sqlalchemy.exc.IntegrityError：(sqlite3.IntegrityError) NOT NULL约束失败
sqlalchemy.exc.IntegrityError：(sqlite3.IntegrityError) NOT NULL约束失败
提问于 2021-01-25 01:50:16
我重新开始学习编程，然后我遇到了问题。我正在使用flask wtffroms，只想创建一个删除路由，每次我尝试删除我的帖子时，我都会收到这个错误
sqlalchemy.exc.IntegrityError: (sqlite3.IntegrityError) NOT NULL constraint failed: prekes_nuotraukos.preke_id
[SQL: UPDATE prekes_nuotraukos SET preke_id=? WHERE prekes_nuotraukos.id = ?]
[parameters: ((None, 20), (None, 21), (None, 22), (None, 23))]
(Background on this error at: http://sqlalche.me/e/13/gkpj)我认为问题是我对两个sqlalchemy表使用了一个wtfform变量，但它找不到prekes_nuotraukos.id，因为它在不同的表中，或者我遗漏了什么。这是我的model.db
class Preke(db.Model):
id = db.Column(db.Integer, primary_key=True)
pavadinimas = db.Column(db.String(30), nullable=False)
apibudinimas = db.Column(db.String(80), nullable=False)
creation_time = db.Column(db.DateTime, default=datetime.utcnow)
user_id = db.Column(db.Integer, db.ForeignKey("user.id"), nullable=False)
items = db.relationship("PrekesNuotraukos", backref="PrekesFT", lazy=True, uselist=True)
def __repr__(self):
return f"Post('{self.pavadinimas}', '{self.apibudinimas}', {self.creation_time})"
class PrekesNuotraukos(db.Model):
id = db.Column(db.Integer, primary_key=True)
prekes_nuotraukos = db.Column(db.String(20), nullable=False)
creation_time = db.Column(db.DateTime, default=datetime.utcnow)
preke_id = db.Column(db.Integer, db.ForeignKey("preke.id"), nullable=False)
def __repr__(self):
return f"Post('{self.creation_time}, {self.prekes_nuotraukos})"和前端部分的代码
<button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
<form action="{{url_for('delete_Preke', p_id=preke.id)}}" method="post">
<input class="btn btn-danger" type="submit" value="Delete">
</form>路由代码：
@app.route("/app_main_page/preke/<int:p_id>/delete", methods=["POST"])
@login_required
def delete_Preke(p_id):
preke = Preke.query.get_or_404(p_id)
if preke.author != current_user:
abort(403)
db.session.delete(preke)
db.session.commit()
flash("Jusu preke buvo sekmingai istrinta", "success")
return redirect(url_for(visos_prekes))回答 1
Stack Overflow用户
回答已采纳
发布于 2021-01-25 03:07:30
这个示例代码(纯SQLAlchemy，恐怕不是Flask-SQLAlchemy，但它们非常相似)展示了添加delete级联如何消除删除时的错误。
import sqlalchemy as sa
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import orm
Base = declarative_base()
class Preke(Base):
__tablename__ = 'preke'
id = sa.Column(sa.Integer, primary_key=True)
pavadinimas = sa.Column(sa.String(30), nullable=False)
# If we remove the "cascade='...'" from the next line, we get the error.
items = sa.orm.relationship("PrekesNuotraukos", backref="PrekesFT", lazy=True, uselist=True, cascade='all, delete-orphan')
class PrekesNuotraukos(Base):
__tablename__ = 'preke_nuotraukos'
id = sa.Column(sa.Integer, primary_key=True)
preke_id = sa.Column(sa.Integer, sa.ForeignKey("preke.id"), nullable=False)
engine = sa.create_engine('sqlite://', echo=True)
Base.metadata.create_all(engine)
Session = orm.sessionmaker(engine)
session = Session()
p = Preke(pavadinimas='A')
session.add(p)
pk1 = PrekesNuotraukos(PrekesFT=p)
pk2 = PrekesNuotraukos(PrekesFT=p)
session.add_all([pk1, pk2])
session.commit()
session.close()
session = Session()
p = session.query(Preke).first()
session.delete(p)
session.commit()
session.close()页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/65874020
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