更新

Python-100-Days/Day41-55/oa/hrs/views.py

@@ -0,0 +1,47 @@
+from django.http import HttpResponse
+from django.shortcuts import render, redirect
+from django.db.models import ObjectDoesNotExist
+
+from json import dumps
+
+from hrs.models import Dept, Emp
+
+
+def index(request):
+    ctx = {
+        'greeting': '你好，世界！'
+    }
+    return render(request, 'index.html', context=ctx)
+
+
+def del_dept(request, no='0'):
+    try:
+        Dept.objects.get(pk=no).delete()
+        ctx = {'code': 200}
+    except (ObjectDoesNotExist, ValueError):
+        ctx = {'code': 404}
+    return HttpResponse(
+        dumps(ctx), content_type='application/json; charset=utf-8')
+    # 重定向 - 给浏览器一个URL, 让浏览器重新请求指定的页面
+    # return redirect(reverse('depts'))
+    # return depts(request)
+
+
+def emps(request, no='0'):
+    # no = request.GET['no']
+    # dept = Dept.objects.get(no=no)
+    # ForeignKey(Dept, on_delete=models.PROTECT, related_name='emps')
+    # dept.emps.all()
+    # emps_list = dept.emp_set.all()
+    # all() / filter() ==> QuerySet
+    # QuerySet使用了惰性查询 - 如果不是非得取到数据那么不会发出SQL语句
+    # 这样做是为了节省服务器内存的开销 - 延迟加载 - 节省空间势必浪费时间
+    emps_list = list(Emp.objects.filter(dept__no=no).select_related('dept'))
+    ctx = {'emp_list': emps_list, 'dept_name': emps_list[0].dept.name} \
+        if len(emps_list) > 0 else {}
+    return render(request, 'emp.html', context=ctx)
+
+
+def depts(request):
+    ctx = {'dept_list': Dept.objects.all()}
+    return render(request, 'dept.html', context=ctx)