Python构建学生信息管理系统：完成了项目初始化，结构，和一个hellowd的路由 结合博客学习使用

from app import db class Student(db.Model): __tablename__ = 'Students' StudentID = db.Column(db.Integer, primary_key=True) FirstName = db.Column(db.String(50), nullable=False) LastName = db.Column(db.String(50), nullable=False) ClassID = db.Column(db.Integer, db.ForeignKey('Classes.ClassID')) BirthDate = db.Column(db.Date, nullable=False) Email = db.Column(db.String(100), nullable=False) class_student = db.relationship('Class', backref='students', lazy=True) grades = db.relationship('Grade', backref='student', lazy=True) class Teacher(db.Model): __tablename__ = 'Teachers' TeacherID = db.Column(db.Integer, primary_key=True) FirstName = db.Column(db.String(50), nullable=False) LastName = db.Column(db.String(50), nullable=False) Email = db.Column(db.String(100), nullable=False) courses = db.relationship('Course', backref='teacher', lazy=True) class Course(db.Model): __tablename__ = 'Courses' CourseID = db.Column(db.Integer, primary_key=True) CourseName = db.Column(db.String(100), nullable=False) TeacherID = db.Column(db.Integer, db.ForeignKey('Teachers.TeacherID')) Description = db.Column(db.Text) grades = db.relationship('Grade', backref='course', lazy=True) class Grade(db.Model): __tablename__ = 'Grades' GradeID = db.Column(db.Integer, primary_key=True) StudentID = db.Column(db.Integer, db.ForeignKey('Students.StudentID')) CourseID = db.Column(db.Integer, db.ForeignKey('Courses.CourseID')) Score = db.Column(db.Float(5, 2), check_constraint="Score >= 0 AND Score <= 100") GradeDate = db.Column(db.Date) class Class(db.Model): __tablename__ = 'Classes' ClassID = db.Column(db.Integer, primary_key=True) ClassName = db.Column(db.String(100), nullable=False) Description = db.Column(db.Text)