一、介绍：

??模型类被创建在"应用目录/models.py"文件中。模型类必须继承自Model类，位于包dango.db.models中。接下来首先以"影片-人物"管理为例进行演示。
1定义在models.py文件中定义模型类。

from django.db import models

# Create your models here.
#影片信息模型类
class FilmInfo(models.Model):
    """fimInfo model"""
    fid = models.AutoField(primary_key=True, verbose_name='影片编号')
    fname = models.CharField(max_length=20, verbose_name="影片名称")
    playcount = models.IntegerField(default=0, verbose_name="播放量")
    commentcount = models.IntegerField(default=8, verbose_name="评论量")
    pub_date = models.DateField(null=True, verbose_name="发布日期")
    is_delete = models.BooleanField(default=False,verbose_name="逻辑删除")

    class Meta:
        db_table = "filminfo" #指明数据库表名
        verbose_name ="影片信息" #在admin站点中显示的名称
#优化模型类输出
    def __str__(self):
         return self.fname

class PeopleInfo(models.Model):
	GENDER_CHOICES=(
		(0,'男'),
		(1,'女')
	)
	uid=models.AutoField(primary_key=True,verbose_name='编号')
	uname=models.CharField(max_length=10,verbose_name='编号')
	gender=models.SmallIntegerField(choices=GENDER_CHOICES,default=0,verbose_name='性别')
	desc =models.CharField(max_length=2000,null=True,verbose_name='简介')
	# 外键约束，人物属于那部影片
	film=models.ForeignKey(FilmInfo,on_delete=models.CASCADE,verbose_name='影片')
	is_delete = models.BooleanField(default=False,verbose_name='逻辑删除')

	class Meta:
		db_table='t_peopleinfo'  #指名数据库表名
		verbose_name='人物信息'  #在admin 站点中显示的名称
	#优化模型类输出
	def __str__(self):
		return self.uname

下面结果会报错，

#创建牵引文件连接数据库，Mysql ,下面连接数据库会报错。
  (py3_001) boot@boot-virtual-machine:~/Desktop/djprojects/film_manager$ python manage.py makemigrations film
Traceback (most recent call last):
  File "/home/boot/Desktop/djprojects/film_manager/manage.py", line 22, in <module>
    main()

  ...........................................................
  File "/home/boot/.virtualenvs/py3_001/lib/python3.9/site-packages/pymysql/_auth.py", line 265, in caching_sha2_password_auth
    data = sha2_rsa_encrypt(conn.password, conn.salt, conn.server_public_key)
  File "/home/boot/.virtualenvs/py3_001/lib/python3.9/site-packages/pymysql/_auth.py", line 143, in sha2_rsa_encrypt
    raise RuntimeError(
RuntimeError: 'cryptography' package is required for sha256_password or caching_sha2_password auth methods

??由上面的错误提示可知，连接数据库时候，cryptography 包是required。解决办法，需要安装：pip install cryptography。即可成功解决.结果如下图所示：

(py3_001) boot@boot-virtual-machine:~/Desktop/djprojects/film_manager$ pip install cryptography
Collecting cryptography
  Downloading cryptography-35.0.0-cp36-abi3-manylinux_2_24_x86_64.whl (3.5 MB)
     |████████████████████████████████| 3.5 MB 1.4 MB/s 
Collecting cffi>=1.12
  Downloading cffi-1.15.0-cp39-cp39-manylinux_2_12_x86_64.manylinux2010_x86_64.whl (444 kB)
     |████████████████████████████████| 444 kB 190 kB/s 
Collecting pycparser
  Downloading pycparser-2.21-py2.py3-none-any.whl (118 kB)
     |████████████████████████████████| 118 kB 611 kB/s 
Installing collected packages: pycparser, cffi, cryptography
Successfully installed cffi-1.15.0 cryptography-35.0.0 pycparser-2.21
(py3_001) boot@boot-virtual-machine:~/Desktop/djprojects/film_manager$ python manage.py makemigrations film
Migrations for 'film':
  film/migrations/0001_initial.py
    - Create model FilmInfo
    - Create model PeopleInfo
(py3_001) boot@boot-virtual-machine:~/Desktop/djprojects/film_manager$

二、根据迁移文件生成映射书库据表。

??所以可以看到我们创建的两个模型类已经运行成功。分别是：Create model FilmInfo，Create model PeopleInfo。接下来我们去生成映射书库据表。

(py3_001) boot@boot-virtual-machine:~/Desktop/djprojects/film_manager$ python manage.py migrate #生成映射书库据表。
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, film, sessions
Running migrations:
  Applying contenttypes.0001_initial... OK
  Applying auth.0001_initial... OK
  Applying admin.0001_initial... OK
  Applying admin.0002_logentry_remove_auto_add... OK
  Applying admin.0003_logentry_add_action_flag_choices... OK
  Applying contenttypes.0002_remove_content_type_name... OK
  Applying auth.0002_alter_permission_name_max_length... OK
  Applying auth.0003_alter_user_email_max_length... OK
  Applying auth.0004_alter_user_username_opts... OK
  Applying auth.0005_alter_user_last_login_null... OK
  Applying auth.0006_require_contenttypes_0002... OK
  Applying auth.0007_alter_validators_add_error_messages... OK
  Applying auth.0008_alter_user_username_max_length... OK
  Applying auth.0009_alter_user_last_name_max_length... OK
  Applying auth.0010_alter_group_name_max_length... OK
  Applying auth.0011_update_proxy_permissions... OK
  Applying auth.0012_alter_user_first_name_max_length... OK
  Applying film.0001_initial... OK
  Applying sessions.0001_initial... OK
(py3_001) boot@boot-virtual-machine:~/Desktop/djprojects/film_manager$

三、查看数据库是否根据牵引文件的需求生成数据库，因此返回终端去连接`filmdatabase`数据库。

boot@boot-virtual-machine:~$ mysql -h 192.168.86.128 -u luyu -p  #以 luyu 的身份进入数据库
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 25
Server version: 8.0.27-0ubuntu0.21.10.1 (Ubuntu)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> use filmdatabase;  #开始使用我们在pycharm 创建的数据库模型类
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;  #显示filmdatabase工程下的所有数据库明细
+----------------------------+
| Tables_in_filmdatabase     |
+----------------------------+
| auth_group                 |
| auth_group_permissions     |
| auth_permission            |
| auth_user                  |
| auth_user_groups           |
| auth_user_user_permissions |
| django_admin_log           |
| django_content_type        |
| django_migrations          |
| django_session             |
| t_filminfo                 |
| t_peopleinfo               |
+----------------------------+
12 rows in set (0.00 sec)

mysql> desc t_filminfo;  #查看 t_filminfo数据库字段情况
+--------------+-------------+------+-----+---------+----------------+
| Field        | Type        | Null | Key | Default | Extra          |
+--------------+-------------+------+-----+---------+----------------+
| fid          | int         | NO   | PRI | NULL    | auto_increment |
| fname        | varchar(20) | NO   |     | NULL    |                |
| playcount    | int         | NO   |     | NULL    |                |
| commentcount | int         | NO   |     | NULL    |                |
| pub_date     | date        | YES  |     | NULL    |                |
| is_delete    | tinyint(1)  | NO   |     | NULL    |                |
+--------------+-------------+------+-----+---------+----------------+
6 rows in set (0.03 sec)

mysql> desc t_peopleinfo;  #查看t_peopleinfo数据库字段情况
+-----------+---------------+------+-----+---------+----------------+
| Field     | Type          | Null | Key | Default | Extra          |
+-----------+---------------+------+-----+---------+----------------+
| uid       | int           | NO   | PRI | NULL    | auto_increment |
| uname     | varchar(10)   | NO   |     | NULL    |                |
| gender    | smallint      | NO   |     | NULL    |                |
| desc      | varchar(2000) | YES  |     | NULL    |                |
| is_delete | tinyint(1)    | NO   |     | NULL    |                |
| film_id   | int           | NO   | MUL | NULL    |                |
+-----------+---------------+------+-----+---------+----------------+
6 rows in set (0.00 sec)

mysql>