MongoDB学习第七篇 --- sql和mongodb对比

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一、术语和概念的对比

SQLMongoDB
database database
   
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

 

 

 

二、对库和表的操作语句对比

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

 直接执行insert操作即可,如果表不存在,自动创建

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

 也可以用一下语句创建collection

db.createCollection("people")
ALTER TABLE people
ADD join_date DATETIME
db.people.updateMany(
    { },
    { $set: { join_date: new Date() } }
)
ALTER TABLE people
DROP COLUMN join_date
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()

 

三、insert语句的对比

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

 

四、select语句的对比

SQL SELECT StatementsMongoDB 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.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()

 

五、update语句的对比

SQL Update StatementsMongoDB 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 } }
)

 

 

六、delete语句的对比

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

 

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