class UsserGroup(models.Model):
    uid = models.AutoField(primary_key=True)
    caption = models.CharField(max_lenght=32, unique=True)

class UserInfo(models.Model):
    username = models.CharField(max_length=32,blank=True,verbose_name = ‘用戶名‘)
    password = models.CharField(max_length=60, help_text=‘
 
pwd‘)
    #外鍵  to_field不寫也行，以默認主鍵  會將user_group生成為user_group_id 數字
    user_group = models.ForeignKey(‘UserGroup‘, to_field = ‘uid‘,default=1,on_delete=models.CASCADE)

    特殊地方 user_group 封裝為一個對象 可以直接調用UserGroup的參數 即user_group.caption    而user_group_id為數字
user_list = Userinfo.objects.all()
for row in
 
 user_list:
    print(row.user_group_id)
    print(row.user_group.uid)
    print(row.user_group.caption)

    #一對多
    #user_list = models.UserInfo.object.all(
    username = ‘root‘
    password=‘123‘,
    user_group_id = ‘1‘  #直接用表裏面user_group中 讓他設置為user_group_id
    )

    讓用戶選擇部門
    group_list = models.UserGroup.object
 
.all()

    在html裏寫
    <form>
    <select name = ‘group_id‘>
        {% for item in group_list %}
            <option value=‘{{item.uid}}‘>{{ item.caption }}</option>
        {% endfor %}
    </select>
    <form>

一對多:
    a.外鍵
    b.外鍵字段_id
    c. models.tb.object.create(name=‘root‘),user_group_id = 1
    d.
        userlist = models.tb.object.all()
        for row in userlist:
            row.id
            row.user_group_id
            row.user_group.caption

django 筆記5 外鍵 ForeignKey