django database

时间的设定
from django.db import models
import django.utils.timezone as timezone class Doc(models.Model): add_date = models.DateTimeField('保存日期',default = timezone.now) mod_date = models.DateTimeField('最后修改日期', auto_now = True

 

When the html page reads the DateTimeField field from the database, the displayed time format is inconsistent with the format stored in the database. For example, the content of the database field is 2016-06-03 13:00:00, but the page displays Apr. 03, 2016 , 1 pm

In order to display the same page and database, you need to format the time on the page, you need to add a filter like <td>{{ infor.updatetime|date:"Ymd H:i:s"  }}</td>. Refresh the page to display normally.

from django.db import models
from datetime import datetime
import django.utils.timezone as timezone
# Create your models here.


# 1: 简单用户表 tb_user:
# id , username,userpaw
class user(models.Model):
    user_name = models.CharField(max_length=20)
    user_paw = models.CharField(max_length=20)
    def __str__(self):
        return (self.user_name, self.user_paw)


# 2: 用户详细信息表 tb_userinfo
# id,userid , email , homepage , phone , address ...

class user_info(models.Model):
    user_id = models.ForeignKey("user", on_delete=models.CASCADE)
    email = models.CharField(max_length=30)
    phone = models.CharField(max_length=16)
    sex = models.CharField(max_length=5)
    def __str__(self):
        return (self.user_id, self.email, self.phone, self.sex)



# 3: 论坛主题表 tb_bbs
# id , userid , title , ip , count ,create_time, up
class bbs(models.Model):
    user_id = models.ForeignKey("user",on_delete=models.CASCADE)
    title = models.CharField(max_length=50)
    create_time = models.DateTimeField()
    count = models.IntegerField(default=timezone.now)
    up = models.IntegerField()
    def __str__(self):
        return (self.user_id, self.title, self.create_time, self.count, self.up)


# 4: 论坛内容标 tb_bbs_content (此表可按照bbsid进行分表存储)
# id,bbsid , content;
class bbs_content(models.Model):
    bbs_id = models.ForeignKey("bbs", on_delete=models.CASCADE)
    content = models.CharField(max_length=200)
    def __str__(self):
        return (self.bbs_id, self.content)


# 5: 论坛回复表 tb_bbs_reply (此表可按照bb_sid进行分表存储)
# id , bbs_id , user_id , content , time , ip
class bbs_reply(models.Model):
    bbs_id = models.ForeignKey("bbs", on_delete=models.CASCADE)
    user_id = models.ForeignKey("User", on_delete=models.CASCADE)
    content = models.CharField(max_length=150)
    time = models.DateTimeField(default=timezone.now)
    def __str__(self):
        return (self.bbs_id, self.user_id, self.content, self.time)

表操作

表记录的添加

方式一：
Book()
b=Book(name="python基础",price=99,author="yuan",pub_date="2017-12-12")
b.save()
方式二：
Book.objects.create()
Book.objects.create(name="老男孩linux",price=78,author="oldboy",pub_date="2016-12-12")

表记录的修改
方式一：

b=Book.objects.get(author="oldboy")
b.price=120
b.save()

方式二：
#update是QuerySet
Book.objects.filter(author="yuan").update(price=999)

表记录的删除：
Book.objects.filter(author="oldboy").delete()

表记录的查询（重点）：

book_list = Book.objects.filter(id=2)
book_list=Book.objects.exclude(author="yuan").values("name","price")

book_list=Book.objects.all()
book_list = Book.objects.all()[::2]
book_list = Book.objects.all()[::-1]

#first，last,get取到的是一个实例对象，并非一个QuerySet的集合对象
book_list = Book.objects.first()
book_list = Book.objects.last()
book_list = Book.objects.get(id=2)#只能取出一条记录时才不报错


ret1=Book.objects.filter(author="oldboy").values("name")
ret2=Book.objects.filter(author="yuan").values_list("name","price")

book_list= Book.objects.all().values("name").distinct()
book_count= Book.objects.all().values("name").distinct().count()


模糊查询 双下划线__

book_list=Book.objects.filter(name__icontains="P").values_list("name","price")
book_list=Book.objects.filter(id__gt=5).values_list("name","price")


多表操作（一对多）：
#添加记录
#publish_id=2
Book.objects.create(name="linux运维",price=77,pub_date="2017-12-12",publish_id=2)

#publish=object
Book.objects.create(name="GO",price=23,pub_date="2017-05-12",publish=publish_obj)

#查询记录（通过对象）

正向查询：
book_obj=Book.objects.get(name="python")
pub_obj=book_obj.publish----》书籍对象对应的出版社对象
pub_obj.name
反向查询：
pub_obj = Publish.objects.filter(name="人民出版社")[0]
pub_obj.book_set.all().values("name","price")

#查询记录（filter values 双下划线__）

#人民出版社出版过的书籍与价格
ret=Book.objects.filter(publish__name="人民出版社").values("name","price")

#python这本书出版社的名字
ret2=Publish.objects.filter(book__name="python").values("name")

#python这本书出版社的名字
ret3=Book.objects.filter(name="python").values("publish__name")

#北京的出版社出版书的名字
ret4=Book.objects.filter(publish__city="北京").values("name")

#2017年上半年出版过书的出版社的名字
ret5=Book.objects.filter(pub_date__lt="2017-07-01",pub_date__gt="2017-01-01").values("publish__name")


多表操作（多对多）：

创建多对多的关系 author= models.ManyToManyField("Author")（推荐）


书籍对象它的所有关联作者 obj=book_obj.authors.all()
绑定多对多的关系 obj.add(*QuerySet)
obj.remove(author_obj)


如果想向第三张表插入值的方式绑定关系： 手动创建第三张表

# class Book_Author(models.Model):
# book=models.ForeignKey("Book")
# author=models.ForeignKey("Author")
Book_Author.objects.create(book_id=2,author_id=3)


掌握：通过 filter values (双下换线)进行多对多的关联查询（形式和一对多）