S11 day 97 -98天 Luffycity项目

1. 建模

from django.db import models
from django.contrib.contenttypes.fields import GenericForeignKey,GenericRelation
from  django.contrib.contenttypes.models import ContentType

# Create your models here.

class CourseCategory(models.Model):
    """
        课程大类, e.g 前端 后端...
    """
    name =models.CharField(max_length=64,unique=True)

    def __str__(self):
        return "%s" %self.name

    class Meta:
        verbose_name_plural ="01.课程大纲"

class CourseSubCategory(models.Model):
    # 课程子类，e.g python linux
    category =models.ForeignKey("CourseCategory")
    name =models.CharField(max_length=64,unique=True)

    def __str__(self):
        return "%s" % self.name

    class Meta:
        verbose_name_plural="02.课程子类"

class DegreeCourse(models.Model):
    """
    学位课
    """
    name =models.CharField(max_length=128,unique=True)
    course_img =models.CharField(max_length=255,verbose_name="缩略图")
    brief =models.TextField(verbose_name="学位课程简介",)
    total_scholarship =models.PositiveIntegerField(verbose_name="总奖金（贝里）",default=40000)
    mentor_compensation_bonus =models.PositiveIntegerField(verbose_name="本课程的倒是辅导费用(贝里)",default=15000)
    period = models.PositiveIntegerField(verbose_name="建议学习周期(days)",default=150)#为了计算学位奖学金
    prerequisite=models.TextField(verbose_name="课程先修要求",max_length=1024)
    teachers = models.ManyToManyField("Teacher",verbose_name="课程讲师")

    #用于GenericForeignKey反向查询,不会生成表字段，切勿删除
    # coupon =GenericRelation("Coupon")

    #用于GenricForeignKey反向查询，不会产生字段，切勿删除.
    degreecourse_price_policy =GenericRelation("PricePolicy")

    def __str__(self):
        return  self.name

    class Meta:
        verbose_name_plural= "03.学位课"

class Teacher(models.Model):
    #讲师、导师表
    name =models.CharField(max_length=32)
    role_choices =((0,"讲师"),(1,"导师"))
    role = models.SmallIntegerField(choices=role_choices,default=0 )
    title =models.CharField(max_length=64,verbose_name="职位，职称")
    signature= models.CharField(max_length=255,help_text="导师签名",blank=True,null=True)
    image =models.CharField(max_length=128)
    brief =models.TextField(max_length=1024)

    def __str__(self):
        return self.name
    class Meta:
        verbose_name_plural="04.导师或讲师"

class Scholarship(models.Model):
    #学位课程奖学金
    degree_course=models.ForeignKey("DegreeCourse")
    time_percent =models.PositiveIntegerField(verbose_name="奖励档位（时间百分比）",help_text="只填百分之，如80，代表80%")
    value =models.PositiveIntegerField(verbose_name="奖学金数额")

    def __str__(self):
        return "%s:%s"%(self.degree_course,self.value)

    class Meta:
        verbose_name_plural ="05.学位课奖学金"

class Course(models.Model):
    #专业课程
    name = models.CharField(max_length=128,unique=True)
    course_img =models.CharField(max_length=255)
    sub_category =models.ForeignKey("CourseSubCategory")
    course_type_choice =((0,"付费"),(1,"vip专享"),(2,"学位课程"))
    course_type =models.SmallIntegerField(choices=course_type_choice)
    degree_course =models.ForeignKey("DegreeCourse",blank=True,null= True,help_text="若是学位课程，此处关联学位表")
    brief =models.TextField(verbose_name="课程概述",max_length=2048)
    level_choices =((0,"初级"),(1,"中级"),(2,"高级"))
    level =models.SmallIntegerField(choices=level_choices,default=1 )
    pub_date =models.DateField(verbose_name="发布时间",blank=True,null=True)
    period = models.PositiveIntegerField(verbose_name="建议学习周期（days）",default=7)
    order =models.IntegerField("课程顺序",help_text="从上一个课程往后排")
    attachment_patch =models.CharField(max_length=128,verbose_name="课程路径",blank=True,null=True)
    status_choice =((0,"上线"),(1,"下线"),(2,"预上线"))
    template_id=models.SmallIntegerField(choices=status_choice,default=0 )
    # coupon =GenericRelation("Coupon")
    #用于GenericForeignKey反向查询，不会生成表字段，切勿删除.
    price_policy=GenericRelation("PricePolicy")

    asked_question =GenericRelation("OftenAskedQuestion")

    def __str__(self):
        return "%s(%s)"%(self.name ,self.get_course_type_display())

    def save(self, *args ,**kwargs):
        if self.course_type==2 :
            if not self.degree_course:
                raise ValueError("学位课程必须关联对应的学位表")
        super(Course, self).save(*args,**kwargs)

    class Meta:
        verbose_name_plural="06.专题课程或学位课程模块"

class CourseDetail(models.Model):
    """课程详情页内容"""
    course = models.OneToOneField("Course")
    hours = models.IntegerField("课时")
    course_slogan = models.CharField(max_length=125, blank=True, null=True)
    video_brief_link = models.CharField(verbose_name='课程介绍', max_length=255, blank=True, null=True)
    why_study = models.TextField(verbose_name="为什么学习这门课程")
    what_to_study_brief = models.TextField(verbose_name="我将学到哪些内容")
    career_improvement = models.TextField(verbose_name="此项目如何有助于我的职业生涯")
    prerequisite = models.TextField(verbose_name="课程先修要求", max_length=1024)
    recommend_courses = models.ManyToManyField("Course", related_name="recommend_by", blank=True)
    teachers = models.ManyToManyField("Teacher", verbose_name="课程讲师")

    def __str__(self):
        return "%s" % self.course

    class Meta:
        verbose_name_plural = "07.课程或学位模块详细"

class OftenAskedQuestion(models.Model):
    """常见问题"""
    content_type = models.ForeignKey(ContentType,
                                     limit_choices_to={'model__contains': 'course'})  # 关联course or degree_course
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

    question = models.CharField(max_length=255)
    answer = models.TextField(max_length=1024)

    def __str__(self):
        return "%s-%s" % (self.content_object, self.question)

    class Meta:
        unique_together = ('content_type', 'object_id', 'question')
        verbose_name_plural = "08. 常见问题"

class CourseOutline(models.Model):
    """课程大纲"""
    course_detail = models.ForeignKey("CourseDetail")
    title = models.CharField(max_length=128)
    # 前端显示顺序
    order = models.PositiveSmallIntegerField(default=1)

    content = models.TextField("内容", max_length=2048)

    def __str__(self):
        return "%s" % self.title

    class Meta:
        unique_together = ('course_detail', 'title')
        verbose_name_plural = "09. 课程大纲"

class CourseChapter(models.Model):
    """课程章节"""
    course = models.ForeignKey("Course", related_name='coursechapters')
    chapter = models.SmallIntegerField(verbose_name="第几章", default=1)
    name = models.CharField(max_length=128)
    summary = models.TextField(verbose_name="章节介绍", blank=True, null=True)
    pub_date = models.DateField(verbose_name="发布日期", auto_now_add=True)

    class Meta:
        unique_together = ("course", 'chapter')
        verbose_name_plural = "10. 课程章节"

    def __str__(self):
        return "%s:(第%s章)%s" % (self.course, self.chapter, self.name)

class CourseSection(models.Model):
    """课时目录"""
    chapter = models.ForeignKey("CourseChapter", related_name='coursesections')
    name = models.CharField(max_length=128)
    order = models.PositiveSmallIntegerField(verbose_name="课时排序", help_text="建议每个课时之间空1至2个值，以备后续插入课时")
    section_type_choices = ((0, '文档'), (1, '练习'), (2, '视频'))
    section_type = models.SmallIntegerField(default=2, choices=section_type_choices)
    section_link = models.CharField(max_length=255, blank=True, null=True, help_text="若是video，填vid,若是文档，填link")
    video_time = models.CharField(verbose_name="视频时长", blank=True, null=True, max_length=32)  # 仅在前端展示使用
    pub_date = models.DateTimeField(verbose_name="发布时间", auto_now_add=True)
    free_trail = models.BooleanField("是否可试看", default=False)

    class Meta:
        unique_together = ('chapter', 'section_link')
        verbose_name_plural = "11. 课时"

    def __str__(self):
        return "%s-%s" % (self.chapter, self.name)

class Homework(models.Model):
    chapter = models.ForeignKey("CourseChapter")
    title = models.CharField(max_length=128, verbose_name="作业题目")
    order = models.PositiveSmallIntegerField("作业顺序", help_text="同一课程的每个作业之前的order值间隔1-2个数")
    homework_type_choices = ((0, '作业'), (1, '模块通关考核'))
    homework_type = models.SmallIntegerField(choices=homework_type_choices, default=0)
    requirement = models.TextField(max_length=1024, verbose_name="作业需求")
    threshold = models.TextField(max_length=1024, verbose_name="踩分点")
    recommend_period = models.PositiveSmallIntegerField("推荐完成周期(天)", default=7)
    scholarship_value = models.PositiveSmallIntegerField("为该作业分配的奖学金(贝里)")
    note = models.TextField(blank=True, null=True)
    enabled = models.BooleanField(default=True, help_text="本作业如果后期不需要了，不想让学员看到，可以设置为False")

    class Meta:
        unique_together = ("chapter", "title")
        verbose_name_plural = "12. 章节作业"

    def __str__(self):
        return "%s - %s" % (self.chapter, self.title)

class PricePolicy(models.Model):
    """价格与有课程效期表"""
    content_type = models.ForeignKey(ContentType)  # 关联course or degree_course
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

    # course = models.ForeignKey("Course")
    valid_period_choices = ((1, '1天'), (3, '3天'),
                            (7, '1周'), (14, '2周'),
                            (30, '1个月'),
                            (60, '2个月'),
                            (90, '3个月'),
                            (180, '6个月'), (210, '12个月'),
                            (540, '18个月'), (720, '24个月'),
                            )
    valid_period = models.SmallIntegerField(choices=valid_period_choices)
    price = models.FloatField()

    class Meta:
        unique_together = ("content_type", 'object_id', "valid_period")
        verbose_name_plural = "15. 价格策略"

    def __str__(self):
        return "%s(%s)%s" % (self.content_object, self.get_valid_period_display(), self.price)

2. settings设置

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'app01.apps.App01Config',
    'api.apps.ApiConfig',
    "rest_framework"
]

3. url 路径

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^api/(?P<version>w+)/', include("api.api_url")),
]

from api.views import course

urlpatterns=[
    url(r'courses/',course.CourseView.as_view()),
    # url(r'courses/(?P<pk>d+)',course.CourseView.as_view())
]

4. 在admin文件中注册

from django.contrib import admin

# Register your models here.
from api.models import *

admin.site.register(CourseCategory)
admin.site.register(CourseSubCategory)
admin.site.register(DegreeCourse)
admin.site.register(Teacher)
admin.site.register(Scholarship)
admin.site.register(Course)
admin.site.register(CourseDetail)
admin.site.register(OftenAskedQuestion)
admin.site.register(CourseOutline)
admin.site.register(CourseChapter)
admin.site.register(CourseSection)
admin.site.register(Homework)
admin.site.register(PricePolicy)

5. views 逻辑函数 方法一、json.dumps

from django.shortcuts import HttpResponse
from rest_framework.views import APIView
import json

from api import models
class CourseView(APIView):
    def get(self,request,*args,**kwargs):

        #方式一：
        course_list =list(models.Course.objects.all().values("id","name"))
        return HttpResponse(json.dumps(course_list,ensure_ascii=False))

输出结果：

6. views逻辑函数 方法二、 序列化

　　创建序列化的文档 course

from rest_framework import serializers

class CourseSerializer(serializers.Serializer):
    id = serializers.IntegerField()
    name =serializers.CharField()

第二种方式序列化 modelserializer

#序列化方式二，一对一跨表 和一对多跨表，还有多选项(get_xx_display)
class CourseModelSerializer(serializers.ModelSerializer):
    level_name =serializers.CharField(source="get_level_display")  #choice选项的序列化
    hours = serializers.CharField(source="coursedetail.hours") #一对一跨表查询hours字段
    course_slogan =serializers.CharField(source="coursedetail.course_slogan")
    class Meta:
        model =models.Course
        fields =["id","name","level_name","hours","course_slogan",]

view视图

from django.shortcuts import HttpResponse
from rest_framework.views import APIView
from api.serializers.course import CourseSerializer
from api import models
class CourseView(APIView):
    def get(self,request,*args,**kwargs):
        # 方法二：
        course_list =models.Course.objects.all()
        ser =CourseSerializer(instance=course_list,many=True)
        return HttpResponse(ser.data)

输出结果

第三种方法（查询所有Course的API）

from rest_framework.views import APIView
from rest_framework.versioning import URLPathVersioning
from api.serializers.course import CourseSerializer
from api import models
from rest_framework.response import Response
class CourseView(APIView):
    def get(self,request,*args,**kwargs):
        course_list =models.Course.objects.all()
        ser = CourseSerializer(instance=course_list,many =True)
        return Response(ser.data)

输出结果：

增加分页功能

from rest_framework.pagination import PageNumberPagination


class CourseView(APIView):
    def get(self,request,*args,**kwargs):
        #从数据库中获取数据
        course_list =models.Course.objects.all()
        #分页
        page =PageNumberPagination()
        page.paginate_queryset(course_list,request,self)
        #序列化
        ser = CourseSerializer(instance=course_list,many =True)
        return Response(ser.data)

增加异常处理1. ：

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        response ={"code":1000,"data":None,"error":None}
        try:
            # 从数据库中获取数据
            course_list = models.Course.objects.all()
            # 分页
            page = PageNumberPagination()
            page.paginate_queryset(course_list, request, self)
            # 序列化
            ser = CourseSerializer(instance=course_list, many=True)

            response["data"] =ser.data
        except Exception as e:
            response["code"] =500
            response["error"] ="获取数据失败"

        return Response(response)

 增加异常处理方法2

from django.shortcuts import HttpResponse
from rest_framework.views import APIView
from rest_framework.versioning import URLPathVersioning
from api.serializers.course import CourseSerializer
from rest_framework.pagination import PageNumberPagination
from api import models
from rest_framework.response import Response
from api.utils.response import BaseResponse

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        # response ={"code":1000,"data":None,"error":None}
        ret =BaseResponse()
        try:
            # 从数据库中获取数据
            course_list = models.Course.objects.all()
            # 分页
            page = PageNumberPagination()
            page.paginate_queryset(course_list, request, self)
            # 序列化
            ser = CourseSerializer(instance=course_list, many=True)

            # response["data"] =ser.data
            ret.data =ser.data
        except Exception as e:
            # response["code"] =500
            ret.code =500
            # response["error"] ="获取数据失败"
            ret.error ="获取数据失败"

        return Response(ret.dict)

 分页配置（三行代码）

REST_FRAMEWORK ={
    'DEFAULT_VERSIONING_CLASS': 'rest_framework.versioning.URLPathVersioning',
    'VERSION_PARAM': 'version',
    'DEFAULT_VERSION': 'v1',
    'ALLOWED_VERSIONS': ['v1', 'v2'],
    'PAGE_SIZE': 1
}

class CourseView(APIView):
    def get(self, request, *args, **kwargs):
        # response ={"code":1000,"data":None,"error":None}
        ret =BaseResponse()
        try:
            # 从数据库中获取数据
            query_set = models.Course.objects.all()
            # 分页
            page = PageNumberPagination()
            course_list=page.paginate_queryset(query_set, request, self)
            # 序列化
            ser = CourseModelSerializer(instance=course_list, many=True)
            # response["data"] =ser.data
            ret.data =ser.data
        except Exception as e:
            # response["code"] =500
            ret.code =500
            # response["error"] ="获取数据失败"
            ret.error ="获取数据失败"

        return Response(ret.dict)

结果：

最后一种方法是 ModelViewSet，但是我们暂时不要用， 那种方式是最简单的，所有的功能都在源码里封装好了，初学者使用APIview进行训练。

 查询某个Course的API

1. url

urlpatterns=[
    url(r'courses/$',course.CourseView.as_view()),
    url(r'courses/(?P<pk>d+)',course.CourseDetailView.as_view())
]

view视图

from rest_framework.views import APIView
from api.serializers.course import CourseSerializer
from api import models
from rest_framework.response import Response

class CourseDetailView(APIView):
    def get(self,request,pk,*args,**kwargs):
        course =models.Course.objects.get(id =pk)
        ser =CourseSerializer(instance=course)
        return Response(ser.data)

输出结果为：

序列化：DegreeCourse表的序列化

from rest_framework import serializers
from api import  models
#序列化方式二，一对一跨表 和一对多跨表，还有多选项(get_xx_display)
class DegreeCourseModelSerializer(serializers.ModelSerializer):
    name =serializers.CharField()
    teachers_name =serializers.SerializerMethodField() # 多对多查询
    class Meta:
        model =models.Course
        fields =["name","teachers_name",]


    def get_teachers_name(self,row):
        teachers_list = row.teachers.all()
        return [ {"name":item.name} for item in teachers_list]

 序列化 course表序列化

from rest_framework import serializers
from api import  models

#序列化方式一
class CourseSerializer(serializers.Serializer):
    id = serializers.IntegerField()
    name =serializers.CharField()

#序列化方式二，一对一跨表 和一对多跨表，还有多选项(get_xx_display)
class CourseModelSerializer(serializers.ModelSerializer):
    id = serializers.IntegerField()
    name =serializers.CharField()
    level_name =serializers.CharField(source="get_level_display")  #choice选项的序列化
    hours = serializers.CharField(source="coursedetail.hours") #一对一跨表查询hours字段
    course_slogan =serializers.CharField(source="coursedetail.course_slogan") # 一对一跨表查询
    # recommend_courses1 = serializers.SerializerMethodField()#多对多跨表查询

    class Meta:
        model =models.Course
        # fields =["id","name","level_name","hours","course_slogan",]
        fields =["id","name","level_name","hours","course_slogan",]
        # fields =["id","name","level_name","hours","course_slogan","recommend_courses1"]
    #
    # def get_recommend_courses1(self, row):
    #     recommend_list =row.coursedetail.recommend_courses.all()
    #     return [ {"id":item.id ,"name":item.name} for item in recommend_list ]

 ORM查询练习

from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
from django.contrib.contenttypes.models import ContentType
from django.db.models import Q
from django.utils.safestring import mark_safe
from django.db import models
import hashlib


# ######################## 课程相关 ########################

class CourseCategory(models.Model):
    """课程大类, e.g 前端  后端..."""
    name = models.CharField(max_length=64, unique=True)

    def __str__(self):
        return "%s" % self.name

    class Meta:
        verbose_name_plural = "01.课程大类"


class CourseSubCategory(models.Model):
    """课程子类, e.g python linux """
    category = models.ForeignKey("CourseCategory")
    name = models.CharField(max_length=64, unique=True)

    def __str__(self):
        return "%s" % self.name

    class Meta:
        verbose_name_plural = "02.课程子类"


class DegreeCourse(models.Model):
    """学位课程"""
    name = models.CharField(max_length=128, unique=True)
    course_img = models.CharField(max_length=255, verbose_name="缩略图")
    brief = models.TextField(verbose_name="学位课程简介", )
    total_scholarship = models.PositiveIntegerField(verbose_name="总奖学金(贝里)", default=40000)  # 2000 2000
    mentor_compensation_bonus = models.PositiveIntegerField(verbose_name="本课程的导师辅导费用(贝里)", default=15000)
    period = models.PositiveIntegerField(verbose_name="建议学习周期(days)", default=150)  # 为了计算学位奖学金
    prerequisite = models.TextField(verbose_name="课程先修要求", max_length=1024)
    teachers = models.ManyToManyField("Teacher", verbose_name="课程讲师")

    # 用于GenericForeignKey反向查询， 不会生成表字段，切勿删除
    # coupon = GenericRelation("Coupon")

    # 用于GenericForeignKey反向查询，不会生成表字段，切勿删除
    degreecourse_price_policy = GenericRelation("PricePolicy")

    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = "03.学位课"


class Teacher(models.Model):
    """讲师、导师表"""
    name = models.CharField(max_length=32)
    role_choices = ((0, '讲师'), (1, '导师'))
    role = models.SmallIntegerField(choices=role_choices, default=0)
    title = models.CharField(max_length=64, verbose_name="职位、职称")
    signature = models.CharField(max_length=255, help_text="导师签名", blank=True, null=True)
    image = models.CharField(max_length=128)
    brief = models.TextField(max_length=1024)

    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = "04.导师或讲师"


class Scholarship(models.Model):
    """学位课程奖学金"""
    degree_course = models.ForeignKey("DegreeCourse")
    time_percent = models.PositiveSmallIntegerField(verbose_name="奖励档位(时间百分比)", help_text="只填百分值，如80,代表80%")
    value = models.PositiveIntegerField(verbose_name="奖学金数额")

    def __str__(self):
        return "%s:%s" % (self.degree_course, self.value)

    class Meta:
        verbose_name_plural = "05.学位课奖学金"


class Course(models.Model):
    """专题课/学位课模块表"""
    name = models.CharField(max_length=128, unique=True)
    course_img = models.CharField(max_length=255)
    sub_category = models.ForeignKey("CourseSubCategory")
    course_type_choices = ((0, '付费'), (1, 'VIP专享'), (2, '学位课程'))
    course_type = models.SmallIntegerField(choices=course_type_choices)

    # 不为空；学位课的某个模块
    # 为空；专题课
    degree_course = models.ForeignKey("DegreeCourse", blank=True, null=True, help_text="若是学位课程，此处关联学位表")

    brief = models.TextField(verbose_name="课程概述", max_length=2048)
    level_choices = ((0, '初级'), (1, '中级'), (2, '高级'))
    level = models.SmallIntegerField(choices=level_choices, default=1)
    pub_date = models.DateField(verbose_name="发布日期", blank=True, null=True)
    period = models.PositiveIntegerField(verbose_name="建议学习周期(days)", default=7)  #
    order = models.IntegerField("课程顺序", help_text="从上一个课程数字往后排")
    attachment_path = models.CharField(max_length=128, verbose_name="课件路径", blank=True, null=True)
    status_choices = ((0, '上线'), (1, '下线'), (2, '预上线'))
    status = models.SmallIntegerField(choices=status_choices, default=0)
    template_id = models.SmallIntegerField("前端模板id", default=1)

    # coupon = GenericRelation("Coupon")

    # 用于GenericForeignKey反向查询，不会生成表字段，切勿删除
    price_policy = GenericRelation("PricePolicy")

    asked_question = GenericRelation("OftenAskedQuestion")


    def __str__(self):
        return "%s(%s)" % (self.name, self.get_course_type_display())


    def save(self, *args, **kwargs):
        if self.course_type == 2:
            if not self.degree_course:
                raise ValueError("学位课程必须关联对应的学位表")
        super(Course, self).save(*args, **kwargs)


    class Meta:
        verbose_name_plural = "06.专题课或学位课模块"


class CourseDetail(models.Model):
    """课程详情页内容"""
    course = models.OneToOneField("Course")
    hours = models.IntegerField("课时")
    course_slogan = models.CharField(max_length=125, blank=True, null=True)
    video_brief_link = models.CharField(verbose_name='课程介绍', max_length=255, blank=True, null=True)
    why_study = models.TextField(verbose_name="为什么学习这门课程")
    what_to_study_brief = models.TextField(verbose_name="我将学到哪些内容")
    career_improvement = models.TextField(verbose_name="此项目如何有助于我的职业生涯")
    prerequisite = models.TextField(verbose_name="课程先修要求", max_length=1024)
    recommend_courses = models.ManyToManyField("Course", related_name="recommend_by", blank=True)
    teachers = models.ManyToManyField("Teacher", verbose_name="课程讲师")

    def __str__(self):
        return "%s" % self.course

    class Meta:
        verbose_name_plural = "07.课程或学位模块详细"


class OftenAskedQuestion(models.Model):
    """常见问题"""
    content_type = models.ForeignKey(ContentType)  # 关联course or degree_course
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

    question = models.CharField(max_length=255)
    answer = models.TextField(max_length=1024)


    def __str__(self):
        return "%s-%s" % (self.content_object, self.question)


    class Meta:
        unique_together = ('content_type', 'object_id', 'question')
        verbose_name_plural = "08. 常见问题"


class CourseOutline(models.Model):
    """课程大纲"""
    course_detail = models.ForeignKey("CourseDetail")
    title = models.CharField(max_length=128)
    # 前端显示顺序
    order = models.PositiveSmallIntegerField(default=1)

    content = models.TextField("内容", max_length=2048)

    def __str__(self):
        return "%s" % self.title

    class Meta:
        unique_together = ('course_detail', 'title')
        verbose_name_plural = "09. 课程大纲"


class CourseChapter(models.Model):
    """课程章节"""
    course = models.ForeignKey("Course",related_name='xxxxx') #
    chapter = models.SmallIntegerField(verbose_name="第几章", default=1)
    name = models.CharField(max_length=128)
    summary = models.TextField(verbose_name="章节介绍", blank=True, null=True)
    pub_date = models.DateField(verbose_name="发布日期", auto_now_add=True)

    class Meta:
        unique_together = ("course", 'chapter')
        verbose_name_plural = "10. 课程章节"

    def __str__(self):
        return "%s:(第%s章)%s" % (self.course, self.chapter, self.name)


class CourseSection(models.Model):
    """课时目录"""
    chapter = models.ForeignKey("CourseChapter", related_name='coursesections')
    name = models.CharField(max_length=128)
    order = models.PositiveSmallIntegerField(verbose_name="课时排序", help_text="建议每个课时之间空1至2个值，以备后续插入课时")
    section_type_choices = ((0, '文档'), (1, '练习'), (2, '视频'))
    section_type = models.SmallIntegerField(default=2, choices=section_type_choices)
    section_link = models.CharField(max_length=255, blank=True, null=True, help_text="若是video，填vid,若是文档，填link")
    video_time = models.CharField(verbose_name="视频时长", blank=True, null=True, max_length=32)  # 仅在前端展示使用
    pub_date = models.DateTimeField(verbose_name="发布时间", auto_now_add=True)
    free_trail = models.BooleanField("是否可试看", default=False)

    class Meta:
        unique_together = ('chapter', 'section_link')
        verbose_name_plural = "11. 课时"

    def __str__(self):
        return "%s-%s" % (self.chapter, self.name)


class Homework(models.Model):
    chapter = models.ForeignKey("CourseChapter")
    title = models.CharField(max_length=128, verbose_name="作业题目")
    order = models.PositiveSmallIntegerField("作业顺序", help_text="同一课程的每个作业之前的order值间隔1-2个数")
    homework_type_choices = ((0, '作业'), (1, '模块通关考核'))
    homework_type = models.SmallIntegerField(choices=homework_type_choices, default=0)
    requirement = models.TextField(max_length=1024, verbose_name="作业需求")
    threshold = models.TextField(max_length=1024, verbose_name="踩分点")
    recommend_period = models.PositiveSmallIntegerField("推荐完成周期(天)", default=7)
    scholarship_value = models.PositiveSmallIntegerField("为该作业分配的奖学金(贝里)")
    note = models.TextField(blank=True, null=True)
    enabled = models.BooleanField(default=True, help_text="本作业如果后期不需要了，不想让学员看到，可以设置为False")

    class Meta:
        unique_together = ("chapter", "title")
        verbose_name_plural = "12. 章节作业"

    def __str__(self):
        return "%s - %s" % (self.chapter, self.title)


# class CourseReview(models.Model):
#     """课程评价"""
#     enrolled_course = models.OneToOneField("EnrolledCourse")
#     about_teacher = models.FloatField(default=0, verbose_name="讲师讲解是否清晰")
#     about_video = models.FloatField(default=0, verbose_name="内容实用")
#     about_course = models.FloatField(default=0, verbose_name="课程内容通俗易懂")
#     review = models.TextField(max_length=1024, verbose_name="评价")
#     disagree_number = models.IntegerField(default=0, verbose_name="踩")
#     agree_number = models.IntegerField(default=0, verbose_name="赞同数")
#     tags = models.ManyToManyField("Tags", blank=True, verbose_name="标签")
#     date = models.DateTimeField(auto_now_add=True, verbose_name="评价日期")
#     is_recommend = models.BooleanField("热评推荐", default=False)
#     hide = models.BooleanField("不在前端页面显示此条评价", default=False)
#
#     def __str__(self):
#         return "%s-%s" % (self.enrolled_course.course, self.review)
#
#     class Meta:
#         verbose_name_plural = "13. 课程评价（购买课程后才能评价）"
#
#
# class DegreeCourseReview(models.Model):
#     """学位课程评价
#     为了以后可以定制单独的评价内容，所以不与普通课程的评价混在一起，单独建表
#     """
#     enrolled_course = models.ForeignKey("EnrolledDegreeCourse")
#     course = models.ForeignKey("Course", verbose_name="评价学位模块", blank=True, null=True,
#                                help_text="不填写即代表评价整个学位课程", limit_choices_to={'course_type': 2})
#     about_teacher = models.FloatField(default=0, verbose_name="讲师讲解是否清晰")
#     about_video = models.FloatField(default=0, verbose_name="视频质量")
#     about_course = models.FloatField(default=0, verbose_name="课程")
#     review = models.TextField(max_length=1024, verbose_name="评价")
#     disagree_number = models.IntegerField(default=0, verbose_name="踩")
#     agree_number = models.IntegerField(default=0, verbose_name="赞同数")
#     tags = models.ManyToManyField("Tags", blank=True, verbose_name="标签")
#     date = models.DateTimeField(auto_now_add=True, verbose_name="评价日期")
#     is_recommend = models.BooleanField("热评推荐", default=False)
#     hide = models.BooleanField("不在前端页面显示此条评价", default=False)
#
#     def __str__(self):
#         return "%s-%s" % (self.enrolled_course, self.review)
#
#     class Meta:
#         verbose_name_plural = "14. 学位课评价（购买课程后才能评价）"


class PricePolicy(models.Model):
    """价格与有课程效期表"""
    content_type = models.ForeignKey(ContentType)  # 关联course or degree_course
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

    # course = models.ForeignKey("Course")
    valid_period_choices = ((1, '1天'), (3, '3天'),
                            (7, '1周'), (14, '2周'),
                            (30, '1个月'),
                            (60, '2个月'),
                            (90, '3个月'),
                            (180, '6个月'), (210, '12个月'),
                            (540, '18个月'), (720, '24个月'),
                            )
    valid_period = models.SmallIntegerField(choices=valid_period_choices)
    price = models.FloatField()

    class Meta:
        unique_together = ("content_type", 'object_id', "valid_period")
        verbose_name_plural = "15. 价格策略"

    def __str__(self):
        return "%s(%s)%s" % (self.content_object, self.get_valid_period_display(), self.price)

# a.查看所有学位课并打印学位课名称以及授课老师

 degree_list = DegreeCourse.objects.all().values('name', 'teachers__name')
        print("degree_list===>",degree_list)
        # 打印结果：
        # #degree_list===> <QuerySet [{'name': '外卖骑士', 'teachers__name': 'PY 鱼'}, {'name': '年薪100万', 'teachers__name': 'wusir'}]>

  query_set   = DegreeCourse.objects.all()
        for row in query_set:
            print(row.name,row.teachers.all())
        #结果：外卖骑士 <QuerySet [<Teacher: PY 鱼>]>

# b.查看所有学位课并打印学位课名称以及学位课的奖学金

  degree_list = DegreeCourse.objects.all()
        for row in degree_list:
            print(row.name)
            scholarships = row.scholarship_set.all()
            for item in scholarships:
                print('------>',item.time_percent,item.value)

输出结果：

外卖骑士
年薪100万
------> 99999 90

# d. 查看id=1的学位课对应的所有模块名称

obj = DegreeCourse.objects.get(id=1)
        course_list = obj.course_set.all()
        print(course_list)

输出结果：

<QuerySet [<Course: css初始(学位课程)>]>

  course_list = Course.objects.filter(degree_course_id=1)
        print(course_list)

输出结果：
<QuerySet [<Course: css初始(学位课程)>]>

#  e.获取id = 1的专题课，并打印：课程名、级别(中文)、why_study、what_to_study_brief、所有recommend_courses

# obj = Course.objects.get(id=1)
# print(obj.name)
# print(obj.brief)
# print(obj.get_level_display() )
# print(obj.coursedetail.hours )
# print(obj.coursedetail.why_study )
# print(obj.coursedetail.recommend_courses.all() )

结果：

<QuerySet [{'name': '数据库基本操作'}]>
中级
<QuerySet [{'coursedetail__why_study': '因为少不了外卖'}]>
<QuerySet [{'coursedetail__what_to_study_brief': '怎么闯红灯'}]>
<QuerySet [{'coursedetail__recommend_courses': 1}, {'coursedetail__recommend_courses': 2}]>

# f.获取id = 1的专题课，并打印该课程相关的所有常见问题

c_obj = Course.objects.filter(id=1).first()
        print(c_obj.asked_question.all().values('question'))

　　　　结果：<QuerySet [{'question': '数据库是什么？'}]>

        obj = Course.objects.get(id=1)
        ask_list = obj.asked_question.all()
        for item in ask_list:
            print(item.question,item.answer)

　　　　结果：

<QuerySet [{'question': '数据库是什么？'}]>
数据库是什么？ 数据库(Database)是按照数据结构来组织、存储和管理数据的仓库，它产生于距今六十多年前，随着信息技术和市场的发展，特别是二十世纪九十年代以后，数据管理不再仅仅是存储和管理数据，而转变成用户所

# g.获取id = 1的专题课，并打印该课程相关的课程大纲

       # obj = Course.objects.get(id=1)
        # outline_list = obj.coursedetail.courseoutline_set.all()
        # for item in outline_list:
        #     print(item.title,item.content)

# h.获取id = 1的专题课，并打印该课程相关的所有章节

  obj = Course.objects.get(id=1)
        chapter_list = obj.xxxxx.all() # 默认obj.表名_set.all()
        for item in chapter_list:
            print(item.name)

结果：

美丽俏佳人
长发和尚光头尼

# i.获取id = 1的专题课，并打印该课程相关的所有的价格策略

c_obj = Course.objects.filter(id=1).first()
        print(c_obj.price_policy.all())

结果：

<QuerySet [<PricePolicy: 数据库基本操作(付费)(6个月)666666.0>]>