onupdate = "CASCADE"は何もしません

Question

onupdate="CASCADE"を使用しようとしましたが、カスケードは適用されません。 LeadとLeadStatusモデルとExemple、Lead.status_idに必要なカスケード：

# -*- coding: utf-8 -*- 
from flask import Flask 
from flask_sqlalchemy import SQLAlchemy 

app = Flask(__name__) 
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' 
app.config['DEBUG'] = True 
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False 
app.config['SQLALCHEMY_ECHO'] = False 
db = SQLAlchemy(app) 

class Lead(db.Model): 
    __tablename__ = 'lead' 

    id = db.Column(db.Integer(), primary_key=True) 
    name = db.Column(db.String(1024), nullable=False, server_default='') 
    status_id = db.Column(db.String(16), db.ForeignKey('lead_status.id', onupdate='CASCADE')) 
    status = db.relationship('LeadStatus', back_populates='leads') 


class LeadStatus(db.Model): 
    __tablename__ = 'lead_status' 

    id = db.Column(db.String(16), primary_key=True) 
    leads = db.relationship('Lead', back_populates='status') 


def print_trace(lead_status, lead): 
    print('DEBUG: status.id is {0}'.format(lead_status.id)) 
    print('DEBUG: {0}.status_id is {1}'.format(lead.name, lead.status_id)) 


if __name__ == '__main__': 
    db.create_all() 

    lead_status = LeadStatus(id='new') 
    lead = Lead(name='Foo', status=lead_status) 

    db.session.add(lead_status) 
    db.session.add(lead) 
    db.session.commit() 

    # debug 
    print_trace(lead_status, lead) 

    lead_status = db.session.query(LeadStatus).filter(LeadStatus.id == 'new').one() 
    lead = db.session.query(Lead).filter(Lead.name == 'Foo').one() 

    lead_status.id = 'new_renamed' 
    # db.session.delete(lead_status) 
    db.session.commit() 

    # debug 
    print_trace(lead_status, lead) 

    # lead_status = db.session.query(LeadStatus).filter(LeadStatus.id == 'new_renamed').one() 
    lead = db.session.query(Lead).filter(Lead.name == 'Foo').one() 

    # debug 
    print_trace(lead_status, lead) 

コードプロデュース：onupdate="CASCADE"作品を作る方法

DEBUG: status.id is new 
DEBUG: Foo.status_id is new 
DEBUG: status.id is new_renamed 
DEBUG: Foo.status_id is new 
DEBUG: status.id is new_renamed 
DEBUG: Foo.status_id is new 

？

Answer 1

デフォルトではSQLiteはキーの使用を無効にします。https://www.sqlite.org/foreignkeys.html#fk_enableを参照してください。あなたがそれらを活性化する必要があります。

db.session.execute('PRAGMA foreign_keys = ON') 

コードは現在生産：

DEBUG: status.id is new 
DEBUG: Foo.status_id is new 
DEBUG: status.id is new_renamed 
DEBUG: Foo.status_id is new_renamed 
DEBUG: status.id is new_renamed 
DEBUG: Foo.status_id is new_renamed