
Equivalent to: Select name, age from userinfo;
Of course, "true" or "false" can be used for name. If "true" is used, "river name: 1" has the same effect. If "false" is used, "name" is excluded and column information other than "name" is displayed.

12. query the name and age data of a specified column. age> 25
DB. userinfo. Find ({age: {$ GT: 25 },{ name: 1, age: 1 });
Equivalent to: Select name, age from userinfo where age> 25;

13. sort by age
Ascending Order: DB. userinfo. Find (). Sort ({age: 1 });
Descending order: DB. userinfo. Find (). Sort ({age:-1 });

14. query data with name = zhangsan and age = 22
DB. userinfo. Find ({Name: 'hangsan', age: 22 });
Equivalent to: Select * From userinfo where name = 'hangsan' and age = '22 ';

15. query the first five data entries
DB. userinfo. Find (). Limit (5 );
Equivalent to: Select top 5 * From userinfo;

16. Query 10 data records later
DB. userinfo. Find (). Skip (10 );
Equivalent to: Select * From userinfo where id not in (
Select top 10 * From userinfo
);

17. query data between 5-10
DB. userinfo. Find (). Limit (10). Skip (5 );
It can be used for paging. limit is pagesize, and skip is the page * pagesize

18. Or and query
DB. userinfo. Find ({$ or: [{age: 22}, {age: 25}]});
Equivalent to: Select * From userinfo where age = 22 or age = 25;

19. query the first data entry.
DB. userinfo. findone ();
Equivalent to: Select top 1 * From userinfo;
DB. userinfo. Find (). limit (1 );

20. query the number of records in a result set
DB. userinfo. Find ({age: {$ GTE: 25}). Count ();
Equivalent to: Select count (*) from userinfo where age> = 20;

21. sort by 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. query all indexes of the current clustered set
DB. userinfo. getindexes ();

3. view the total index record size
DB. userinfo. totalindexsize ();

4. Read all index information of the current set
DB. Users. reindex ();

5. delete a specified index
DB. Users. dropindex ("name_1 ");

6. Delete All indexes
DB. Users. dropindexes ();

Modify, add, and delete Set Data
1. Add
DB. Users. Save ({Name: 'hangsan', age: 25, sex: true });
The data column of the added data is not fixed. The data column is subject 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 + 50 where name = 'lisi ';

DB. users. update ({Name: 'lisi'}, {$ Inc: {Age: 50}, $ set: {Name: 'hohoho'}, false, true );
Equivalent to: Update users set age = age + 50, name = 'hohoho' where name = 'lisi ';

3. Delete
DB. Users. Remove ({age: 132 });

4. query, modify, and 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 is a required parameter. Other parameters are optional.

Parameters
Details
Default Value
Query query filtering condition {}
Sort if multiple documents meet the query filtering conditions, the first object will be selected in the order specified by this parameter, and the object will be operated {}
If this parameter is set to true, the selected object will be deleted before return.
Update a modifier object N/
If new is true, the modified object is returned instead of the original object. This parameter is ignored during the delete operation. False
For fields, see retrieving a subset of fields (1.5.0 +) all fields.
If the query result is null, create a new object in upsert. Example (1.5.4 +) False

Statement block Operation
1. Simple Hello World
Print ("Hello world! ");
This method calls the print function and directly writes "Hello world! "The effect is the same;

2. convert an object to JSON
Tojson (new object ());
Tojson (new object ('A '));

3. Add data cyclically
> For (VAR I = 0; I <30; I ++ ){
DB. Users. Save ({name: "U _" + I, age: 22 + I, sex: I % 2 });
};
In this way, 30 pieces of data are added cyclically, and the brackets can also be omitted.
> For (VAR I = 0; I <30; I ++) dB. users. save ({name: "U _" + I, age: 22 + I, sex: I % 2 });
You can also use it to view information on the next page when you use dB. Users. Find () to query multiple data entries and cannot display one page;

4. Find cursor Query
> Var cursor = dB. Users. Find ();
> While (cursor. hasnext ()){
Printjson (cursor. Next ());
}
In this way, all users information can be queried.
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 );
In foreach, a function must be passed to process the data information of each iteration.

6. process the find cursor as an array
VaR cursor = dB. Users. Find ();
Cursor [4];
Obtain the data with the subscript index 4.
Since it can be processed as an array, We can get its length: cursor. Length (); or cursor. Count ();
In this way, we can also display data cyclically.
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]);
Convert toarray to an array

8. customize our own query results
Only show age <= 28 and only show age data
DB. Users. Find ({age: {$ LTE: 28 },{ age: 1}). foreach (printjson );
DB. Users. Find ({age: {$ LTE: 28 },{ age: true}). foreach (printjson );
Exclude age Columns
DB. Users. Find ({age: {$ LTE: 28 },{ age: false}). foreach (printjson );

9. foreach transfer function display information
DB. Things. Find ({X: 4}). foreach (function (x) {print (tojson (x ));});
As mentioned above, foreach needs to pass a function. The function will accept a parameter, that is, the object of the current loop, and then process the input parameter information in the function weight.