only与defer

only括号内放字段查询结果是一个列表套一个个的数据对象
这些数据对象点括号内的字段属性不会再查询数据库 直接就是对象获取属性
也支持点击括号内没有的字段 但是每点击一次就会重新走一次数据库查询效率极低

defer与only是互为反操作
defer括号内放什么字段查询出来的对象就没有该字段属性
如果你要点击 每点击一次就要重新走一次数据
而你如果点击了非括号内的字段 就不会走数据库 仅仅是对象属性的操作

select_related与prefetch_related

select_related与prefetch_related
select_related括号内只能放外键字段 并且外键字段的类型只能是一对多或者一对一 不能是多对多
内部是自动连表操作会将括号内外键字段所关联的表与当前表自动拼接成一张表
然后将表中的数据一个个查询出来封装成一个个的对象
这样做的好处就在于跨表也不需要重复的走数据库了减轻数据库的压力
select_related括号内可以放多个外键字段都号隔开 会将多个外键字段关联的表与当前表全部拼成一张大表
耗时:数据库层面需要先连表

prefetch_related内部是子查询
会自动帮你按步骤查询多张表 然后将查询的结果封装到对象中
给用户的感觉好像还是连表操作
括号内支持传多个外键字段并且没有类型限制
特点:每放一个外键字段 就会多走一条sql语句多查询一张表
耗时：查询的次数长

两者之间的优缺点
结合实际情况表的大小
两张表都特别大的情况下连表操作可能耗时更多

MTV与MVC模型

MTV:

M:models 模型层

T:templates 模板层

V：views 视图层

MVC:

M:models 模型层

V:views 视图层

C：controllar路由匹配

choices参数

     如果存储的数字不在关系中又会怎么样
         能够正常存储
         也能够正常获取(数字)

    只要是choices字段类型 在获取值的时候 统一句式
    get_字段名_display()

from django.db import models
#
# # Create your models here.
class User(models.Model):
    username = models.CharField(max_length=64)
    password = models.IntegerField()
    gender_choices = (
        (1,'男'),
        (2,'女'),
        (3,'其他'),
    )
    gender = models.IntegerField(choices=gender_choices)
     # 该字段存数字
     """
     1.如果存储的数字在我们提前定义好的关系中会怎么样
     2.如果存储的数字不在关系中又会怎么样
         能够正常存储
         也能够正常获取(数字)
     """

# Create your tests here.
import os

if __name__ == "__main__":
    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "day55.settings")
    import django
    django.setup()
    from app01 import models

    user_obj = models.User.objects.get(pk=1)
    user_obj1 = models.User.objects.get(pk=4)
    # print(user_obj.gender)
    # print(user_obj1.gender)
    # print(user_obj.get_gender_display())
    print(user_obj1.get_gender_display())  # 没有对应关系 获取到的还是数字本身
    """
    只要是choices字段类型 在获取值的时候 统一句式
    get_字段名_display()
    """

实际例子：

from django.db import models

# Create your models here.
# rbac权限相关表格
class User(models.Model):
    name = models.CharField(max_length=32)
    pwd = models.CharField(max_length=32)
    roles = models.ManyToManyField(to='Role')

    def __str__(self):
        return self.name

class Role(models.Model):
    title = models.CharField(max_length=32)
    permissions = models.ManyToManyField(to='Permission')

    def __str__(self):
        return self.title

class Permission(models.Model):
    title = models.CharField(max_length=32)
    url = models.CharField(max_length=32)
    code = models.CharField(max_length=32,default='list')

    def __str__(self):
        return self.title


# CRM相关内部表
class School(models.Model):
    """
    校区表
    如：
        北京沙河校区
        上海校区

    """
    title = models.CharField(verbose_name='校区名称', max_length=32)

    def __str__(self):
        return self.title

class Course(models.Model):
    """
    课程表
    如：
        Linux基础
        Linux架构师
        Python自动化开发精英班
        Python自动化开发架构师班
        Python基础班
        go基础班
    """
    name = models.CharField(verbose_name='课程名称', max_length=32)

    def __str__(self):
        return self.name

class Department(models.Model):
    """
    部门表
    市场部     1000
    销售       1001

    """
    title = models.CharField(verbose_name='部门名称', max_length=16)
    code = models.IntegerField(verbose_name='部门编号', unique=True, null=False)

    def __str__(self):
        return self.title

class UserInfo(models.Model):
    """
    员工表
    """

    name = models.CharField(verbose_name='员工姓名', max_length=16)
    email = models.EmailField(verbose_name='邮箱', max_length=64)
    depart = models.ForeignKey(verbose_name='部门', to="Department",to_field="code")
    user=models.OneToOneField("User",default=1)
    def __str__(self):
        return self.name

class ClassList(models.Model):
    """
    班级表
    如：
        Python全栈  面授班  5期  10000  2017-11-11  2018-5-11
    """
    school = models.ForeignKey(verbose_name='校区', to='School')
    course = models.ForeignKey(verbose_name='课程名称', to='Course')
    semester = models.IntegerField(verbose_name="班级(期)")


    price = models.IntegerField(verbose_name="学费")
    start_date = models.DateField(verbose_name="开班日期")
    graduate_date = models.DateField(verbose_name="结业日期", null=True, blank=True)
    memo = models.CharField(verbose_name='说明', max_length=256, blank=True, null=True, )

    teachers = models.ManyToManyField(verbose_name='任课老师', to='UserInfo',limit_choices_to={'depart':1002})
    tutor = models.ForeignKey(verbose_name='班主任', to='UserInfo',related_name="class_list",limit_choices_to={'depart':1006})


    def __str__(self):
        return "{0}({1}期)".format(self.course.name, self.semester)


class Customer(models.Model):
    """
    客户表
    """
    qq = models.CharField(verbose_name='qq', max_length=64, unique=True, help_text='QQ号必须唯一')

    name = models.CharField(verbose_name='学生姓名', max_length=16)
    gender_choices = ((1, '男'), (2, '女'))
    gender = models.SmallIntegerField(verbose_name='性别', choices=gender_choices)

    education_choices = (
        (1, '重点大学'),
        (2, '普通本科'),
        (3, '独立院校'),
        (4, '民办本科'),
        (5, '大专'),
        (6, '民办专科'),
        (7, '高中'),
        (8, '其他')
    )
    education = models.IntegerField(verbose_name='学历', choices=education_choices, blank=True, null=True, )
    graduation_school = models.CharField(verbose_name='毕业学校', max_length=64, blank=True, null=True)
    major = models.CharField(verbose_name='所学专业', max_length=64, blank=True, null=True)

    experience_choices = [
        (1, '在校生'),
        (2, '应届毕业'),
        (3, '半年以内'),
        (4, '半年至一年'),
        (5, '一年至三年'),
        (6, '三年至五年'),
        (7, '五年以上'),
    ]
    experience = models.IntegerField(verbose_name='工作经验', blank=True, null=True, choices=experience_choices)
    work_status_choices = [
        (1, '在职'),
        (2, '无业')
    ]
    work_status = models.IntegerField(verbose_name="职业状态", choices=work_status_choices, default=1, blank=True,
                                      null=True)
    company = models.CharField(verbose_name="目前就职公司", max_length=64, blank=True, null=True)
    salary = models.CharField(verbose_name="当前薪资", max_length=64, blank=True, null=True)

    source_choices = [
        (1, "qq群"),
        (2, "内部转介绍"),
        (3, "官方网站"),
        (4, "百度推广"),
        (5, "360推广"),
        (6, "搜狗推广"),
        (7, "腾讯课堂"),
        (8, "广点通"),
        (9, "高校宣讲"),
        (10, "渠道代理"),
        (11, "51cto"),
        (12, "智汇推"),
        (13, "网盟"),
        (14, "DSP"),
        (15, "SEO"),
        (16, "其它"),
    ]
    source = models.SmallIntegerField('客户来源', choices=source_choices, default=1)
    referral_from = models.ForeignKey(
        'self',
        blank=True,
        null=True,
        verbose_name="转介绍自学员",
        help_text="若此客户是转介绍自内部学员,请在此处选择内部学员姓名",
        related_name="internal_referral"
    )
    course = models.ManyToManyField(verbose_name="咨询课程", to="Course")

    status_choices = [
        (1, "已报名"),
        (2, "未报名")
    ]
    status = models.IntegerField(
        verbose_name="状态",
        choices=status_choices,
        default=2,
        help_text=u"选择客户此时的状态"
    )

    consultant = models.ForeignKey(verbose_name="课程顾问", to='UserInfo', related_name='consultanter',limit_choices_to={'depart':1001})

    date = models.DateField(verbose_name="咨询日期", auto_now_add=True)
    recv_date = models.DateField(verbose_name="当前课程顾问的接单日期", null=True)
    last_consult_date = models.DateField(verbose_name="最后跟进日期", )

    def __str__(self):
        return self.name

class ConsultRecord(models.Model):
    """
    客户跟进记录
    """
    customer = models.ForeignKey(verbose_name="所咨询客户", to='Customer')
    consultant = models.ForeignKey(verbose_name="跟踪人", to='UserInfo',limit_choices_to={'depart':1001})
    date = models.DateField(verbose_name="跟进日期", auto_now_add=True)
    note = models.TextField(verbose_name="跟进内容...")

    def __str__(self):
        return self.customer.name + ":" + self.consultant.name

class Student(models.Model):
    """
    学生表（已报名）
    """
    customer = models.OneToOneField(verbose_name='客户信息', to='Customer')
    class_list = models.ManyToManyField(verbose_name="已报班级", to='ClassList', blank=True)

    emergency_contract = models.CharField(max_length=32, blank=True, null=True, verbose_name='紧急联系人')
    company = models.CharField(verbose_name='公司', max_length=128, blank=True, null=True)
    location = models.CharField(max_length=64, verbose_name='所在区域', blank=True, null=True)
    position = models.CharField(verbose_name='岗位', max_length=64, blank=True, null=True)
    salary = models.IntegerField(verbose_name='薪资', blank=True, null=True)
    welfare = models.CharField(verbose_name='福利', max_length=256, blank=True, null=True)
    date = models.DateField(verbose_name='入职时间', help_text='格式yyyy-mm-dd', blank=True, null=True)
    memo = models.CharField(verbose_name='备注', max_length=256, blank=True, null=True)

    def __str__(self):
        return self.customer.name

class ClassStudyRecord(models.Model):
    """
    上课记录表 （班级记录）
    """
    class_obj = models.ForeignKey(verbose_name="班级", to="ClassList")
    day_num = models.IntegerField(verbose_name="节次", help_text=u"此处填写第几节课或第几天课程...,必须为数字")
    teacher = models.ForeignKey(verbose_name="讲师", to='UserInfo',limit_choices_to={'depart':1002})
    date = models.DateField(verbose_name="上课日期", auto_now_add=True)

    course_title = models.CharField(verbose_name='本节课程标题', max_length=64, blank=True, null=True)
    course_memo = models.TextField(verbose_name='本节课程内容概要', blank=True, null=True)
    has_homework = models.BooleanField(default=True, verbose_name="本节有作业")
    homework_title = models.CharField(verbose_name='本节作业标题', max_length=64, blank=True, null=True)
    homework_memo = models.TextField(verbose_name='作业描述', max_length=500, blank=True, null=True)
    exam = models.TextField(verbose_name='踩分点', max_length=300, blank=True, null=True)

    def __str__(self):
        return "{0} day{1}".format(self.class_obj, self.day_num)

class StudentStudyRecord(models.Model):
    '''
    学生学习记录
    '''
    classstudyrecord = models.ForeignKey(verbose_name="第几天课程", to="ClassStudyRecord")
    student = models.ForeignKey(verbose_name="学员", to='Student')







    record_choices = (('checked', "已签到"),
                      ('vacate', "请假"),
                      ('late', "迟到"),
                      ('noshow', "缺勤"),
                      ('leave_early', "早退"),
                      )
    record = models.CharField("上课纪录", choices=record_choices, default="checked", max_length=64)
    score_choices = ((100, 'A+'),
                     (90, 'A'),
                     (85, 'B+'),
                     (80, 'B'),
                     (70, 'B-'),
                     (60, 'C+'),
                     (50, 'C'),
                     (40, 'C-'),
                     (0, ' D'),
                     (-1, 'N/A'),  # 通常情况下-1表示没有或者数据丢失
                     (-100, 'COPY'),
                     (-1000, 'FAIL'),
                     )
    score = models.IntegerField("本节成绩", choices=score_choices, default=-1)
    homework_note = models.CharField(verbose_name='作业评语', max_length=255, blank=True, null=True)
    note = models.CharField(verbose_name="备注", max_length=255, blank=True, null=True)

    homework = models.FileField(verbose_name='作业文件', blank=True, null=True, default=None)
    stu_memo = models.TextField(verbose_name='学员备注', blank=True, null=True)
    date = models.DateTimeField(verbose_name='提交作业日期', auto_now_add=True)

    def __str__(self):
        return "{0}-{1}".format(self.classstudyrecord, self.student)

day 55 ajax

only与defer

select_related与prefetch_related

MTV与MVC模型

MTV:

M:models 模型层

T:templates 模板层

V：views 视图层

MVC:

M:models 模型层

V:views 视图层

C：controllar路由匹配

choices参数

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