模板:
1 from django.db import models 2 3 class Article(models.Model): 4 title = models.CharField(max_length=200) 5 content = models.TextField() 6 category = models.ForeignKey('Category',on_delete=models.CASCADE,null=True) 7 create_time = models.DateTimeField(auto_now_add=True,null=True) # 保存时获取当前时间 8 class Meta: 9 db_table = 'article' 10 def __str__(self): 11 return "<Article: ID:%s,title:%s,content:%s>" % (self.id,self.title,self.content) 12 13 class Category(models.Model): 14 name = models.CharField(max_length=100) 15 class Meta: 16 db_table = 'category'
视图导入:
1 from django.shortcuts import render 2 from .models import Article,Category 3 from django.http import HttpResponse 4 from datetime import datetime,time,date 5 from django.utils.timezone import make_aware 6 7 def...
数据库内容:
- 使用filter返回QuerySet数据集类型,可调用方法.query;使用get返回一个模型时,不能使用该方法;
- QuerySet.query:‘query’可用来查看这个‘ORM’查询语句最终被翻译成的‘SQL’语句;
- exact/iexact:查找的与原内容完全相等时才能被找到,只是like与=的区别,多数情况下是一样的,可直接省略‘__exact’;
1 def index(requset): 2 article = Article.objects.filter(title__exact='三国演义') 3 article = Article.objects.filter(title__iexact='三国演义') 4 print(article.query) 5 print(type(article)) 6 return HttpResponse('success') 7 # >>> SELECT `article`.`id`, `article`.`title`, `article`.`content` FROM `article` WHERE `article`.`title` = 三国演义 8 # >>> SELECT `article`.`id`, `article`.`title`, `article`.`content` FROM `article` WHERE `article`.`title` LIKE 三国演义 9 # <class 'django.db.models.query.QuerySet'>
- contains/icontains:只要包含有查找的内容就能被找到;
1 def index1(request): 2 result = Article.objects.filter(title__contains='hello') 3 print(result.query) 4 return HttpResponse('success') 5 # 使用contains区分大小写,icontains不区分; 6 # SELECT `article`.`id`, `article`.`title`, `article`.`content` FROM `article` WHERE `article`.`title` LIKE BINARY %hello%
- in:查找in中所包含的内容
1 def index2(requset): 2 # 1、查找id为1,2,3的文章 3 articles = Articel.objects.filter(id__in=[1,2,3]) 4 for article in articles: 5 print(article) 6 7 # 2、查找文章id为1,2,3的分类;'__id'可省略;article_in中的‘article’反向查询可用‘related_query_name’改名, 8 # 类似于‘related_name’的用法,改后仍需加‘__in’; 9 category = Category.objects.filter(articel__id__in=[1,2,3]) 10 11 # 查找所有包含hello的分类 12 articles = Article.objects.filter(title__icontains='hello') 13 categorys = Category.objects.filter(article__in=articles) 14 for category in categorys: 15 print(category) 16 return HttpResponse('success')
- gt/gte、lt/lte:大于/大于等于、小于/小于等于;(greater/lower than equal)
1 article = Article.objects.filter(id__gt=2) 2 # startswith/endswith:以什么开头或结尾,前面加‘i’表不区分大小写; 3 articles = Article.objects.filter(title__startswith='hello') 4 return HttpResponse('success')
- range:需指定时间段,时间应标记为‘aware’时间。(make_aware(value,timezone=None,is_dst=None):没有传入时区时,将获取当前的时区:timezone = get_current_timezone();即获取settings.py中‘TIME_ZONE = 'Asia/Shanghai'’设置的时区;)
1 def index5(requset): 2 start_time = make_aware(datetime(year=2019,month=3,day=7,hour=15,minute=0,second=0)) 3 end_time = make_aware(datetime(year=2019,month=3,day=7,hour=16,minute=0,second=0)) 4 articles = Article.objects.filter(creat_time__range=(start_time,end_time)) 5 print(articles.query) 6 print(articles) 7 return HttpResponse('success')
- DATE:将create_time的datetime类型转换为DATE的类型;
1 def index6(request): 2 article = Article.objects.filter(create_time__date=date(year=2019,month=3,day=7)) 3 print(article.query) 4 print(article) 5 return HttpResponse('success')
1 # CONVERT_TZ:将时间从UTC的时区转换为Asia/Shanghai的时区;因MySQL本身不具备这些时区的信息,所以相当于 2 # 转换失败,需将具有该信息的文件拷贝进mysql中。 3 # 在官网https://dev.mysql.com/downloads/timezones.html中下载文件timezone_2018i_posix.zip - POSIX standard解压后拷贝覆盖 4 # 到:C:ProgramDataMySQLMySQL Server 5.7Datamysql 路径下(先将原文件保存); 5 # 后重启数据库,使用命令:set stop/start [mysql数据库名] 进行重启(可在服务中查看数据库名字); 6 # Linux或Mac中執行命令:mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -D mysql -u root -p 密码;(数据库,用户,密码) 7 # 错误输出:<QuerySet []> 8 # 正常输出: 9 # SELECT `article`.`id`, `article`.`title`, `article`.`content`, `article`.`category_id`, `article`.`create_time` FROM 10 # `article` WHERE DATE(CONVERT_TZ(`article`.`create_time`, 'UTC', 'Asia/Shanghai')) = 2019-03-07 11 # <QuerySet [<Article: <Article: ID:1,title:西游记,content:abc...>>,<Article: <Article: ID:2,title:三国演义,content:123...>>, <Article: <Article: ID:3,title:Hello world,content:xxx>>,<Article: <Article: ID:4,title:英文单词:hello,content:aaa>>, <Article: <Article: ID:5,title:红楼梦,content:aaa...>>]>
1 def index7(request): 2 # 查找某个时间的数据,因秒(second)需精确到小数位,所以用range方法; 3 # article = Article.objects.filter(create_time__time=time(hour=15, minute=29, second=15)) 4 start_time = time(hour=15,minute=29,second=15) 5 end_time = time(hour=15,minute=29,second=16) 6 article = Article.objects.filter(create_time__time__range=(start_time,end_time)) 7 print(article) 8 return HttpResponse('success')
- regex:使用正则表达式
1 def index8(request): 2 # regex 表示区分大小写 3 articles = Article.objects.filter(title__iregex=r"^hello") 4 print(articles)