数据库迁移完全版

1.0 主文件models

from exts import db


class User(db.Model):
    __tablename__ = 'user'

    id = db.Column(db.Integer, primary_key=True,autoincrement=True)
    username = db.Column(db.String(50))
    email = db.Column(db.String(50))

#建立多对多的关系需要建立中间表格
article_tag_table = db.Table(
    #表格名字
    'article_tag',
    #前面是关联的外键取名，后面是关联的id
    db.Column('article_id', db.Integer, db.ForeignKey('article1.id')),
    db.Column('tag_id', db.Integer, db.ForeignKey('tag.id'))
)

class Alticle(db.Model):
    __tablename__ = 'article1'

    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    title = db.Column(db.String(50))
    context = db.Column(db.String(50))
    uid = db.Column(db.Integer, db.ForeignKey('user.id'))

    auth = db.relationship('User', backref='articles')
    tags = db.relationship('Tag', secondary=article_tag_table, backref='tags')

class Tag(db.Model):
    __tablename__ = 'tag'

    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    name = db.Column(db.String(50))

3.0 建立中间文件exts

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

4.0 配置文件config

HOSTNAME = '127.0.0.1'

USERNAME = 'root'

PASSWORD = 'root'

PORT = '3306'

DATABASE = 'loft'

DB_URL = 'mysql+pymysql://{}:{}@{}:{}/{}'.format(USERNAME, PASSWORD, HOSTNAME, PORT, DATABASE)

SQLALCHEMY_DATABASE_URI = DB_URL
SQLALCHEMY_TRACK_MODIFICATIONS = False

5.0 操作三部曲

1. flask db init 初始画迁移文件夹
2. flask db migrate 把当前模型添加进迁移文件中
3. flask db upgrade 最后把迁移文件中对应的数据库操作，真正映射到数据库中