Django基础之Model创建表
一、创建单表
models.py
#!/usr/bin/env python # -*- coding:utf-8 -*- from __future__ import unicode_literals from django.db import models class UserInfo(models.Model): USER_TYPE_LIST = ( (1,"F"), (2,"M"), ) name = models.CharField(max_length=32,primary_key=True) user_type = models.IntegerField(choices=USER_TYPE_LIST,default=1) ctime = models.DateTimeField(auto_now=True) uptime = models.DateTimeField(auto_now_add=True) email = models.EmailField(max_length=32,null=True) email_default = models.EmailField(max_length=32,default="admin@163.com") ip = models.GenericIPAddressField(protocol='both',null=True,blank=True) img = models.ImageField(null=True,blank=True,upload_to="upload") def __unicode__(self): return self.name
创建数据库单表效果如下:
创建用户:
再次查看表数据:
二、创建表之一对多，运用外键models.ForeignKey("xxx")
models.py
Pepole(models.Model):
name = models.CharField(=)
country = models.CharField(=)
Property(models.Model):
size = models.CharField(=)
weight = models.CharField(=)
length = models.CharField(=)
两张表Pepole和Property通过外键models.ForeignKey(Pepole)产生关联
默认通过pepole表的id字段产生关联，property表生成color_id来存放pepole表的id，具体如下:
如果我们在pepole表内生成数据，则会出现如下id:
同时在property表中可以看到关联的项可选数字为1、2、3、4
那一般什么时候用外键呢？比如我们要创建一个业务线，同时也要创建一个主机，但是主机隶属于某个业务线中的一部分，所以这个时候我们可以采取外键的方式创建一对多表，代码如下:
class Business(models.Model):
name = models.CharField(max_length=16)
class Host(models.Model):
hostname = models.CharField(max_length=32)
或者
class Business(models.Model):
name = models.CharField(max_length=16)
class Host(models.Model):
hostname = models.CharField(max_length=32)
也可以通过指定的字段进行绑定
class Business(models.Model):
nid = models.AutoField(primary_key=True)
name = models.CharField(max_length=16,unique=True)
class Host(models.Model):
hostname = models.CharField(max_length=32)
business = models.ForeignKey('Business',to_field='nid')
表Business
表Host
表Host关联字段
三、创建表之多对多，运用models.ManyToManyField('xxxx')
UserGroup(models.Model):
group_name = models.CharField(=)
User(models.Model):
name = models.CharField(=)
email= models.EmailField(=)
user_to_group = models.ManyToManyField()
一个用户可以属于多个用户组，一个用户组可以包含多个用户，建立起多对多的关联关系
UserGroup表:
User表
关联关系:
通过两张表的user_id和usergroup_id来创建关联表user_user_to_group
即通过两张表的代码，系统自动帮忙创建第三张表（关联表user_user_to_group）
四、数据库的常用操作
# 增
①
# models.Tb1.objects.create(c1='xx', c2='oo') 增加一条数据，可以接受字典类型数据 **kwargs
②
# obj = models.Tb1(c1='xx', c2='oo')
# obj.save()
③
dic = {'c1':'xx','c2':'oo'}
models.Tb1.objects.create(**dic)
# 查
#
# models.Tb1.objects.get(id=123) # 获取单条数据，不存在则报错（不建议）
# models.Tb1.objects.all() # 获取全部
# models.Tb1.objects.all().first()# 取第一条数据
# models.Tb1.objects.filter(name='seven') # 获取指定条件的数据
# 删
#
# models.Tb1.objects.filter(name='seven').delete() # 删除指定条件的数据
# 改
①
# models.Tb1.objects.filter(name='seven').update(gender='0') # 将指定条件的数据更新，均支持 **kwargs,支持字典类型数据
②
# obj = models.Tb1.objects.get(id=1)
# obj.c1 = '111'
# obj.save() # 修改单条数据
查询例子:
models.py
SimpleModel(models.Model):
username = models.CharField(=)
password = models.CharField(=)
查询操作home.py
def index(request):
dic = {'username':'pythoner','password':'123!@#'}
models.SimpleModel.objects.create(**dic)
ret = models.SimpleModel.objects.all() #获取所有的数据
print ret #是一个对象的列表[],
print type(ret) #输出结果为django的一个QuerySet类型，
print ret.query #输出一个select查询语句
ret = models.SimpleModel.objects.all().values('username') #只获取某一个列数据，这里获取username列
print ret,type(ret) #这里获取的每一项数据类型是一个字典
#[{'username':'u'alex''}]
ret = models.SimpleModel.objects.all().values_list('username') #这里每一项数据类型就是一个元组
print ret,type(ret)
#[(u'alex',)]
obj = HomeForm.ImportForm()
return render(request,'home/index.html',{'obj':obj})
get data from file
#!/usr/bin/env python
# -*- coding:utf-8 -*-
__author__ = 'ryan'
from django import forms
class ImportForm(forms.Form):
HOST_TYPE_LIST = (
(1,'物理机'),
(2,'虚拟机')
)
host_type = forms.IntegerField(
widget=forms.Select(choices=HOST_TYPE_LIST)
)
hostname = forms.CharField(widget=forms.PasswordInput())
import json
dic = ((1,"abc"),(2,"abcd"),(3,"abcdef"))
f = open('db_admin','w')
f.write(json.dumps(dic))
f.close()
fr = open("db_admin")
data = fr.read()
data_tuple = json.loads(data)
#从文件中获取数据，后期将该部分内容改成sql语句查询结果就成了从数据库中获取数据
admin = forms.IntegerField(
widget=forms.Select(choices=data_tuple)
)
def __init__(self,*args,**kwargs):
super(ImportForm,self).__init__(*args,**kwargs)
#执行父类的构造方法
import json
fr = open("db_admin")
data = fr.read()
data_tuple = json.loads(data)
self.fields['admin'].widget.choice = data_tupleget data from database
#!/usr/bin/env python
# -*- coding:utf-8 -*-
__author__ = 'ryan'
from django import forms
from app01 import models
class ImportForm(forms.Form):
HOST_TYPE_LIST = (
(1,'物理机'),
(2,'虚拟机')
)
host_type = forms.IntegerField(
widget=forms.Select(choices=HOST_TYPE_LIST)
)
hostname = forms.CharField(widget=forms.PasswordInput())
import json
dic = ((1,"abc"),(2,"abcd"),(3,"abcdef"))
f = open('db_admin','w')
f.write(json.dumps(dic))
f.close()
fr = open("db_admin")
data = fr.read()
data_tuple = json.loads(data)
#从文件中获取数据，后期将该部分内容改成sql语句查询结果就成了从数据库中获取数据
admin = forms.IntegerField(
widget=forms.Select(choices=data_tuple)
)
def __init__(self,*args,**kwargs):
super(ImportForm,self).__init__(*args,**kwargs)
self.fields['admin'].widget.choice = models.SimpleModel.objects.all().values_list('id','username')五、数据库的进阶操作
# 获取个数
# models.Tb1.objects.filter(name='seven').count()
# 大于，小于
# models.Tb1.objects.filter(id__gt=1) # 获取id大于1的值
# models.Tb1.objects.filter(id__lt=10) # 获取id小于10的值
# models.Tb1.objects.filter(id__lt=10, id__gt=1) # 获取id大于1 且 小于10的值
# in
# models.Tb1.objects.filter(id__in=[11, 22, 33]) # 获取id等于11、22、33的数据
# models.Tb1.objects.exclude(id__in=[11, 22, 33]) # not in
# contains
# models.Tb1.objects.filter(name__contains="ven")
# models.Tb1.objects.filter(name__icontains="ven") # icontains大小写不敏感
# models.Tb1.objects.exclude(name__icontains="ven")
# range
# models.Tb1.objects.filter(id__range=[1, 2]) # 范围bettwen and
# 其他类似
# startswith，istartswith, endswith, iendswith,
# order by
# models.Tb1.objects.filter(name='seven').order_by('id') # asc
# models.Tb1.objects.filter(name='seven').order_by('-id') # desc
# limit 、offset
# models.Tb1.objects.all()[10:20]
# group by
from django.db.models import Count, Min, Max, Sum
# models.Tb1.objects.filter(c1=1).values('id').annotate(c=Count('num'))
# SELECT "app01_tb1"."id", COUNT("app01_tb1"."num") AS "c" FROM "app01_tb1" WHERE "app01_tb1"."c1" = 1 GROUP BY "app01_tb1"."id"
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