sqlite self table FOREIGN KEY constraint failed with ON DELETE RESTRICT when drop()/sync({force:true})

Issue Description

I created a nested table that refers to itself. When it contains data, trying to execute the .drop() or .sync({force: true}) will trigger a constraint failure from sqlite.

What are you doing?

const Sequelize = require('sequelize');

const sequelize = new Sequelize({dialect: 'sqlite', storage: 'database.sqlite'});

class MyTable extends Sequelize.Model {
}

MyTable.init({
    parentId: {
        type: Sequelize.INTEGER,
        onDelete: 'RESTRICT',
        references: {
            model: MyTable,
            key: 'id'
        }
    }
}, { sequelize, modelName: 'Alarms'});

sequelize
    .sync({force: true})
    // root
    .then(_ => MyTable.build().save()
        // child
        .then(rootModel => MyTable.build({parentId: rootModel.id}).save()))

    // BOOM
    .then(_ => sequelize.sync({force: true}))
    .catch(error => console.error(error));

will output

CREATE TABLE "Alarms" (
	"id"	INTEGER PRIMARY KEY AUTOINCREMENT,
	"parentId"	INTEGER,
	"createdAt"	DATETIME NOT NULL,
	"updatedAt"	DATETIME NOT NULL,
	FOREIGN KEY("parentId") REFERENCES "Alarms"("id") ON DELETE RESTRICT
);

INSERT INTO "Alarms" (id, parentId, createdAt, updatedAt) VALUES(1, NULL, datetime('now'), datetime('now'));
INSERT INTO "Alarms" (id, parentId, createdAt, updatedAt) VALUES(2, 1, datetime('now'), datetime('now'));

What do you expect to happen?

Since I’m deleting the whole table, FK to the same table shouldn’t trigger this FK constraint.

Note: I don’t have a SQLite background, only a MSSQL/MYSQL. So this behavior is strange to me.

I did look into DROP TABLE documentation and they indeed talk about this behavior.

If foreign key constraints are enabled, a DROP TABLE command performs an implicit DELETE FROM command before removing the table from the database schema. […] An implicit DELETE FROM does cause any configured foreign key actions to take place.

I could see why this ticket could be closed as won’t do.

Environment

• Sequelize version: 5.21.1
• Node.js version: 10.13.0
• Operating System: Win64

Issue Template Checklist

How does this problem relate to dialects?

• I think this problem happens regardless of the dialect.
• I think this problem happens only for the following dialect(s): sqlite
• I don’t know, I was using PUT-YOUR-DIALECT-HERE, with connector library version XXX and database version XXX

Would you be willing to resolve this issue by submitting a Pull Request?

• Yes, I have the time and I know how to start.
• Yes, I have the time but I don’t know how to start, I would need guidance.
• No, I don’t have the time, although I believe I could do it if I had the time…
• No, I don’t have the time and I wouldn’t even know how to start.

[romannep]

For some cases could help turning off foreign key constrait

await sequelize.query('PRAGMA foreign_keys = false;');
sequelize.sync({...});
await sequelize.query('PRAGMA foreign_keys = true;');

[Suisse00]

I’m new to both SQLite and sequelize so I can’t suggest the best approach.

I did Google a little bit before submitting my suggestions and they did make no sense… SQLite doesn’t support to drop a column or FK… oh… crap…

So the only suggestion that left on my list is: Parse the FK constraint and delete rows ourselves in the right order. To this suggestion, I added the note (before googling): “at this point, it should probably be a user addon in a different NPM or the user should switch to ON DELETE CASCADE”

So I totally agree with you about the feature label! (if you still go ahead, and if there is nobody that already did this somewhere).

After thinking about it my recommendation would be: Close the issue. I should have know SQLite limit.