assotiating two tables in sequelize - mysql

Question

Im having problems associating 2 models. I will try to describe the problem as detailed as possible and hope you can help me.
I have 2 Models: Zone and PLZ (both are also tables in database-mysql).
There can be One Zone having many PLZs and one PLZ can belong to One zone.
On saving a zone with its PLZs I have a table called "zone_plz" with only two columns: zone_id and plz_id. Both have foreign keys to Zone.id and PLZ.id
Zone Model:
const Sequelize = require('sequelize');
const sequelize = require('../util/database');
const PLZ = require('../models/PLZ');
const zone_plz = require('../models/relations/zone_plzs');
const Zone = sequelize.define('zone', {
name: {
type: Sequelize.STRING,
allowNull: false
},
color: {
type: Sequelize.STRING,
allowNull: false
}
}, {
timestamps: true
});
module.exports = Zone;
PLZ model:
const Sequelize = require('sequelize');
const sequelize = require('../util/database');
const Zone = require('../models/Zone');
const zone_plz = require('../models/relations/zone_plzs');
const PLZ = sequelize.define('plz', {
plz: {
type: Sequelize.INTEGER,
allowNull: false
},
city: {
type: Sequelize.STRING,
allowNull: false
},
district: {
type: Sequelize.STRING
}
});
module.exports = PLZ;
and this is the zone_plz model:
const Sequelize = require('sequelize');
const sequelize = require('../../util/database');
const PLZ = require('../../models/PLZ');
const Zone = require('../../models/Zone');
const zone_plz = sequelize.define('zone_plz', {
zone_id: {
type: Sequelize.INTEGER,
allowNull: false,
references: {
model: Zone,
key: 'id',
}
},
plz_id: {
type: Sequelize.INTEGER,
allowNull: false,
references: {
model: PLZ,
key: 'id',
}
}
}, {
timestamps: true
});
module.exports = zone_plz;
and this is how I query it:
router.get('/', function (req, res, next) {
zone_plz.findAll({
include: [{
model: PLZ,
as: 'plz'
},
{
model: Zone,
as: 'zone'
}]
}).then((result) => {
res.send({status: true, data: result})
}).catch(function (err) {
next(err)
})
});
As you can see i want to return a zone with all the belonging plzs to the user.
Im new to sequelize and Im also not sure if this is the right approach. I get the error: plz is not associated to zone_plz!
Can anyone help me?

Answer 1

You created references, not associations. Please, first of all, read the differences: Sequelize model references vs associations
then create associations between plz & zone like:
plz.belongsToMany(zone, {through: 'zone_plz'});
zone.belongsToMany(plz, {through: 'zone_plz'});