class Role(db.Model):

    __tablename__='roles'

    id = db.Column(db.Integer,primary_key=True)

    name = db.Column(db.String(64),unique=True)

    users = db.relationship('User',backref='role')

    def __repr__(self):

        return '<Role %r>'% self.name

class User(db.Model):

    __tablename__ = 'users'

    id = db.Column(db.Integer, primary_key=True)

    username = db.Column(db.String(64), unique=True,index=True)

    role_id=db.Column(db.Integer,db.ForeignKey('role.id'))

    def __repr__(self):

        return '<User %r>' % self.username

设置SQLALCHEMY_TRACK_MODIFICATIONS 为True或False

报错：FSADeprecationWarning：

需要：提示给的839行，在前面几行的位置有这样的setdefault，

把None改为True;：

@app.route('/', methods=['get', 'post'])

def index1():

    #name = None

    form = NameForm()

    if form.validate_on_submit():

        user = User.query.filter_by(username=form.name.data).first()

        if user is None:

            user = User(username=form.name.data)

            db.session.add(user)

            session['known']=False

        else:

            session['known'] = True

        session['name']=form.name.data

        form.name.data=''

        return redirect(url_for('index1'))

    return render_template('index.html', name=session.get('name'), form=form, known=session.get('known',False))

# 集成python shell

def make_shell_context():

    return dict(app=app, db=db, User=User, Role=Role)

manager.add_command("shell", Shell(make_context=make_shell_context))

# 数据库迁移

migrate = Migrate(app,db)

manager.add_command('db',MigrateCommand)


# init命令创建迁移仓库
python flask_blog.py db init

# 创建迁移脚本
python flask_blog.py db migrate -m 'initial migration'

# 更新数据库

python flask_blog.py db upgrade