sequelize cli creating a polymorphic one to many and many to many relation - polymorphic-associations

Question

I want to create a polymorphic relation like in the diagram using sequalize-cli es6 format.
I have created this model using sequelize-cli
npx sequelize-cli model:generate --name Post --attributes name:string
npx sequelize-cli model:generate --name Video --attributes title:string
npx sequelize-cli model:generate --name Comment --attributes comments:text,comments_id:integer,comments_type:string
It generate following files
Model files:
'use strict';
const {
Model
} = require('sequelize');
module.exports = (sequelize, DataTypes) => {
class Post extends Model {
/**
* Helper method for defining associations.
* This method is not a part of Sequelize lifecycle.
* The `models/index` file will call this method automatically.
*/
static associate(models) {
// define association here
}
}
Post.init({
name: DataTypes.STRING
}, {
sequelize,
modelName: 'Post',
});
return Post;
};
'use strict';
const {
Model
} = require('sequelize');
module.exports = (sequelize, DataTypes) => {
class Video extends Model {
/**
* Helper method for defining associations.
* This method is not a part of Sequelize lifecycle.
* The `models/index` file will call this method automatically.
*/
static associate(models) {
// define association here
}
}
Video.init({
title: DataTypes.STRING
}, {
sequelize,
modelName: 'Video',
});
return Video;
};
'use strict';
const {
Model
} = require('sequelize');
module.exports = (sequelize, DataTypes) => {
class Comment extends Model {
/**
* Helper method for defining associations.
* This method is not a part of Sequelize lifecycle.
* The `models/index` file will call this method automatically.
*/
static associate(models) {
// define association here
}
}
Comment.init({
comments: DataTypes.TEXT,
comments_id: DataTypes.INTEGER,
comments_type: DataTypes.STRING
}, {
sequelize,
modelName: 'Comment',
});
return Comment;
};
Migration files:
'use strict';
/** #type {import('sequelize-cli').Migration} */
module.exports = {
async up(queryInterface, Sequelize) {
await queryInterface.createTable('Posts', {
id: {
allowNull: false,
autoIncrement: true,
primaryKey: true,
type: Sequelize.INTEGER
},
name: {
type: Sequelize.STRING
},
createdAt: {
allowNull: false,
type: Sequelize.DATE
},
updatedAt: {
allowNull: false,
type: Sequelize.DATE
}
});
},
async down(queryInterface, Sequelize) {
await queryInterface.dropTable('Posts');
}
};
'use strict';
/** #type {import('sequelize-cli').Migration} */
module.exports = {
async up(queryInterface, Sequelize) {
await queryInterface.createTable('Videos', {
id: {
allowNull: false,
autoIncrement: true,
primaryKey: true,
type: Sequelize.INTEGER
},
title: {
type: Sequelize.STRING
},
createdAt: {
allowNull: false,
type: Sequelize.DATE
},
updatedAt: {
allowNull: false,
type: Sequelize.DATE
}
});
},
async down(queryInterface, Sequelize) {
await queryInterface.dropTable('Videos');
}
};
'use strict';
/** #type {import('sequelize-cli').Migration} */
module.exports = {
async up(queryInterface, Sequelize) {
await queryInterface.createTable('Comments', {
id: {
allowNull: false,
autoIncrement: true,
primaryKey: true,
type: Sequelize.INTEGER
},
comments: {
type: Sequelize.TEXT
},
comments_id: {
type: Sequelize.INTEGER
},
comments_type: {
type: Sequelize.STRING
},
createdAt: {
allowNull: false,
type: Sequelize.DATE
},
updatedAt: {
allowNull: false,
type: Sequelize.DATE
}
});
},
async down(queryInterface, Sequelize) {
await queryInterface.dropTable('Comments');
}
};
Can anyone explain to me how to modify this files to make relationship like in the diagram. I am new to sequalize-cli orm .. Thank you.
I am trying to build a website. Using sequalize orm I will make my work much easier..

Answer 1

I think the below documentation will help U
URL: https://sequelize.org/docs/v6/advanced-association-concepts/eager-loading/
Answer:
Posts.hasMany(Comments)
Comments.belongsTo(Posts)
Videos.hasMany(Comments)
Comments.belongsTo(Videos)