Django 之 ORM 单表查询方法使用

一、在Django项目上运行python文件查询数据库

import os if __name__ == '__main__': #加载Django项目的配置信息 os.environ.setdefault("DJANGO_SETTINGS_MODULE","testinclude.settings") #导入Django,并启动Django项目 import django django.setup() from ormtest import models #查询所有作者 all_author = models.Author.objects.all() print(all_author) #get查询某个人，当值不存在时会报错 person = models.Author.objects.get(id=7) print(person) print("filter".center(60,"*")) #filter返回数据为一个列表，当值不存在时，不会报错，返回一个空的列表 person = models.Author.objects.filter(id=7) print(person) print(person[0]) #exclude 返回id不等于1的所有值，排队法 print("exclude".center(60,"*")) person = models.Author.objects.exclude(id=1) print(person) print("values返回值".center(60,"*")) person = models.Author.objects.values() print(person) print("orderby按照指定的字段排序") person = models.Author.objects.all().order_by("id") print(person) print("count统计匹配的数量".center(60,"*")) count = models.Author.objects.all().count() print(count) print("first返回第一行数据".center(60,"*")) person = models.Author.objects.all().first() print(person) print("last返回最后一行数据".center(60, "*")) person = models.Author.objects.all().last() print(person) print("查询id大于4，小于6的值".center(50,"*")) person = models.Author.objects.filter(id__gt=5,id__lt=7) print(person) print("in查询包括列表中的数或not_in".center(50,"*")) person = models.Author.objects.filter(id__in=[3,5,7]) print(person) print("contains包含某些值".center(50,"*")) person = models.Author.objects.filter(name__contains="周") print(person) print("range相当于sql语句中的between and 5<7".center(50,"*")) person = models.Author.objects.filter(id__range=[5,7]) print(person) 

程序执行结果：

<QuerySet [<Author: author_name:小白>, <Author: author_name:小周>, <Author: author_name:小红>, <Author: author_name:小绿>, <Author: author_name:小光>]> author_name:小光 ***************************filter*************************** <QuerySet [<Author: author_name:小光>]> author_name:小光 **************************exclude*************************** <QuerySet [<Author: author_name:小白>, <Author: author_name:小周>, <Author: author_name:小红>, <Author: author_name:小绿>, <Author: author_name:小光>]> *************************values返回值************************** <QuerySet [{'id': 3, 'name': '小白'}, {'id': 4, 'name': '小周'}, {'id': 5, 'name': '小红'}, {'id': 6, 'name': '小绿'}, {'id': 7, 'name': '小光'}]> orderby按照指定的字段排序 <QuerySet [<Author: author_name:小白>, <Author: author_name:小周>, <Author: author_name:小红>, <Author: author_name:小绿>, <Author: author_name:小光>]> ************************count统计匹配的数量************************ 5 ************************first返回第一行数据************************ author_name:小白 ************************last返回最后一行数据************************ author_name:小光 ******************查询id大于4，小于6的值******************* <QuerySet [<Author: author_name:小绿>]> ****************in查询包括列表中的数或not_in**************** <QuerySet [<Author: author_name:小白>, <Author: author_name:小红>, <Author: author_name:小光>]> ******************contains包含某些值******************* <QuerySet [<Author: author_name:小周>]> **********range相当于sql语句中的between and 5<7********** <QuerySet [<Author: author_name:小红>, <Author: author_name:小绿>, <Author: author_name:小光>]>

models.py文件代码

from django.db import models # Create your models here. class Publisher(models.Model): id = models.AutoField(primary_key=True) name = models.CharField(max_length=64,null=False,unique=True) def __str__(self): return "publisher_name:{}".format(self.name) class Book(models.Model): id = models.AutoField(primary_key=True) title = models.CharField(max_length=128,null=False) publisher = models.ForeignKey(to=Publisher) def __str__(self): return "book_title:{}".format(self.title) class Author(models.Model): id = models.AutoField(primary_key=True) name = models.CharField(max_length=16,null=False) book = models.ManyToManyField(to="Book") def __str__(self): return "author_name:{}".format(self.name)