how to make relationship between 2 tables using Node.js Express.js and Sequelize ORM

Question

Hi guys I'm in process of developing a web application using angular and node.js in the backend part, I used express.js and Sequelize ORM to make the server and the database but while I'm creating the tables I got some problem which is how to how to make a relationship between 2 tables Can you help me guys.! and thanks a lot.

Answer 1

Sequelize supports the standard associations betwen tables: One-To-One, One-To-Many and Many-To-Many.

To do this, Sequelize provides four types of associations that should be combined to create them:

• HasOne association
• BelongsTo association
• HasMany association
• BelongsToMany association

If you want more in detail info watchout sequelize docu: https://sequelize.org/master/manual/assocs.html

Answer 2

For a one-one relationships you define the two tables and then define the relationship

db.Table2.Table1 = db.Table2.belongsTo(db.Table1, {
    foreignKey: {
        name: “sharedId"
    }
});
db.Table1.Table2 = db.Table1.hasOne(db.Table2, {
    foreignKey: {
        name: "sharedId"
    }
});

For one-many relationships, you would change hasOne to hasMany or belongsTo to belongsToMany.