Flask 学习 四 数据库

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;：

视图函数中操作数据库

@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 

pip install flask-migrate

from flask_migrate import Migrate,MigrateCommand

# 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