SQL到MongoDB的映射图表

在本页面

除了下面的图表之外,您可能需要考虑有关MongoDB的常见问题的常见问题部分。

术语和概念

下表介绍了各种SQL术语和概念以及相应的MongoDB术语和概念。

SQL术语/概念
MongoDB术语/概念

database

table

row

column

index

table joins

primary key (指定任何唯一的列或列组合作为主键。)

aggregation (e.g. group by)

SELECT INTO NEW_TABLE

MERGE INTO TABLE

Transactions

可执行文件

下表展示了一些数据库可执行文件和相应的MongoDB可执行文件。这个表格并不是详尽无遗的。

MongoDB
MySQL
Oracle
Informix
DB2

Database Server

mysqld

oracle

IDS

DB2 Server

Database Client

mysql

sqlplus

DB-Access

DB2 Client

例子

下表展示了各种SQL语句和相应的MongoDB语句。表中的例子假设以下条件:

  • SQL示例假设有一个名为people的表。

  • MongoDB示例假设一个名为people的集合,它包含以下原型的文档:

 { 
       _id: ObjectId("509a8fb2f3f4948bd2f983a0"),
       user_id: "abc123",
       age: 55,
       status: 'A'
 }

创建和修改

下表展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语句
MongoDB Schema语句

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

ALTER TABLE people ADD join_date DATETIME

ALTER TABLE people DROP COLUMN 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()

有关使用的方法和运算符的更多信息,请参见:

另看:

插入

下表显示了与将记录插入表和相应的MongoDB语句有关的各种SQL语句。

SQL INSERT语句

MongoDB insertOne() Statements

INSERT INTO people(user_id, age, status) VALUES ("bcd001", 45, "A")

db.people.insertOne( { user_id: "bcd001", age: 45, status: "A" } )

有关更多信息,请参见db.collection.insertOne()

也可以看看:

选择

下表展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。

注意

除非通过投影明确排除,否则[find()方法始终在返回的文档中包含**_id字段。 下面的某些SQL查询可能包含一个_id**字段来反映这一点,即使该字段未包含在相应的find()查询中也是如此。

SQL SELECT 语句
MongoDB find() 语句

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

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()

有关使用的方法和运算符的更多信息,请参见:

另看:

更新记录

下表显示了与更新表中的现有记录和相应的MongoDB语句有关的各种SQL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 } } )

有关示例中使用的方法和运算符的更多信息,请参见:

另看:

删除记录

下表显示了与从表中删除记录和相应的MongoDB语句有关的各种SQL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({})

获得更多信息,请参见:db.collection.deleteMany().

另看:

进一步阅读

如果您正在考虑将SQL应用程序迁移到MongoDB,请下载《 MongoDB应用程序现代化指南》

下载内容包括以下资源:

  • 演示使用MongoDB进行数据建模的方法

  • 白皮书涵盖了从RDBMS数据模型迁移到MongoDB的最佳实践和注意事项

  • 参考MongoDB模式及其等效RDBMS

  • 应用程序现代化记分卡

译者:杨帅

校对:杨帅

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