Sequelize Composite Foreign Key

Question

I have a database with the following tables:

CREATE TABLE IF NOT EXISTS `app_user` (
  `user_id` INT NOT NULL,
  `user_name` VARCHAR(45) NOT NULL,
  PRIMARY KEY (`user_id`))
ENGINE = InnoDB;

CREATE TABLE IF NOT EXISTS `user_folder` (
  `user_id` INT NOT NULL,
  `document_id` INT NOT NULL,
  PRIMARY KEY (`user_id`, `document_id`),
  CONSTRAINT `fk_user_document_user`
    FOREIGN KEY (`user_id`)
    REFERENCES `zinc`.`app_user` (`user_id`)
    ON DELETE CASCADE
    ON UPDATE CASCADE)
ENGINE = InnoDB;

CREATE TABLE IF NOT EXISTS `folder_content` (
  `user_id` INT NOT NULL,
  `document_id` INT NOT NULL,
  `content_id` INT NOT NULL,
  PRIMARY KEY (`user_id`, `document_id`, `content_id`),
  CONSTRAINT `fk_folder_content_folder`
    FOREIGN KEY (`user_id` , `document_id`)
    REFERENCES `zinc`.`user_folder` (`user_id` , `document_id`)
    ON DELETE CASCADE
    ON UPDATE CASCADE)
ENGINE = InnoDB;

I need to create a Sequelize model to represent it. The only problem I have is with the relation folder_content and user_folder because of the composite key.

How can I create this sequelize model?

This is what I have so far:

var AppUser = sequelize.define('app_user', 
{userId: {type: Sequelize.INTEGER, primaryKey: true, field: 'user_id'}, ... } );

var UserFolder = sequelize.define('user_folder', 
{userId: {type: Sequelize.INTEGER, primaryKey: true, field: 'user_id'}, 
documentId: {type: Sequelize.INTEGER, primaryKey: true, field: 'document_id'}... });

var FolderContent = sequelize.define('folder_content', {
userId: {type: Sequelize.INTEGER, primaryKey: true, field: 'user_id'}, 
documentId: {type: Sequelize.INTEGER, primaryKey: true, field: 'document_id'}, 
contentId: {type: Sequelize.INTEGER, primaryKey: true, field: 'content_id'}... });


UserFolder.hasMany(FolderContent);
FolderContent.belongsTo(UserFolder, {foreingKey: !! });// <- PROBLEM

Unfortunately this is not possbile yet. See github.com/sequelize/sequelize/issues/311 — Jan Aagaard Meier

Faris Faris · Accepted Answer · 2018-11-30T22:14:36

Now Sequelize doesn't support composite foreign keys. This creates several problems.

When Sequelize creates a table, the table definition does not have a composite FK.
To solve this problem I use the afterSync hook on the model and a function that adds a FK to the table if it does not exist. Example code.
When I use the findAll method with include such model, I use the include[].on option of the findAll method. Or if you don't use as many joins as I do, you can use scope when creating an association (see).

Sequelize Composite Foreign Key

2 Answers