import os import sys if __name__ == '__main__': os.environ.setdefault("DJANGO_SETTINGS_MODULE", "ormday71.settings") import django django.setup() from app01 import models ret = models.Employee.objects.all().values("id", "dept") print(ret) from django.db.models import Avg ret = models.Employee.objects.values("dept").annotate(avg=Avg("salary")).values("dept","avg") print(ret) #以什么分组 #得到的值 ret = models.Employee2.objects.values("dept_id").annotate(avg=Avg("salary")).values("dept__name","avg") print(ret) # 查所有的员工和部门名称 ret = models.Employee2.objects.values("name", "dept__name") print(ret) # # ret = models.Employee2.objects.select_related().values("name", "dept__name") # print(ret) # # ret = models.Author.objects.select_related("books__title").values("name", "books__title") # print(ret) # print("=" * 120) # ret = models.Author.objects.prefetch_related("books__title").values("name", "books__title") # print(ret) # 批量创建 # 有100个书籍对象 objs = [models.Book(title="沙河{}".format(i)) for i in range(1500)] # 在数据库中批量创建, 10次一提交 models.Book.objects.bulk_create(objs, 10) # models.Book.objects.all().delete()
from django.shortcuts import render # Create your views here. from app01 import models def books(request): # 从URL取参数 page_num = request.GET.get("page") print(page_num, type(page_num)) # 总数据是多少 total_count = models.Book.objects.all().count() #调用一个类 from utils.mypage import Page page_obj = Page(page_num, total_count, per_page=10, url_prefix="/books/", max_page=9,) ret = models.Book.objects.all()[page_obj.start:page_obj.end] page_html = page_obj.page_html() return render(request, "books.html", {"books":ret, "page_html": page_html}) def depts(request): # 从URL取参数 page_num = request.GET.get("page") print(page_num, type(page_num)) # 总数据是多少 total_count = models.Dept.objects.all().count() from utils.mypage import Page page_obj = Page(page_num, total_count, per_page=10, url_prefix="/depts/", max_page=11, ) ret = models.Dept.objects.all()[page_obj.start:page_obj.end] print(ret) page_html = page_obj.page_html() return render(request, "dept.html", {"depts": ret, "page_html": page_html})
class Page(): def __init__(self, page_num, total_count, url_prefix, per_page=10, max_page=11): """ :param page_num: 当前页码数 :param total_count: 数据总数 :param url_prefix: a标签href的前缀 :param per_page: 每页显示多少条数据 :param max_page: 页面上最多显示几个页码 """ self.url_prefix = url_prefix self.max_page = max_page # 每一页显示多少条数据 # 总共需要多少页码来展示 total_page, m = divmod(total_count, per_page) if m: total_page += 1 self.total_page = total_page try: page_num = int(page_num) # 如果输入的页码数超过了最大的页码数,默认返回最后一页 if page_num > total_page: page_num = total_page except Exception as e: # 当输入的页码不是正经数字的时候 默认返回第一页的数据 page_num = 1 self.page_num = page_num # 定义两个变量保存数据从哪儿取到哪儿 self.data_start = (page_num - 1) * 10 self.data_end = page_num * 10 # 页面上总共展示多少页码 if total_page < self.max_page: self.max_page = total_page half_max_page = self.max_page // 2 # 页面上展示的页码从哪儿开始 page_start = page_num - half_max_page # 页面上展示的页码到哪儿结束 page_end = page_num + half_max_page # 如果当前页减一半 比1还小 if page_start <= 1: page_start = 1 page_end = self.max_page # 如果 当前页 加 一半 比总页码数还大 if page_end >= total_page: page_end = total_page page_start = total_page - self.max_page + 1 self.page_start = page_start self.page_end = page_end @property def start(self): return self.data_start @property def end(self): return self.data_end def page_html(self): # 自己拼接分页的HTML代码 html_str_list = [] # 加上第一页 html_str_list.append('<li><a href="{}?page=1">首页</a></li>'.format( self.url_prefix)) # 判断一下 如果是第一页,就没有上一页 if self.page_num <= 1: html_str_list.append('<li class="disabled"><a href="#"><span aria-hidden="true">«</span></a></li>'.format(self.page_num-1)) else: # 加一个上一页的标签 html_str_list.append('<li><a href="{}?page={}"><span aria-hidden="true">«</span></a></li>'.format( self.url_prefix, self.page_num-1)) for i in range(self.page_start, self.page_end+1): # 如果是当前页就加一个active样式类 if i == self.page_num: tmp = '<li class="active"><a href="{0}?page={1}">{1}</a></li>'.format(self.url_prefix, i) #固定标识,当前页 else: tmp = '<li><a href="{0}?page={1}">{1}</a></li>'.format( self.url_prefix, i) html_str_list.append(tmp) # 加一个下一页的按钮 # 判断,如果是最后一页,就没有下一页 if self.page_num >= self.total_page: html_str_list.append('<li class="disabled"><a href="#"><span aria-hidden="true">»</span></a></li>') else: html_str_list.append('<li><a href="{}?page={}"><span aria-hidden="true">»</span></a></li>'.format( self.url_prefix, self.page_num+1)) # 加最后一页 html_str_list.append('<li><a href="{}?page={}">尾页</a></li>'.format( self.url_prefix, self.total_page)) page_html = "".join(html_str_list) return page_html