一 准备工作
1.1 新建一个项目
root@darren-virtual-machine:~# cd /root/PycharmProjects/
root@darren-virtual-machine:~/PycharmProjects# django-admin startproject orm_demo
root@darren-virtual-machine:~/PycharmProjects# ll
drwxr-xr-x 7 root root 4096 4月 5 20:04 mysite/ drwxr-xr-x 3 root root 4096 4月 6 13:27 orm_demo/ drwxr-xr-x 3 root root 4096 4月 5 16:27 pymysql/
root@darren-virtual-machine:~/PycharmProjects/orm_demo# python3 manage.py startapp app01
root@darren-virtual-machine:~/PycharmProjects/orm_demo# ll
drwxr-xr-x 3 root root 4096 4月 6 13:29 app01/ drwxr-xr-x 3 root root 4096 4月 6 13:28 .idea/ -rwxr-xr-x 1 root root 628 4月 6 13:27 manage.py* drwxr-xr-x 3 root root 4096 4月 6 13:29 orm_demo/
设置setting.py
root@darren-virtual-machine:~/PycharmProjects/orm_demo# cat orm_demo/settings.py
INSTALLED_APPS = [ 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'app01.apps.App01Config', ]
1.2 创建一个新的数据库
root@darren-virtual-machine:~/PycharmProjects/orm_demo# mysql -uroot -p123456
mysql> create database orm_demo default charset=utf8; Query OK, 1 row affected (0.01 sec) mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | django | | mysql | | orm_demo | | performance_schema | | sys | +--------------------+
配置setting链接数据库
root@darren-virtual-machine:~/PycharmProjects/orm_demo# cat orm_demo/settings.py
DATABASES = { 'default': { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'orm_demo', 'HOST': '127.0.0.1', 'PORT': 3306, 'USER': "root", 'PASSWORD': "123456", } }
导入__init__.py
root@darren-virtual-machine:~/PycharmProjects/orm_demo# cat orm_demo/__init__.py
import pymysql
pymysql.install_as_MySQLdb()
1.3 创建模型
root@darren-virtual-machine:~/PycharmProjects/orm_demo# cat app01/models.py
from django.db import models # Create your models here. class Book(models.Model): title = models.CharField(max_length=32) price = models.DecimalField(max_digits=5, decimal_places=2) pub_date = models.DateField() publish = models.ForeignKey("Publish", on_delete=models.CASCADE) authors = models.ManyToManyField("Author") class Publish(models.Model): name = models.CharField(max_length=32) city = models.CharField(max_length=64) email = models.EmailField() class Author(models.Model): name = models.CharField(max_length=32) age = models.SmallIntegerField() au_detail = models.OneToOneField("AuthorDetail", on_delete=models.CASCADE) class AuthorDetail(models.Model): gender_choices = ( (0, "女"), (1, "男"), (2, "保密"), ) gender = models.SmallIntegerField(choices=gender_choices) tel = models.CharField(max_length=32) addr = models.CharField(max_length=64) birthday = models.DateField()
1.4 执行数据库迁移操作
root@darren-virtual-machine:~/PycharmProjects/orm_demo# python3 manage.py makemigrations
Migrations for 'app01': app01/migrations/0001_initial.py - Create model Author - Create model AuthorDetail - Create model Publish - Create model Book - Add field au_detail to author
root@darren-virtual-machine:~/PycharmProjects/orm_demo# cat app01/migrations/0001_initial.py
# Generated by Django 3.0.5 on 2020-04-06 07:10 from django.db import migrations, models import django.db.models.deletion class Migration(migrations.Migration): initial = True dependencies = [ ] operations = [ migrations.CreateModel( name='Author', fields=[ ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')), ('name', models.CharField(max_length=32)), ('age', models.SmallIntegerField()), ], ), migrations.CreateModel( name='AuthorDetail', fields=[ ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')), ('gender', models.SmallIntegerField(choices=[(0, '女'), (1, '男'), (2, '保密')])), ('tel', models.CharField(max_length=32)), ('addr', models.CharField(max_length=64)), ('birthday', models.DateField()), ], ), migrations.CreateModel( name='Publish', fields=[ ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')), ('name', models.CharField(max_length=32)), ('city', models.CharField(max_length=64)), ('email', models.EmailField(max_length=254)), ], ), migrations.CreateModel( name='Book', fields=[ ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')), ('title', models.CharField(max_length=32)), ('price', models.DecimalField(decimal_places=2, max_digits=5)), ('pub_date', models.DateField()), ('authors', models.ManyToManyField(to='app01.Author')), ('publish', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='app01.Publish')), ], ), migrations.AddField( model_name='author', name='au_detail', field=models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, to='app01.AuthorDetail'), ), ]
root@darren-virtual-machine:~/PycharmProjects/orm_demo# python3 manage.py migrate
Operations to perform:
Apply all migrations: admin, app01, auth, contenttypes, 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 app01.0001_initial... 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 sessions.0001_initial... OK
1.5 查看数据库数据
mysql> use orm_demo mysql> show tables; +----------------------------+ | Tables_in_orm_demo | +----------------------------+ | app01_author | | app01_authordetail | | app01_book | | app01_book_authors | | app01_publish | | 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 | +----------------------------+
四个模型，但是创建了五张表，其中自己创建的表的信息如下
mysql> desc app01_book_authors;
+-----------+---------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------+---------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | book_id | int(11) | NO | MUL | NULL | | | author_id | int(11) | NO | MUL | NULL | | +-----------+---------+------+-----+---------+----------------+
查看数据库表的信息
mysql> desc app01_author -> ; +--------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------+-------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | varchar(32) | NO | | NULL | | | age | smallint(6) | NO | | NULL | | | au_detail_id | int(11) | NO | UNI | NULL | | +--------------+-------------+------+-----+---------+----------------+ 4 rows in set (0.00 sec) mysql> desc app01_authordetail -> ; +----------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+-------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | gender | smallint(6) | NO | | NULL | | | tel | varchar(32) | NO | | NULL | | | addr | varchar(64) | NO | | NULL | | | birthday | date | NO | | NULL | | +----------+-------------+------+-----+---------+----------------+ 5 rows in set (0.01 sec) mysql> desc app01_book; +------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | title | varchar(32) | NO | | NULL | | | price | decimal(5,2) | NO | | NULL | | | pub_date | date | NO | | NULL | | | publish_id | int(11) | NO | MUL | NULL | | +------------+--------------+------+-----+---------+----------------+ 5 rows in set (0.00 sec) mysql> desc app01_book_authors; +-----------+---------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------+---------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | book_id | int(11) | NO | MUL | NULL | | | author_id | int(11) | NO | MUL | NULL | | +-----------+---------+------+-----+---------+----------------+ 3 rows in set (0.00 sec) mysql> desc app01_book_publish; ERROR 1146 (42S02): Table 'orm_demo.app01_book_publish' doesn't exist mysql> desc app01_book_publish;er ERROR 1146 (42S02): Table 'orm_demo.app01_book_publish' doesn't exist -> ^C ^C mysql> desc app01_book_publisher; ERROR 1146 (42S02): Table 'orm_demo.app01_book_publisher' doesn't exist mysql> desc app01_publisher; ERROR 1146 (42S02): Table 'orm_demo.app01_publisher' doesn't exist mysql> desc app01_publish; +-------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | varchar(32) | NO | | NULL | | | city | varchar(64) | NO | | NULL | | | email | varchar(254) | NO | | NULL | | +-------+--------------+------+-----+---------+----------------+