Django 学习笔记之五 Django中数据库中ManyToManyField及ForeignKey

Posted 2020-08-23 shaomine

1、model里面的代码：

from __future__ import unicode_literals
import django.utils.timezone as timezone
from django.db import models

# Create your models here.
class Publisher(models.Model):
    name = models.CharField(max_length=30)
    address = models.CharField(max_length=30)
    city = models.CharField(max_length=30)

    def __unicode__(self):
        return self.name

class Author(models.Model):
    name = models.CharField(max_length=30)
    email = models.EmailField()

    def __unicode__(self):
        return self.name

class Book(models.Model):
    title = models.CharField(max_length=100)
    author = models.ManyToManyField(Author)
    publisher = models.ForeignKey(Publisher)
    publication = models.DateField(default=timezone.now())

    def __unicode__(self):
        return self.title

2、把数据写入数据库（sqlite）

#coding:utf-8
from django_book.wsgi import *
from book.models import Author,Book,Publisher
import datetime
import random

#初始化作者数据
def InitAuthor():
    namelist = [‘mike‘,‘marry‘,‘jack‘,‘tom‘]
    emaillist =[‘[email protected]‘,‘[email protected]‘,‘[email protected]‘,‘[email protected]‘]
    autherList = []
    for i in range(len(namelist)):
        name = namelist[i];
        email = emaillist[i]
        auther = Author(name=name,email=email)
        autherList.append(auther)
    Author.objects.bulk_create(autherList)

#初始化出版社数据
def InitPublisher():
    namelist = [‘shanghaipublisher‘, ‘beijingpublisher‘, ‘beishidapublisher‘, ‘qinghuapublisher‘]
    citylist = [‘shanghai‘, ‘beijing‘, ‘beijing‘, ‘beijing‘]
    addresslist = [‘shanghai_address‘, ‘beijing_address‘, ‘beijing_address‘, ‘beijing_address‘]
    publisherlist = []
    for i in range(len(namelist)):
        name = namelist[i];
        city = citylist[i]
        address = addresslist[i]
        publisher = Publisher(name=name, city=city,address=address)
        publisherlist.append(publisher)
    Publisher.objects.bulk_create(publisherlist)

#初始化书数据
def InitBook():
    booklist = [‘python‘,‘html‘,‘django‘,‘java‘]
    publisherList = list(Publisher.objects.all())
    authorList = list(Author.objects.all())
    for i in range(len(booklist)):
        title = booklist[i];
        publisher = publisherList[i]
        book, created =Book.objects.get_or_create(title=title,publisher=publisher,
                                                  publication=datetime.datetime.now())
        book.author.add(authorList[i])

def DeleteBook():
    bobj = Book.objects.all()
    bobj.delete()


def main():
    # DeleteBook();
    # InitAuthor()
    # InitPublisher()
    InitBook()

if __name__ == ‘__main__‘:
    main()