Python 如何更新炼金术关联表?
我有一个这样的模型:Python 如何更新炼金术关联表?,python,flask,sqlalchemy,flask-sqlalchemy,Python,Flask,Sqlalchemy,Flask Sqlalchemy,我有一个这样的模型: taught_courses = db.Table( 'taught_courses', db.Column('teacher_id', db.Integer(), db.ForeignKey('teacher.id')), db.Column('course_id', db.Integer(), db.ForeignKey('course.id')), ) class Teacher(db.Model): __tablename__ =
taught_courses = db.Table(
'taught_courses',
db.Column('teacher_id', db.Integer(), db.ForeignKey('teacher.id')),
db.Column('course_id', db.Integer(), db.ForeignKey('course.id')),
)
class Teacher(db.Model):
__tablename__ = 'teacher'
id = db.Column(db.Integer, primary_key=True)
taught_courses = db.relationship('Course', secondary=taught_courses, lazy='subquery',
backref=db.backref('courses', lazy=True))
# ...
# ...
class Course(db.Model):
__tablename__ = 'course'
id = db.Column(db.Integer, primary_key=True)
# ...
# ...
下面是我如何将数据插入数据库:
teacher = Teacher(
name=form.first_name.data,
email=form.email.data)
db.session.add(teacher)
taught_courses = ['Tahsin', 'Arabic Language'] # in the actual case I use this dynamically.
course_id = db.session.query(Course.id).filter(Course.name.in_(taught_courses)).all()
for data in course_id:
course = Course.query.filter_by(id=data).first()
course.courses.append(teacher)
db.session.add(course)
db.session.commit()
下面是它在数据库中的外观:
teacher = Teacher(
name=form.first_name.data,
email=form.email.data)
db.session.add(teacher)
taught_courses = ['Tahsin', 'Arabic Language'] # in the actual case I use this dynamically.
course_id = db.session.query(Course.id).filter(Course.name.in_(taught_courses)).all()
for data in course_id:
course = Course.query.filter_by(id=data).first()
course.courses.append(teacher)
db.session.add(course)
db.session.commit()
这是为了插入,现在我想使更新成为可更新的
在另一个例子中,我想让它看起来像这样,在这里我们可以轻松地更新角色
所以我的问题是,如何更新关联表中的记录?我通过想象下面的例子来解决这个问题 所以,在我的问题中,我用下面的一行来计算:
current_course_name_from_db = ['Tahsin', 'Arabic Language'] # in the actual case I use this dynamically.
want_to_edit_course_with = ['Tahsin'] # in the actual case I use this dynamically.
course_id_1 = db.session.query(Course.id).filter(Course.name.in_(current_course_name_from_db)).all()
course_id_2 = db.session.query(Course.id).filter(Course.name.in_(want_to_edit_course_with)).all()
for data in course_id_1:
course = Course.query.filter_by(id=data).first()
course.courses.remove(teacher)
db.session.commit()
for data in course_id_2:
course = Course.query.filter_by(id=data).first()
course.courses.append(teacher)
db.session.commit()
所以我要做的第一件事是,删除数据库上的所有进程,然后再次进行循环以附加新值。我认为在执行提交之前需要添加对象。如果你想添加,你会得到一个序列化错误。有什么想法吗?