1
我想在Django的unique_together
替代烧瓶,似乎UniqueConstraint
是我正在寻找,但不适合我。为什么UniqueConstraint不起作用在flask_sqlalchemy
这里是例子:
import os
from flask import Flask
from flask_script import Manager, Shell
from flask_sqlalchemy import SQLAlchemy
basedir = os.path.abspath(os.path.dirname(__file__))
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] =\
'sqlite:///' + os.path.join(basedir, 'data.sqlite')
app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
manager = Manager(app)
db = SQLAlchemy(app)
class User(db.Model):
__tablename__ = 'users'
__table_args__ = tuple(db.UniqueConstraint('name', 'address'))
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(64), nullable=False)
address = db.Column(db.String(64), nullable=False)
def __repr__(self):
return '<User (%s, %s)>' % (self.name, self.address)
def make_shell_context():
return dict(app=app, db=db, user=User)
manager.add_command("shell", Shell(make_context=make_shell_context))
if __name__ == '__main__':
manager.run()
测试:
$ python test.py shell
In [1]: db.create_all()
In [2]: u1=user(name='a', address='x'); u2=user(name='a', address='x');
db.session.add(u1); db.session.add(u2); db.session.commit()
In [3]: user.query.all()
Out[3]: [<User (a, x)>, <User (a, x)>]
我也试图与:
class User(db.Model):
__tablename__ = 'users'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(64), nullable=False)
address = db.Column(db.String(64), nullable=False)
db.UniqueConstraint('name', 'address')
也不行,这有什么错呢?