Objective:
This article mainly records the DML operations of the main MongoDB Collection.
The Collection name in the second article is Yourcoll, and each operation initially contains two data
{ "_id": ObjectId ("5438df36309dca34635d4460"), "username":"name1", "Mail":"Name1@abc. com"},{ "_id": ObjectId ("5438df40309dca34635d4461"), "username":"name2", "Mail":"[email protected]", " Age": -}
A, C
- Db.collection.save ()
Db.yourcoll. Save ({ username: "Mayj", Mail: "Test@abc. com"})
Note:save operation if the document contains a primary key (_ID), to determine whether the primary key exists, if present, update the original record, if not present, insert a new record. The difference between insert and save is that if a document contains a primary key (_id) and exists, it does not handle processing and returns an error.
Second, R
- Db.collection.find ()
- Querying All records
Db.yourColl.find ();
Equivalent to MySQL
Select * from Yourcoll;
- Querying distinct duplicate data for a column
Db.yourcoll. distinct
Equivalent to MySQL
Select from
- Querying the AGE=28 data
Db.yourColl.find ({ ,})
Equivalent to MySQL
Select * from where = ;
- Query Age >20 data
db.yourcoll.find ({age: {$gt: 20
Equivalent to MySQL
* from yourcoll where Age > 20 ;
- Query Age >=20 data
db.yourcoll.find ({age: {$gte: 20
Equivalent to MySQL
* from yourcoll where Age >= 20 ;
- Query Age >=20 and age < 30 data
db.yourcoll.find ({age: {$gte: 20 , $lt: }})
Equivalent to MySQL
select * from yourcoll where Age >= 20 and age < 30 ;
- query for data in mail that contains ABC
db.yourcoll.find ({mail: / Abc/i
Equivalent to MySQL
select * from yourcoll like " Span style= "color: #808080;" >% abc% ";
- query username for data that begins with name
db.yourcoll.find ({mail: /^ abc/ i})
Equivalent to MySQL
select * from yourcoll like " Span style= "color: #808080;" >%^ abc% ";
- query username =name1,mail [email protected] Data
db.yourcoll.find ({ Username: "Name1", Mail: "name1 @abc .com "})
Equivalent to MySQL
select from yourcoll where username Span style= "color: #808080;" >= "name1" and mail = "Name1 @abc . com ";
- Querying data for the specified column username and mail
Db.youColl.find ({ },{ username:true, 1})
Equivalent to MySQL
Select from Yourcoll;
Where true can be replaced by 1.
- By username ascending, mail descending order
Db.yourColl.find ({}). Sort ({username:1, mail:-1})
Equivalent to MySQL
Select * from Order by ASC DESC;
- Query 1-2 Data
db.yourColl.find ({}). Limit (2 ). Skip (1 )
Equivalent to MySQL
select * from yourcoll limit Span style= "color: #800000; Font-weight:bold; " >1 , 1
-
Query username = name1 or username =name2 data
db.yourcoll.find ({$
or :
[
{username: "Name1"}, {username: " Name2 "}
})
Equivalent to MySQL
select * from yourcoll = " Name1 "or username = " name2 ";
- Query the number of records that match the criteria
Db.collect1.find ({}). Count ()
Equivalent to MySQL
Select Count (* from Yourcoll
- Db.collection.findOne ()
- Db.collection.findAndModify ()
Three, U
- Db.collection.update ()
- Update username = Name2 User has an age of $
db.yourcoll. set 30 False,
True)
equals MySQL
update yourcoll = 30 where username = "name2";
- Update username = Name2 User's age is age +
db.yourcoll. Update set 30 False,
True)
equals MySQL
update yourcoll = Age Span style= "color: #808080;" >+ 30 where Username = "name2";
- Update username = Name2 User's username = Name3 Age is age + 30
Db.yourcoll. Update ( { username: "Name2" }, { $set: { $ }, $inc: { username: "Name3" } }, False, True)
Equivalent to MySQL
Update Set = + - = where = "Name2";
IV, D
Wu, Rud
- Db.collection.findAndModify () & Db.collection.runCommond ()
db.users.findandmodify ({query: {age: {$gte: 25 - 1 update : {$set : {name: " a2 ' }, $inc: {age: 2 }} , remove:true});
Db.runcommand ({ findandmodify: "Users", 1}, Update: {$set'a2'2}},
Parametersdetailed default ValuesQueryQuery filter condition {} Sortif multiple documents conform to the query filter criteria, the first-ranked object is selected in the arrangement specified by the parameter, and the object is manipulated {} RemoveIf True, the selected object will be deleted before returning n /AUpdatea Modifier object n /aNewIf True, the modified object is returned instead of the original object. In the delete operation, the parameter is ignored. false
External resource Links:
MongoDB CRUD Introduction
Basics of MongoDB Entry DML