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

/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、查询数据的更多相关文章

Entity Framework 6 Recipes 2nd Edition（10-9）译 -> 在多对多关系中为插入和删除使用存储过程
10-9. 在多对多关系中为插入和删除使用存储过程问题想要在一个无载荷的多对多关系中使用存储过程(存储过程只影响关系的连接表) 解决方案假设有一个多对多关系的作者( Author)表和书籍( B ...
orm 语法数据库连接、建表、增删改查、回滚、单键关联、多键关联、三表关联
1.数据库连接, #!usr/bin/env/python # -*- coding:utf-8 -*- # from wangteng import sqlalchemy from sqlalche ...
Python sqlalchemy orm 多对多外键关联
多对多外键关联注:使用三张表进行对应关联实现代码: # 创建3个表配置外键关联 # 调用Column创建字段加类型 from sqlalchemy import Table, Column, ...
sqlalchemy操作----建表插入查询删除
... #!_*_coding:utf-8_*_ #__author__:"Alex huang" import sqlalchemy from sqlalchemy import ...
GreenDao关系建表
关系在greenDAO,实体涉及使用一对一或一对多的关系.例如,如果要模拟一个1:greenDAOñ关系,你将有一个一对一和一对多的关系.但是,请注意,一对一和一对多的关系不是相互连接,所以你必须同 ...
mysql 常用命令,连接数据库,查看建表语句,批量导入数据,批量更新数据,连接查询
1. 1)MySQL 连接本地数据库,从cmd中进入mysql命令编辑器: root root分别为用户名和密码 mysql -uroot -proot 2)MySQL 连接本地数据库,用户名为“ro ...
sql server建库建表（数据库和数据表的常用操作）
数据库和数据表 (开发常用操作) 一,数据库的创建一个SQLServer 是由两个文件组成的:数据文件(mdf) 和日志文件(ldf),所以我们创建数据库就是要为其指定数据库名.数据文件和日志文件 ...
mysql 个人博客应用的建表和相关查询
一.建表用户表tb_user create table if not exists tb_user( user_id int auto_increment, ) not null, user_pas ...
50个SQL语句(MySQL版) 建表插入数据
本学期正在学习数据库,前段时间老师让我们做一下50个经典SQL语句,当时做的比较快,有一些也是百度的,自我感觉理解的不是很透彻. 所以从本篇随笔开始,我将进行50个经典SQL语句的复盘,加深理解. 答 ...

随机推荐

【排序+模拟】谁拿了最多奖学金 luogu-1051
题目描述某校的惯例是在每学期的期末考试之后发放奖学金.发放的奖学金共有五种,获取的条件各自不同: 院士奖学金,每人$ 8000 $元,期末平均成绩高于$80$分($>80$),并且在本 ...
fatal error: all goroutines are asleep - deadlock!
一.问题截图 fatal error: all goroutines are asleep - deadlock! goroutine 1 [chan receive]: main.main() /U ...
C++第四十六篇 -- C++将int转换成宽字符串
int rate = 60; int score = 80 TCHAR Temp[64] = TEXT(""); _stprintf_s(Temp, TEXT("pass ...
C++第三十四篇 -- 安装Windows Driver后，编译以前项目出现打不开lib文件
VS2017默认是没有安装WDK的,但是我们写驱动文件的话需要用到WDK.不过安装了WDK后,发现以前一些正常的项目在Release模式下编译会报LINK1104,无法打开.lib的错误针对这个错误 ...
Vue--el-menu 的自动跳转功能与自己的click事件冲突
一\先看elementUI说明项目实际此时点击活导航时以 index 作为 path 进行路由跳转那么此时不要onclik事件了如果此时有在有click 就
SQL Server CPU 利用率毛刺的分析定位与解决
一.背景 1.1 问题描述近期发现一台SQL Server的CPU利用率很不稳定,发现不定时的飙升到100%,更可怕的是在业务繁忙时,影响了业务调用,失败率明显增加,所以,减低CPU的利用率,是迫切 ...
修改Eureka的metadata脚本
最近研究了一下Spring Cloud的灰度发布, 发现方法真是多. 这里先提供一个修改Eureka注册中心里的instance实例的metadata的脚本, 可以方便地用来测试效果. 使用举例: s ...
Git基本理论---重点
Git本地有三个工作区域: 工作目录(Working Directory): 存放项目代码暂存区(Stage/Index) : 临时存放文件的改动,保存的是文件列表信息资源库 (Repositor ...
rot位移密码详解（rot5、rot13、rot18、rot47）
最近训练CTF的时候,发现密码学这块的知识不太系统,所以自己接下来会陆陆续续整理出来 rot密码 rot密码其实可以看作是凯撒密码的一种变式本质都是移位运算 rot密码按种类大致分为以下几类 rot ...
C++ //多态 //静态多态：函数重载和运算符重载属于静态多态，复用函数名 //动态多态：派生类和虚函数实现运行时多态
1 //多态 2 //静态多态:函数重载和运算符重载属于静态多态 ,复用函数名 3 //动态多态:派生类和虚函数实现运行时多态 4 5 //静态多态和动态多态的区别 6 //静态多态的函数地址早 ...

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

Python3-sqlalchemy-orm 多对多关系建表、插入数据、查询数据的更多相关文章

随机推荐

热门专题