介绍一个简单的功能，就是从web表单里获取用户指定的时间范围，然后在数据库中查询此时间范围内的数据。
        数据库里的model举例是这样：

class book(models.Model): name = models.CharField(max_length=50, unique=True)date = models.DateTimeField()def __unicode__(self): return self.name

假设我们从表单获得的request.GET里面的时间范围最初是这样的：

request.GET = {'year_from': 2010, 'month_from': 1, 'day_from': 1,'year_to':2013, 'month_to': 10, 'day_to': 1}

由于model里保存的date类型是models.DateTimefield(),我们需要先把request里面的数据处理成datetime类型(这是django里响应代码的前半部分)：

import datetimedef filter(request):if 'year_from' and 'month_from' and 'day_from' and\'year_to' and 'month_to' and 'day_to' in request.GET:y = request.GET['year_from']m = request.GET['month_from']d = request.GET['day_from']date_from = datetime.datetime(int(y), int(m), int(d), 0, 0)y = request.GET['year_to']m = request.GET['month_to']d = request.GET['day_to']date_to = datetime.datetime(int(y), int(m), int(d), 0, 0)else:print "error time range!"

接下来就可以用获得的 date_from 和date_to作为端点筛选数据库了，需要用到__range函数,将上面代码加上数据库查询动作：

import datetimedef filter(request):if 'year_from' and 'month_from' and 'day_from' and\'year_to' and 'month_to' and 'day_to' in request.GET:y = request.GET['year_from']m = request.GET['month_from']d = request.GET['day_from']date_from = datetime.datetime(int(y), int(m), int(d), 0, 0)y = request.GET['year_to']m = request.GET['month_to']d = request.GET['day_to']date_to = datetime.datetime(int(y), int(m), int(d), 0, 0)book_list = book.objects.filter(date__range=(date_from, date_to))print book_listelse:print "error time range!"