SQLAlchemy：如何在不将其作为主键的情况下创建整数列auto_increment（和unique）？

I am using Flask extension for SQLAlchemy to define my database model. I want an id column to be int type and with auto_increment property but without making it a primary key. How do I achieve it?

我正在使用Flask扩展来为SQLAlchemy定义我的数据库模型。我想要一个id列是int类型和auto_increment属性，但没有使它成为主键。我该如何实现？

I tried this:

我试过这个：

from flask import Flask, jsonify
from flask.ext.sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:ajay@localhost/pydb'
app.config['SQLALCHEMY_ECHO'] = True
db = SQLAlchemy(app)

class Scenario(db.Model):
    scid = db.Column(db.Integer, nullable=False, unique=True, autoincrement=True)
    scenario_name = db.Column(db.String(100), primary_key=True)
    scenario_description = db.Column(db.String(200), nullable=False)
    image_id = db.Column(db.Integer, db.ForeignKey('images.id', onupdate='CASCADE', ondelete='CASCADE'))

    def __init__(self, scenario_name, scenario_description, image_id=None):
        self.scenario_name = scenario_name
        self.scenario_description = scenario_description
        self.image_id = image_id

    def __repr__(self):
        return '<Scenario %r, %r, %r>' % (self.scenario_name, self.scenario_description, self.image_id)

but this doesn't set the scid column as auto_increment.

但是这不会将scid列设置为auto_increment。

1 个解决方案

#1

You can add an AUTO_INCREMENT not primary key but you can't have two AUTO_INCREMENT fields

您可以添加AUTO_INCREMENT而不是主键，但不能有两个AUTO_INCREMENT字段

If you don't have AUTO_INCREMENT you can add an AUTO_INCREMENT and UNIQUE whith something like this:

如果你没有AUTO_INCREMENT，你可以添加一个AUTO_INCREMENT和UNIQUE，如下所示：

ALTER TABLE `items` ADD `AutoInc` INT NOT NULL AUTO_INCREMENT, ADD UNIQUE (`AutoInc`)

#1