Python3-sqlalchemy-orm 多对多关系建表、插入数据、查询数据

现在来设计一个能描述“图书”与“作者”的关系的表结构，需求是

一本书可以有好几个作者一起出版
一个作者可以写好几本书

此时你会发现，用之前学的外键好像没办法实现上面的需求了，因为

当然你更不可以像下面这样干，因为这样就你就相当于有多条书的记录了，太low b了，改书名还得都改。。。

那怎么办呢？此时，我们可以再搞出一张中间表，就可以了

这样就相当于通过book_m2m_author表完成了book表和author表之前的多对多关联

#-*-coding:utf-8-*-
#__author__ = "logan.xu"

import sqlalchemy
from sqlalchemy import create_engine,func
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker,relationship
from sqlalchemy import Table, Column, Integer,String,DATE, ForeignKey
from sqlalchemy.orm import relationship



engine=create_engine("mysql+pymysql://root:12345678@localhost/news",encoding='utf-8',echo=True)
Base=declarative_base()

#一本书可以有多个作者，一个作者又可以出版多本书

book_m2m_author = Table('book_m2m_author', Base.metadata,
                        Column('book_id',Integer,ForeignKey('books.id')),
                        Column('author_id',Integer,ForeignKey('authors.id')),
                        )

class Book(Base):
    __tablename__ = 'books'
    id = Column(Integer,primary_key=True)
    name = Column(String(64))
    pub_date = Column(DATE)

    authors = relationship('Author',secondary=book_m2m_author,backref='books')

    def __repr__(self):
        return self.name

class Author(Base):
    __tablename__ = 'authors'
    id = Column(Integer, primary_key=True)
    name = Column(String(32))

    def __repr__(self):
        return self.name

Base.metadata.create_all(engine)

#-*-coding:utf-8-*-
#__author__ = "logan.xu"

from orm_m2m import orm_m2m
from sqlalchemy.orm import sessionmaker

Session_class=sessionmaker(bind=orm_many_fk.engine) #创建与数据库的链接
session= Session_class() #生成session实例 #cursor

扫描二维码关注公众号，回复： 4832558 查看本文章

/Users/drizzle/PycharmProjects/2018-12-03/venv/bin/python /Users/drizzle/PycharmProjects/2018-12-03/orm_m2m/orm_m2m.py
2019-01-08 19:35:48,687 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'sql_mode'
2019-01-08 19:35:48,687 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,689 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'lower_case_table_names'
2019-01-08 19:35:48,689 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,691 INFO sqlalchemy.engine.base.Engine SELECT DATABASE()
2019-01-08 19:35:48,691 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,692 INFO sqlalchemy.engine.base.Engine show collation where `Charset` = 'utf8mb4' and `Collation` = 'utf8mb4_bin'
2019-01-08 19:35:48,692 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,694 INFO sqlalchemy.engine.base.Engine SELECT CAST('test plain returns' AS CHAR(60)) AS anon_1
2019-01-08 19:35:48,695 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,695 INFO sqlalchemy.engine.base.Engine SELECT CAST('test unicode returns' AS CHAR(60)) AS anon_1
2019-01-08 19:35:48,695 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,696 INFO sqlalchemy.engine.base.Engine SELECT CAST('test collated returns' AS CHAR CHARACTER SET utf8mb4) 
COLLATE utf8mb4_bin AS anon_1
2019-01-08 19:35:48,696 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,697 INFO sqlalchemy.engine.base.Engine DESCRIBE `book_m2m_author`
2019-01-08 19:35:48,697 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,698 INFO sqlalchemy.engine.base.Engine ROLLBACK
2019-01-08 19:35:48,698 INFO sqlalchemy.engine.base.Engine DESCRIBE `books`
2019-01-08 19:35:48,698 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,699 INFO sqlalchemy.engine.base.Engine ROLLBACK
2019-01-08 19:35:48,699 INFO sqlalchemy.engine.base.Engine DESCRIBE `authors`
2019-01-08 19:35:48,699 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,699 INFO sqlalchemy.engine.base.Engine ROLLBACK
2019-01-08 19:35:48,700 INFO sqlalchemy.engine.base.Engine 
CREATE TABLE books (
    id INTEGER NOT NULL AUTO_INCREMENT, 
    name VARCHAR(64), 
    pub_date DATE, 
    PRIMARY KEY (id)
)


2019-01-08 19:35:48,700 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,793 INFO sqlalchemy.engine.base.Engine COMMIT
2019-01-08 19:35:48,794 INFO sqlalchemy.engine.base.Engine 
CREATE TABLE authors (
    id INTEGER NOT NULL AUTO_INCREMENT, 
    name VARCHAR(32), 
    PRIMARY KEY (id)
)


2019-01-08 19:35:48,794 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,800 INFO sqlalchemy.engine.base.Engine COMMIT
2019-01-08 19:35:48,802 INFO sqlalchemy.engine.base.Engine 
CREATE TABLE book_m2m_author (
    book_id INTEGER, 
    author_id INTEGER, 
    FOREIGN KEY(book_id) REFERENCES books (id), 
    FOREIGN KEY(author_id) REFERENCES authors (id)
)


2019-01-08 19:35:48,802 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:35:48,811 INFO sqlalchemy.engine.base.Engine COMMIT

Process finished with exit code 0

mysql> show tables;
+-----------------+
| Tables_in_news  |
+-----------------+
| address         |
| authors         |
| book_m2m_author |
| books           |
| customer        |
| student         |
| study_record    |
| user            |
+-----------------+
8 rows in set (0.00 sec)

mysql> show create table authors;
+---------+--------------------------------------------------------------+
| Table   | Create Table                                                                                                                                                                                |
+---------+--------------------------------------------------------------+
| authors | CREATE TABLE `authors` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(32) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci |
+---------+-------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> show create table book_m2m_author;
+-----------------+--------------------------------------------------------------------------+
| Table           | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                 |
+-----------------+--------------------------------------------------------------------------+
| book_m2m_author | CREATE TABLE `book_m2m_author` (
  `book_id` int(11) DEFAULT NULL,
  `author_id` int(11) DEFAULT NULL,
  KEY `book_id` (`book_id`),
  KEY `author_id` (`author_id`),
  CONSTRAINT `book_m2m_author_ibfk_1` FOREIGN KEY (`book_id`) REFERENCES `books` (`id`),
  CONSTRAINT `book_m2m_author_ibfk_2` FOREIGN KEY (`author_id`) REFERENCES `authors` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci |
+-----------------+-------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> show create table books;
+-------+-------------------------------------------------------------+
| Table | Create Table                                                                                                                                                                                                              |
+-------+-------------------------------------------------------------+
| books | CREATE TABLE `books` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(64) DEFAULT NULL,
  `pub_date` date DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci |
+---------------------------------------------------------------------+

mysql> desc book_m2m_author;
+-----------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+-------+
| book_id | int(11) | YES | MUL | NULL | |
| author_id | int(11) | YES | MUL | NULL | |
+-----------+---------+------+-----+---------+-------+
2 rows in set (0.00 sec)

#-*-coding:utf-8-*-
#__author__ = "logan.xu"

from m2m import orm_m2m
from sqlalchemy.orm import sessionmaker

Session_class=sessionmaker(bind=orm_m2m.engine) #创建与数据库的链接
session= Session_class() #生成session实例 #cursor

#插入数据

b1= orm_m2m.Book(name="learn python with Alex", pub_date="2019-01-08")
b2= orm_m2m.Book(name="learn JAVA with Alex", pub_date="2019-01-09")
b3= orm_m2m.Book(name="learn LINUX with Alex", pub_date="2019-01-10")

a1= orm_m2m.Author(name="Alex")
a2= orm_m2m.Author(name="Jack")
a3= orm_m2m.Author(name="Eric")

b1.authors=[a1,a3]
b3.authors=[a1,a2,a3]

session.add_all([b1,b2,b3,a1,a2,a3])

session.commit()

/Users/drizzle/PycharmProjects/2018-12-03/venv/bin/python /Users/drizzle/PycharmProjects/2018-12-03/m2m/orm_m2m_api.py
2019-01-08 19:54:48,757 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'sql_mode'
2019-01-08 19:54:48,757 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,759 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'lower_case_table_names'
2019-01-08 19:54:48,759 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,760 INFO sqlalchemy.engine.base.Engine SELECT DATABASE()
2019-01-08 19:54:48,761 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,761 INFO sqlalchemy.engine.base.Engine show collation where `Charset` = 'utf8mb4' and `Collation` = 'utf8mb4_bin'
2019-01-08 19:54:48,761 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,764 INFO sqlalchemy.engine.base.Engine SELECT CAST('test plain returns' AS CHAR(60)) AS anon_1
2019-01-08 19:54:48,764 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,765 INFO sqlalchemy.engine.base.Engine SELECT CAST('test unicode returns' AS CHAR(60)) AS anon_1
2019-01-08 19:54:48,765 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,765 INFO sqlalchemy.engine.base.Engine SELECT CAST('test collated returns' AS CHAR CHARACTER SET utf8mb4) 
COLLATE utf8mb4_bin AS anon_1
2019-01-08 19:54:48,765 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,767 INFO sqlalchemy.engine.base.Engine DESCRIBE `book_m2m_author`
2019-01-08 19:54:48,767 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,768 INFO sqlalchemy.engine.base.Engine DESCRIBE `books`
2019-01-08 19:54:48,768 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,769 INFO sqlalchemy.engine.base.Engine DESCRIBE `authors`
2019-01-08 19:54:48,769 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:54:48,777 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
2019-01-08 19:54:48,777 INFO sqlalchemy.engine.base.Engine INSERT INTO authors (name) VALUES (%(name)s)
2019-01-08 19:54:48,777 INFO sqlalchemy.engine.base.Engine {'name': 'Alex'}
2019-01-08 19:54:48,778 INFO sqlalchemy.engine.base.Engine INSERT INTO authors (name) VALUES (%(name)s)
2019-01-08 19:54:48,778 INFO sqlalchemy.engine.base.Engine {'name': 'Jack'}
2019-01-08 19:54:48,779 INFO sqlalchemy.engine.base.Engine INSERT INTO authors (name) VALUES (%(name)s)
2019-01-08 19:54:48,779 INFO sqlalchemy.engine.base.Engine {'name': 'Eric'}
2019-01-08 19:54:48,780 INFO sqlalchemy.engine.base.Engine INSERT INTO books (name, pub_date) VALUES (%(name)s, %(pub_date)s)
2019-01-08 19:54:48,780 INFO sqlalchemy.engine.base.Engine {'name': 'learn python with Alex', 'pub_date': '2019-01-08'}
2019-01-08 19:54:48,780 INFO sqlalchemy.engine.base.Engine INSERT INTO books (name, pub_date) VALUES (%(name)s, %(pub_date)s)
2019-01-08 19:54:48,781 INFO sqlalchemy.engine.base.Engine {'name': 'learn LINUX with Alex', 'pub_date': '2019-01-10'}
2019-01-08 19:54:48,781 INFO sqlalchemy.engine.base.Engine INSERT INTO books (name, pub_date) VALUES (%(name)s, %(pub_date)s)
2019-01-08 19:54:48,781 INFO sqlalchemy.engine.base.Engine {'name': 'learn JAVA with Alex', 'pub_date': '2019-01-09'}
2019-01-08 19:54:48,782 INFO sqlalchemy.engine.base.Engine INSERT INTO book_m2m_author (book_id, author_id) VALUES (%(book_id)s, %(author_id)s)
2019-01-08 19:54:48,782 INFO sqlalchemy.engine.base.Engine ({'book_id': 2, 'author_id': 1}, {'book_id': 2, 'author_id': 2}, 
{'book_id': 2, 'author_id': 3}, {'book_id': 1, 'author_id': 1}, {'book_id': 1, 'author_id': 3})
2019-01-08 19:54:48,783 INFO sqlalchemy.engine.base.Engine COMMIT

Process finished with exit code 0

mysql> select * from authors;
+----+------+
| id | name |
+----+------+
|  1 | Alex |
|  2 | Jack |
|  3 | Eric |
+----+------+
3 rows in set (0.00 sec)

mysql> select * from book_m2m_author;
+---------+-----------+
| book_id | author_id |
+---------+-----------+
|       2 |         1 |
|       2 |         2 |
|       2 |         3 |
|       1 |         1 |
|       1 |         3 |
+---------+-----------+
5 rows in set (0.00 sec)

mysql> select * from books;
+----+------------------------+------------+
| id | name                   | pub_date   |
+----+------------------------+------------+
|  1 | learn python with Alex | 2019-01-08 |
|  2 | learn LINUX with Alex  | 2019-01-10 |
|  3 | learn JAVA with Alex   | 2019-01-09 |
+----+------------------------+------------+
3 rows in set (0.00 sec)

#查询
#-*-coding:utf-8-*-
#__author__ = "logan.xu"

from m2m import orm_m2m
from sqlalchemy.orm import sessionmaker

Session_class=sessionmaker(bind=orm_m2m.engine) #创建与数据库的链接
session= Session_class() #生成session实例 #cursor

#插入数据

#b1= orm_m2m.Book(name="learn python with Alex", pub_date="2019-01-08")#
#b2= orm_m2m.Book(name="learn JAVA with Alex", pub_date="2019-01-09")
#b3= orm_m2m.Book(name="learn LINUX with Alex", pub_date="2019-01-10")
#
#a1= orm_m2m.Author(name="Alex")
#a2= orm_m2m.Author(name="Jack")
#a3= orm_m2m.Author(name="Eric")
#
#b1.authors=[a1,a3]
#b3.authors=[a1,a2,a3]
#
#session.add_all([b1,b2,b3,a1,a2,a3])

#查询数据
author_obj=session.query(orm_m2m.Author).filter(orm_m2m.Author.name=="alex").first()
print(author_obj.books)

session.commit()

/Users/drizzle/PycharmProjects/2018-12-03/venv/bin/python /Users/drizzle/PycharmProjects/2018-12-03/m2m/orm_m2m_api.py
2019-01-08 19:59:34,860 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'sql_mode'
2019-01-08 19:59:34,860 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,862 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'lower_case_table_names'
2019-01-08 19:59:34,862 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,864 INFO sqlalchemy.engine.base.Engine SELECT DATABASE()
2019-01-08 19:59:34,864 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,865 INFO sqlalchemy.engine.base.Engine show collation where `Charset` = 'utf8mb4' and `Collation` = 'utf8mb4_bin'
2019-01-08 19:59:34,865 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,868 INFO sqlalchemy.engine.base.Engine SELECT CAST('test plain returns' AS CHAR(60)) AS anon_1
2019-01-08 19:59:34,868 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,869 INFO sqlalchemy.engine.base.Engine SELECT CAST('test unicode returns' AS CHAR(60)) AS anon_1
2019-01-08 19:59:34,869 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,870 INFO sqlalchemy.engine.base.Engine SELECT CAST('test collated returns' AS CHAR CHARACTER SET utf8mb4) 
COLLATE utf8mb4_bin AS anon_1
2019-01-08 19:59:34,870 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,871 INFO sqlalchemy.engine.base.Engine DESCRIBE `book_m2m_author`
2019-01-08 19:59:34,871 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,872 INFO sqlalchemy.engine.base.Engine DESCRIBE `books`
2019-01-08 19:59:34,872 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,873 INFO sqlalchemy.engine.base.Engine DESCRIBE `authors`
2019-01-08 19:59:34,873 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 19:59:34,879 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
2019-01-08 19:59:34,880 INFO sqlalchemy.engine.base.Engine SELECT authors.id AS authors_id, authors.name AS authors_name 
FROM authors 
WHERE authors.name = %(name_1)s 
 LIMIT %(param_1)s
2019-01-08 19:59:34,880 INFO sqlalchemy.engine.base.Engine {'name_1': 'alex', 'param_1': 1}
2019-01-08 19:59:34,882 INFO sqlalchemy.engine.base.Engine SELECT books.id AS books_id, books.name AS books_name,
 books.pub_date AS books_pub_date 
FROM books, book_m2m_author 
WHERE %(param_1)s = book_m2m_author.author_id AND books.id = book_m2m_author.book_id
2019-01-08 19:59:34,882 INFO sqlalchemy.engine.base.Engine {'param_1': 1}
[learn LINUX with Alex, learn python with Alex]
2019-01-08 19:59:34,883 INFO sqlalchemy.engine.base.Engine COMMIT

Process finished with exit code 0

#-*-coding:utf-8-*-
#__author__ = "logan.xu"

from m2m import orm_m2m
from sqlalchemy.orm import sessionmaker

Session_class=sessionmaker(bind=orm_m2m.engine) #创建与数据库的链接
session= Session_class() #生成session实例 #cursor

#插入数据

#b1= orm_m2m.Book(name="learn python with Alex", pub_date="2019-01-08")#
#b2= orm_m2m.Book(name="learn JAVA with Alex", pub_date="2019-01-09")
#b3= orm_m2m.Book(name="learn LINUX with Alex", pub_date="2019-01-10")
#
#a1= orm_m2m.Author(name="Alex")
#a2= orm_m2m.Author(name="Jack")
#a3= orm_m2m.Author(name="Eric")
#
#b1.authors=[a1,a3]
#b3.authors=[a1,a2,a3]
#
#session.add_all([b1,b2,b3,a1,a2,a3])

#查询数据
author_obj=session.query(orm_m2m.Author).filter(orm_m2m.Author.name=="alex").first()
print(author_obj.books)

book_obj=session.query(orm_m2m.Book).filter(orm_m2m.Book.id==2).first()
print(book_obj)

session.commit()

/Users/drizzle/PycharmProjects/2018-12-03/venv/bin/python /Users/drizzle/PycharmProjects/2018-12-03/m2m/orm_m2m_api.py
2019-01-08 20:03:36,934 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'sql_mode'
2019-01-08 20:03:36,934 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,936 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'lower_case_table_names'
2019-01-08 20:03:36,936 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,937 INFO sqlalchemy.engine.base.Engine SELECT DATABASE()
2019-01-08 20:03:36,937 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,938 INFO sqlalchemy.engine.base.Engine show collation where `Charset` = 'utf8mb4' and `Collation` = 'utf8mb4_bin'
2019-01-08 20:03:36,938 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,941 INFO sqlalchemy.engine.base.Engine SELECT CAST('test plain returns' AS CHAR(60)) AS anon_1
2019-01-08 20:03:36,941 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,942 INFO sqlalchemy.engine.base.Engine SELECT CAST('test unicode returns' AS CHAR(60)) AS anon_1
2019-01-08 20:03:36,942 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,942 INFO sqlalchemy.engine.base.Engine SELECT CAST('test collated returns' AS CHAR CHARACTER SET utf8mb4) 
COLLATE utf8mb4_bin AS anon_1
2019-01-08 20:03:36,942 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,943 INFO sqlalchemy.engine.base.Engine DESCRIBE `book_m2m_author`
2019-01-08 20:03:36,943 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,945 INFO sqlalchemy.engine.base.Engine DESCRIBE `books`
2019-01-08 20:03:36,945 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,946 INFO sqlalchemy.engine.base.Engine DESCRIBE `authors`
2019-01-08 20:03:36,946 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:03:36,953 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
2019-01-08 20:03:36,953 INFO sqlalchemy.engine.base.Engine SELECT authors.id AS authors_id, authors.name AS authors_name 
FROM authors 
WHERE authors.name = %(name_1)s 
 LIMIT %(param_1)s
2019-01-08 20:03:36,953 INFO sqlalchemy.engine.base.Engine {'name_1': 'alex', 'param_1': 1}
2019-01-08 20:03:36,955 INFO sqlalchemy.engine.base.Engine SELECT books.id AS books_id, books.name AS books_name, 
books.pub_date AS books_pub_date 
FROM books, book_m2m_author 
WHERE %(param_1)s = book_m2m_author.author_id AND books.id = book_m2m_author.book_id
2019-01-08 20:03:36,955 INFO sqlalchemy.engine.base.Engine {'param_1': 1}
[learn LINUX with Alex, learn python with Alex]
2019-01-08 20:03:36,957 INFO sqlalchemy.engine.base.Engine SELECT books.id AS books_id, books.name AS books_name, 
books.pub_date AS books_pub_date 
FROM books 
WHERE books.id = %(id_1)s 
 LIMIT %(param_1)s
2019-01-08 20:03:36,957 INFO sqlalchemy.engine.base.Engine {'id_1': 2, 'param_1': 1}
learn LINUX with Alex
2019-01-08 20:03:36,958 INFO sqlalchemy.engine.base.Engine COMMIT

Process finished with exit code 0

#-*-coding:utf-8-*-
#__author__ = "logan.xu"

from m2m import orm_m2m
from sqlalchemy.orm import sessionmaker

Session_class=sessionmaker(bind=orm_m2m.engine) #创建与数据库的链接
session= Session_class() #生成session实例 #cursor

#插入数据

#b1= orm_m2m.Book(name="learn python with Alex", pub_date="2019-01-08")#
#b2= orm_m2m.Book(name="learn JAVA with Alex", pub_date="2019-01-09")
#b3= orm_m2m.Book(name="learn LINUX with Alex", pub_date="2019-01-10")
#
#a1= orm_m2m.Author(name="Alex")
#a2= orm_m2m.Author(name="Jack")
#a3= orm_m2m.Author(name="Eric")
#
#b1.authors=[a1,a3]
#b3.authors=[a1,a2,a3]
#
#session.add_all([b1,b2,b3,a1,a2,a3])

#查询数据
author_obj=session.query(orm_m2m.Author).filter(orm_m2m.Author.name=="alex").first()
print(author_obj.books)

book_obj=session.query(orm_m2m.Book).filter(orm_m2m.Book.id==2).first()
print(book_obj.authors)

session.commit()

/Users/drizzle/PycharmProjects/2018-12-03/venv/bin/python /Users/drizzle/PycharmProjects/2018-12-03/m2m/orm_m2m_api.py
2019-01-08 20:04:49,122 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'sql_mode'
2019-01-08 20:04:49,122 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,124 INFO sqlalchemy.engine.base.Engine SHOW VARIABLES LIKE 'lower_case_table_names'
2019-01-08 20:04:49,124 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,126 INFO sqlalchemy.engine.base.Engine SELECT DATABASE()
2019-01-08 20:04:49,126 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,127 INFO sqlalchemy.engine.base.Engine show collation where `Charset` = 'utf8mb4' and `Collation` = 'utf8mb4_bin'
2019-01-08 20:04:49,127 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,130 INFO sqlalchemy.engine.base.Engine SELECT CAST('test plain returns' AS CHAR(60)) AS anon_1
2019-01-08 20:04:49,130 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,131 INFO sqlalchemy.engine.base.Engine SELECT CAST('test unicode returns' AS CHAR(60)) AS anon_1
2019-01-08 20:04:49,131 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,131 INFO sqlalchemy.engine.base.Engine SELECT CAST('test collated returns' AS CHAR CHARACTER SET utf8mb4) 
COLLATE utf8mb4_bin AS anon_1
2019-01-08 20:04:49,131 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,132 INFO sqlalchemy.engine.base.Engine DESCRIBE `book_m2m_author`
2019-01-08 20:04:49,132 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,133 INFO sqlalchemy.engine.base.Engine DESCRIBE `books`
2019-01-08 20:04:49,133 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,135 INFO sqlalchemy.engine.base.Engine DESCRIBE `authors`
2019-01-08 20:04:49,135 INFO sqlalchemy.engine.base.Engine {}
2019-01-08 20:04:49,141 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
2019-01-08 20:04:49,141 INFO sqlalchemy.engine.base.Engine SELECT authors.id AS authors_id, authors.name AS authors_name 
FROM authors 
WHERE authors.name = %(name_1)s 
 LIMIT %(param_1)s
2019-01-08 20:04:49,141 INFO sqlalchemy.engine.base.Engine {'name_1': 'alex', 'param_1': 1}
2019-01-08 20:04:49,143 INFO sqlalchemy.engine.base.Engine SELECT books.id AS books_id, books.name AS books_name, 
books.pub_date AS books_pub_date 
FROM books, book_m2m_author 
WHERE %(param_1)s = book_m2m_author.author_id AND books.id = book_m2m_author.book_id
2019-01-08 20:04:49,143 INFO sqlalchemy.engine.base.Engine {'param_1': 1}
[learn LINUX with Alex, learn python with Alex]
2019-01-08 20:04:49,145 INFO sqlalchemy.engine.base.Engine SELECT books.id AS books_id, books.name AS books_name, 
books.pub_date AS books_pub_date 
FROM books 
WHERE books.id = %(id_1)s 
 LIMIT %(param_1)s
2019-01-08 20:04:49,145 INFO sqlalchemy.engine.base.Engine {'id_1': 2, 'param_1': 1}
2019-01-08 20:04:49,146 INFO sqlalchemy.engine.base.Engine SELECT authors.id AS authors_id, authors.name AS authors_name 
FROM authors, book_m2m_author 
WHERE %(param_1)s = book_m2m_author.book_id AND authors.id = book_m2m_author.author_id
2019-01-08 20:04:49,146 INFO sqlalchemy.engine.base.Engine {'param_1': 2}
[Alex, Jack, Eric]
2019-01-08 20:04:49,147 INFO sqlalchemy.engine.base.Engine COMMIT

Process finished with exit code 0

Python3-sqlalchemy-orm 多对多关系建表、插入数据、查询数据

猜你喜欢