Has one association in Sequelize - node.js

Question

I have a User Model with a hasOne relation on Role Model
User.init({
id: {
type: DataTypes.INTEGER.UNSIGNED,
autoIncrement: true,
primaryKey: true
},
name: {
type: DataTypes.STRING,
allowNull: false
},
//email, password, and other fields, ...
roleId: {
type:DataTypes.INTEGER,
allowNull: false
}},
{
sequelize,
tableName: "Users"
});
User.hasOne(Role)
and a Role Model
Role.init({
id: {
type: DataTypes.INTEGER.UNSIGNED,
autoIncrement: true,
primaryKey: true
},
name: {
type: DataTypes.STRING,
allowNull: false
}},
{
sequelize,
tableName: "Roles"
});
When I try to create a new Role with
await Role.create(req.body)
And the request is
POST http://localhost:3000/api/role
Content-Type: application/json
Authorization: Bearer <token>
{
"name": "test role"
}
I get the error column "UserId" does not exist
And the log says is:
routine: 'errorMissingColumn',
sql: 'INSERT INTO "Roles" ("id","name") VALUES (DEFAULT,$1) RETURNING "id","name","UserId";',
parameters: [
'test role'
]
What did I do wrong here? My table only has roleId in the Users table, where did the UserId in Roles table come from?
Migrations
'use strict';
module.exports = {
up: (queryInterface, Sequelize) => {
return queryInterface.createTable('Roles', {
id: {
allowNull: false,
autoIncrement: true,
primaryKey: true,
type: Sequelize.INTEGER
},
name: {
type: Sequelize.STRING,
allowNull: false
}
});
},
down: (queryInterface, Sequelize) => {
return queryInterface.dropTable('Roles');
}
};
'use strict';
module.exports = {
up: (queryInterface, Sequelize) => {
return queryInterface.createTable('Users', {
id: {
allowNull: false,
autoIncrement: true,
primaryKey: true,
type: Sequelize.INTEGER
},
name: {
type: Sequelize.STRING
},
// other fields
roleId: {
type: Sequelize.INTEGER,
references: {
model: "Roles",
key: "id"
}
}
});
},
down: (queryInterface, Sequelize) => {
return queryInterface.dropTable('Users');
}
};
If I add Role.belongsTo(User) in the Role Model, I get the error:
models init error: TypeError: Cannot read property 'name' of undefined

Answer 1

For the role to be stored in the user table as your schema suggests: User.belongsTo(Role) will setup the mapping for you as RoleId.
The Model sets up the foreign key the opposite way to the migrations, so results in a missing UserID column.
The foreign keys don't need to be defined in the schema unless you want to customise the fields. The belongsTo/hasOne options are then defined on association call.
const { Sequelize, Model, DataTypes } = require('sequelize')
const sequelize = new Sequelize('sqlite::memory:')
class User extends Model {}
class Role extends Model {}
User.init({
id: {
type: DataTypes.INTEGER.UNSIGNED,
autoIncrement: true,
primaryKey: true
},
name: {
type: DataTypes.STRING,
allowNull: false
}},
{
sequelize,
tableName: "Users"
});
Role.init({
id: {
type: DataTypes.INTEGER.UNSIGNED,
autoIncrement: true,
primaryKey: true
},
name: {
type: DataTypes.STRING,
allowNull: false
}},
{
sequelize,
tableName: "Roles"
});
User.belongsTo(Role, { foreignKey: 'roleId' })
Then you can do things with the association
async function go(){
await sequelize.sync()
const role = await Role.create({ name: 'atester' })
const user = await User.create({ name: 'test' })
await user.setRole(role)
console.log("%j", await User.findAll({ include: Role }))
}
go().catch(console.error)
Results in a document like:
{
"id": 1,
"name": "test",
"createdAt": "2020-12-04T09:44:05.762Z",
"updatedAt": "2020-12-04T09:44:05.763Z",
"roleId": 1,
"Role": {
"id": 1,
"name": "atester",
"createdAt": "2020-12-04T09:44:05.758Z",
"updatedAt": "2020-12-04T09:44:05.758Z"
}
}
From there you can match your migration to the database.