class Course(Base):
__tablename__ = 'course'
lable = models.Column(models.String(32), unique=True)
teachers = models.relationship('Teachers', backref='to_course')
# 外表用这个字段，本表用backref
to_student = models.relationship(
'Student',
secondary=Stu_Cou, #指向多对多表
backref=models.backref('to_course_ya', lazy='dynamic'),
lazy='dynamic' #不加载数据
)
class Course(Base):
__tablebname__ = "course"
name = models.Column(models.String(32), unique=True)
description = models.Column(models.Text)
to_teacher = models.relationship("Teacher", backref="to_course_data")
to_student = models.relationship("Students",
secondary=Stu_Cou,
backref=models.backref("to_course",
lazy="dynamic"),
lazy="dynamic")
class Course(BaseModel):
__tablename__ = 'course'
lable = models.Column(models.String(32))
description = models.Column(models.Text)
to_teacher = models.relationship('Teacher', backref='to_course1')
to_student = models.relationship('Student',
secondary=Stu_Cou,
backref=models.backref('to_course',
lazy='dynamic'),
lazy='dynamic')
class Course(BaseModel): #课程表
__tablename = "course"
label = models.Column(models.String(32))
description = models.Column(models.Text)
#双向映射
to_teachers = models.relationship( #relationship关联关系relationship
'Teachers', #映射类的名称和类名一致#双向映射
backref='to_course')
#教师类映射到该表
#双向映射语法(一对多)：字段名=models.relationship(
#"映射的类名"，
#backref="本表名")
to_student = models.relationship(
"Students",
secondary=Stu_Cou, #多对多关系表
backref=models.backref("to_course", lazy="dynamic"),
lazy="dynamic")
class Course(BaseModel):
__tablename__ = 'course' # 课程表名
#id = models.Column(models.Integer, primary_key=True, autoincrement=True)
lable = models.Column(models.String(32))
description = models.Column(models.Text)
updatetime = models.Column(models.DateTime, default=datetime.timezone)
#反向映射字段,一对多关系查询
to_teacher = models.relationship(
'Teacher', #映射表
backref='to_course', #反向映射字段，通过该字段查询当表的内容
lazy='dynamic')
#多对多关系查询
to_students = models.relationship('Students',
secondary=Stu_Cou,
backref=models.backref("to_course",
lazy='dynamic'),
lazy='dynamic')
class Teacher(BaseModel):
__tablename__ = 'teacher'
#id = models.Column(models.Integer, primary_key=True, autoincrement=True)
name = models.Column(models.String(32)) # 老师姓名
age = models.Column(models.Integer) # 老师年龄
gender = models.Column(models.Integer) # 老师性别0男，1女，-1不知道
description = models.Column(models.Text) #老师简介信息
course_id = models.Column(models.Integer,
models.ForeignKey('course.id')) #专业与老师一对多关系
# 多对多关系查询
to_students = models.relationship('Students',
secondary=Stu_Tea,
backref=models.backref("to_teacher",
lazy='dynamic'),
lazy='dynamic')
# 与假条表是一对多的关系
to_ask = models.relationship('Ask', backref='to_teacher')
class Course(BaseModel): #课程
__tablename__ = "course"
label = models.Column(models.String(32))
description = models.Column(models.Text)
to_teacher = models.relationship(
"Teachers", #映射表
backref="to_course_data" #反向映射字段，映射表通过该字段可以查到当前表内容
)
to_student = models.relationship(
"Students",
secondary=Stu_Cou,
backref=models.backref("to_course", lazy="dynamic"),
lazy="dynamic",
# lazy 的参数
# select 访问该字段时候，加载所有的映射数据
# joined 对关联的两个表students和stu_cou进行join查询
# dynamic 不加载数据
)
class Course(BaseModel):
"""
课程表
"""
__tablename__ = 'course'
label = models.Column(models.String(32))
description = models.Column(models.Text)
#设置双向映射
to_teacher = models.relationship( #执行映射表的字段
'Teacher', #映射表，映射到谁
backref='to_course_data' #反向映射字段
)
#多对多
to_student = models.relationship(
'Students',
secondary=Stu_Cou,
backref=models.backref('to_course', lazy='dynamic'), #stu_cou course
lazy='dynamic', #stu_cou student
#select 访问该字段的时候加载所有映射数据
#joined 对关联的两个表student和teacher表进行join查询
#dynamic 不加载数据,为了防止数据多的时候查询卡
)