如何在flask_sqlalchemy中向表中添加记录？

Question

我正在使用flask做一个项目，我选择Flask-sqlalchemy来存储数据。数据库存储在本地：

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///manage.db'

我定义了两个类：

class House(db.Model):
    __tablename__ = 'house'
    id: Mapped[int] = mapped_column(db.Integer, primary_key=True)
    block: Mapped[str] = mapped_column(db.String, nullable=False)
    number: Mapped[str] = mapped_column(db.String, nullable=False)
    area: Mapped[int] = mapped_column(db.Integer) 

class Residents(db.Model):
    __tablename__ = 'residents'
    r_id: Mapped[str] = mapped_column(db.String, primary_key=True) 
    r_name: Mapped[str] = mapped_column(db`your text`.String) 
    r_phone: Mapped[str] = mapped_column(db.String, nullable=False)
    r_work_place: Mapped[str] = mapped_column(db.String, nullable=False)

我定义了一个表，记录居民及其房屋：

tags = db.Table('tags',
db.Column('house_id',db.Integer, db.ForeignKey('house.id')),
db.Column('res_id',db.String, db.ForeignKey('residents.r_id'))
)

现在我想向表'tags'添加记录，该表定义为db.Table，如何实现这个过程？

Answer 1

如果您按照文档中所述为双向多对多关系添加映射，则可以像在列表中一样添加和删除对象。

from sqlalchemy.orm import (
    Mapped, 
    relationship
)
from typing import List

class House(db.Model):
    # ...

    residents: Mapped[List['Residents']] = relationship(
        secondary=tags, back_populates='houses'
    )

class Residents(db.Model):
    # ...

    houses: Mapped[List['House']] = relationship(
        secondary=tags, back_populates='residents'
    )

house = House(...)
db.session.add(house)
db.session.commit()

resident = Residents(...)
house.residents.append(resident)
db.session.commit()