Flask数据库关系
Posted tmdhhl
tags:
篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了Flask数据库关系相关的知识,希望对你有一定的参考价值。
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:root@localhost/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))
以上是关于Flask数据库关系的主要内容,如果未能解决你的问题,请参考以下文章
Flask-SQLAlchemy 配置,处理对象-关系,一对多,多对多
Flask 学习-77.Flask-SQLAlchemy 一对一关系增删改查
Flask:05-一首歌的时间掌握flask数据模型(01)