MongoDB—SQL到MongoDB映射图表

2024-01-07 17:13:17

一、术语和概念

下表显示了各种 SQL 术语和概念 以及相应的 MongoDB 术语和概念。

SQL Terms/Concepts

MongoDB Terms/Concepts

database

database

table

collection

row

document or BSON document

column

field

index

index

table joins

$lookup, embedded documents

primary key

Specify any unique column or column combination as primary key.

primary key

In MongoDB, the primary key is automatically set to the _id field.

aggregation (e.g. group by)

aggregation pipeline

See the SQL to Aggregation Mapping Chart.

SELECT INTO NEW_TABLE

$out

See the SQL to Aggregation Mapping Chart.

MERGE INTO TABLE

$merge (Available starting in MongoDB 4.2)

See the SQL to Aggregation Mapping Chart.

UNION ALL

$unionWith (Available starting in MongoDB 4.4)

transactions

transactions

二、可执行程序

下表显示了一些数据库可执行文件和相应的MongoDB可执行文件。本表并非详尽无遗。

三、示例

下表显示了各种SQL语句和相应的MongoDB语句。表中的示例假设以下条件：

  • SQL示例假设一个名为people的表。
  • MongoDB示例假设一个名为people的集合包含以下原型的文档：?
{
  _id: ObjectId("509a8fb2f3f4948bd2f983a0"),
  user_id: "abc123",
  age: 55,
  status: 'A'
}

?1、Create and Alter

下表显示了与表级操作相关的各种SQL语句以及相应的MongoDB语句。

SQL Schema Statements

MongoDB Schema Statements

CREATE TABLE people (
id MEDIUMINT NOT NULL
AUTO_INCREMENT,
user_id Varchar(30),
age Number,
status char(1),
PRIMARY KEY (id)
)

?
在第一个insertOne（）或insertMany（）操作上隐式创建。如果未指定_id字段，则自动添加主键_id。
?

db.people.insertOne( {
user_id: "abc123",
age: 55,
status: "A"
} )

然而，您也可以显式创建集合：

db.createCollection("people")
 
    
ALTER TABLE people
ADD join_date DATETIME
 
?托收不描述或强制执行其文件的结构；即，在收集级别没有结构变化。
 然而，在文档级别，updateMany（）操作可以使用$set操作符将字段添加到现有文档中。
 
    
db.people.updateMany(
{ },
{ $set: { join_date: new Date() } }
)
 
    
ALTER TABLE people
DROP COLUMN join_date
 
?托收不描述或强制执行其文件的结构；即，在收集级别没有结构变化。
 然而，在文档级别，updateMany（）操作可以使用$unset操作符从文档中删除字段。?
 
    
db.people.updateMany(
{ },
{ $unset: { "join_date": "" } }
)
 
    
CREATE INDEX idx_user_id_asc
ON people(user_id)
 
    
db.people.createIndex( { user_id: 1 } )
 
    
CREATE INDEX
idx_user_id_asc_age_desc
ON people(user_id, age DESC)
 
    
db.people.createIndex( { user_id: 1, age: -1 } )
 
    
DROP TABLE people
 
    
db.people.drop()
 

?2、Insert
 

下表显示了与将记录插入表中相关的各种SQL语句以及相应的MongoDB语句。
 

 
SQL INSERT Statements
 		 
MongoDB insertOne() Statements
 
 
    
INSERT INTO people(user_id,
age,
status)
VALUES ("bcd001",
45,
"A")
 
    
db.people.insertOne(
{ user_id: "bcd001", age: 45, status: "A" }
)
 

3、select
 

?下表显示了与从表中读取记录相关的各种SQL语句以及相应的MongoDB语句。
 

 
SQL SELECT Statements
 		 
MongoDB find() Statements
 
 
    
SELECT *
FROM people
 
    
db.people.find()
 
    
SELECT id,
user_id,
status
FROM people
 
    
db.people.find(
{ },
{ user_id: 1, status: 1 }
)
 
    
SELECT user_id, status
FROM people
 
    
db.people.find(
{ },
{ user_id: 1, status: 1, _id: 0 }
)
 
    
SELECT *
FROM people
WHERE status = "A"
 
    
db.people.find(
{ status: "A" }
)
 
    
SELECT user_id, status
FROM people
WHERE status = "A"
 
    
db.people.find(
{ status: "A" },
{ user_id: 1, status: 1, _id: 0 }
)
 
    
SELECT *
FROM people
WHERE status != "A"
 
    
db.people.find(
{ status: { $ne: "A" } }
)
 
    
SELECT *
FROM people
WHERE status = "A"
AND age = 50
 
    
db.people.find(
{ status: "A",
age: 50 }
)
 
    
SELECT *
FROM people
WHERE status = "A"
OR age = 50
 
    
db.people.find(
{ $or: [ { status: "A" } , { age: 50 } ] }
)
 
    
SELECT *
FROM people
WHERE age > 25
 
    
db.people.find(
{ age: { $gt: 25 } }
)
 
    
SELECT *
FROM people
WHERE age < 25
 
    
db.people.find(
{ age: { $lt: 25 } }
)
 
    
SELECT *
FROM people
WHERE age > 25
AND age <= 50
 
    
db.people.find(
{ age: { $gt: 25, $lte: 50 } }
)
 
    
SELECT *
FROM people
WHERE user_id like "%bc%"
 
    
db.people.find( { user_id: /bc/ } )
-or-
 
    
db.people.find( { user_id: { $regex: /bc/ } } )
 
    
SELECT *
FROM people
WHERE user_id like "bc%"
 
    
db.people.find( { user_id: /^bc/ } )
-or-
 
    
db.people.find( { user_id: { $regex: /^bc/ } } )
 
    
SELECT *
FROM people
WHERE status = "A"
ORDER BY user_id ASC
 
    
db.people.find( { status: "A" } ).sort( { user_id: 1 } )
 
    
SELECT *
FROM people
WHERE status = "A"
ORDER BY user_id DESC
 
    
db.people.find( { status: "A" } ).sort( { user_id: -1 } )
 
    
SELECT COUNT(*)
FROM people
 
    
db.people.count()
or
 
    
db.people.find().count()
 
    
SELECT COUNT(user_id)
FROM people
 
    
db.people.count( { user_id: { $exists: true } } )
or
 
    
db.people.find( { user_id: { $exists: true } } ).count()
 
    
SELECT COUNT(*)
FROM people
WHERE age > 30
 
    
db.people.count( { age: { $gt: 30 } } )
or
 
    
db.people.find( { age: { $gt: 30 } } ).count()
 
    
SELECT DISTINCT(status)
FROM people
 
    
db.people.aggregate( [ { $group : { _id : "$status" } } ] )
?或者，对于不超过BSON大小限制的不同值集
 
    
db.people.distinct( "status" )
 
    
SELECT *
FROM people
LIMIT 1
 
    
db.people.findOne()
or
 
    
db.people.find().limit(1)
 
    
SELECT *
FROM people
LIMIT 5
SKIP 10
 
    
db.people.find().limit(5).skip(10)
 
    
EXPLAIN SELECT *
FROM people
WHERE status = "A"
 
    
db.people.find( { status: "A" } ).explain()
 

4、update
 

下表显示了与更新表中现有记录相关的各种SQL语句以及相应的MongoDB语句。?
 

 
SQL Update Statements
 		 
MongoDB updateMany() Statements
 
 
    
UPDATE people
SET status = "C"
WHERE age > 25
 
    
db.people.updateMany(
{ age: { $gt: 25 } },
{ $set: { status: "C" } }
)
 
    
UPDATE people
SET age = age + 3
WHERE status = "A"
 
    
db.people.updateMany(
{ status: "A" } ,
{ $inc: { age: 3 } }
)
 

5、delete
 

下表显示了与从表中删除记录相关的各种SQL语句以及相应的MongoDB语句。
 

 
SQL Delete Statements
 		 
MongoDB deleteMany() Statements
 
 
    
DELETE FROM people
WHERE status = "D"
 
    
db.people.deleteMany( { status: "D" } )
 
    
DELETE FROM people
 
    
db.people.deleteMany({})
    		

    		

    			文章来源:https://blog.csdn.net/leesinbad/article/details/135381920

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