基础配置
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
db = SQLAlchemy(app)
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://root:[email protected]/flask'
一对多
class Singer(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(70), unique=True)
songs = db.relationship('Song', backref='singer')
class Song(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(70), unique=True)
singer_id = db.Column(db.Integer, db.ForeignKey('singer.id'))
多对一(不是必须时还是用与一对多吧)
比一对多的用法,会少一个从一里访问多的字段。
class Citizen(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(70), unique=True)
city_id = db.Column(db.Integer, db.ForeignKey('city.id'))
city = db.relationship('City')
class Country(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(79), unique=True)
capital = db.relationship('Capital', uselist=False)
一对一
class Country(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(79), unique=True)
capital = db.relationship('Capital', uselist=False)
class Capital(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(70), unique=True)
country_id = db.Column(db.Integer, db.ForeignKey('country.id'))
country = db.relationship('Country'
多对多
association_table = db.Table(
'association',
db.Column('student_id', db.Integer, db.ForeignKey('student.id')),
db.Column('teacher_id', db.Integer, db.ForeignKey('teacher.id'))
)
class Student(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(70), unique=True)
grade = db.Column(db.String(20))
teachers = db.relationship(
'Teacher', secondary=association_table, backref='students')
class Teacher(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(70), unique=True)
office = db.Column(db.String(20))
原文地址:https://www.cnblogs.com/tmdhhl/p/11408409.html
时间: 2024-10-07 10:27:40