12-24

ORM的介绍

• modles.py的创建表之间的关系

from django.db import models

# Create your models here.

class Number(models.Model):
    num=models.OneToOneField(to='UserInfo',verbose_name="学号")
    def __str__(self):
        return self.num

class UserInfo(models.Model):
    username=models.CharField(max_length=32,null=True)
    password=models.CharField(max_length=32,null=True)
    def func(self):
        return 'aming_python'

    def __str__(self):
        return  self.name+self.username+self.password

class School(models.Model):
    name=models.CharField(max_length=128,null=True,blank=True,verbose_name="名字")
    mac=models.URLField(max_length=128,default='1',verbose_name="地址")
    email=models.EmailField(max_length=128,null=True,blank=True,verbose_name="邮箱")
    true_fal=models.BooleanField()
    date=models.DateField(verbose_name="是否")
    cla=models.ForeignKey(to='Class',default=1)

class Class(models.Model):
    name=models.CharField(max_length=128,null=True,blank=True,verbose_name="名字")
    user=models.ManyToManyField(to='UserInfo')

• ORM之查

- 查询全部的方式
    def test(request):
        school_li=models.School.objects.all()
        for item in school_li:
            print(item,type(item))
        return HttpResponse('good')
    
aming_linux <class 'test002.models.School'>
aming_python <class 'test002.models.School'>

- get方式

    school=models.School.objects.get(id=1)
    print(school,type(school))

aming_linux <class 'test002.models.School'>

- filter方式

    school=models.School.objects.filter(name='aming_linux')
    print(school, type(school))
    
<QuerySet [<School: aming_linux>]> <class 'django.db.models.query.QuerySet'>

- filter字典的方式
    dic={'name':'aming_linux'}
    obj=models.School.objects.filter(**dic).first()
    print(obj)
    
aming_linux

• ORM之增

- create方式

    obj=models.School.objects.create(**dic)
    print(obj,type(obj))

aming_linux1 <class 'test002.models.School'>

• ORM的删除

    obj=models.School.objects.filter(**dic).delete()
    print(obj,type(obj))
    
(1, {'test002.School': 1}) <class 'tuple'>

• ORM的修改

    dic={'name':'aming_linux'}
    obj=models.School.objects.filter(**dic).update(name='linux_aming')
    print(obj,type(obj))
    
1 <class 'int'>


- 另一种修改的方式

    dic={'name':'aming_linux'}
    obj=models.School.objects.get(name='aming_linux')
    obj.name='linux_aming'
    obj.save()
    print(obj,type(obj))
    
linux_aming <class 'test002.models.School'>