sqlalchemy学习笔记

外键

class User(db.Model):
__tablename__ = 'users'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(20), nullable=False)

def __init__(self, name):
self.name = name

class Article(db.Model):
__tablename__ = 'articles'
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(50), nullable=False)
content = db.Column(db.Text, nullable=False)
author_id = db.Column(db.Integer, db.ForeignKey('users.id'))
author = db.relationship('User', backref=db.backref('articles'))

def __init__(self, title, content):
self.title = title
self.content = content

多对多

Article_tag = db.Table(
'article_tag',
db.Column('article_id', db.Integer, db.ForeignKey('articles.id'), primary_key=True),
db.Column('tag_id', db.Integer, db.ForeignKey('tags.id'), primary_key=True)
)

class Article(db.Model):
__tablename__ = 'articles'

id = db.Column(db.Integer, primary_key=True, autoincrement=True)
title = db.Column(db.String(20), nullable=False)
content = db.Column(db.Text, nullable=False)
tags = db.relationship(
'Tag',
secondary=Article_tag,
backref=db.backref('tags', lazy='dynamic'),  # 动态
lazy='dynamic'  # 动态
)

def __init__(self, title, content):
self.title = title
self.content = content

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

id = db.Column(db.Integer, primary_key=True, autoincrement=True)
name = db.Column(db.String(20), nullable=False)
articles = db.relationship(
'Article',
secondary=Article_tag,
backref=db.backref('articles', lazy='dynamic'),  # 动态
lazy='dynamic'  # 动态
)

def __init__(self, name):
self.name = name