How to query many-to-many relationship data in Sequelize - mysql

Question

I have got a many-to-many relationship between two models, users and groups.
I have two models which are specifying the belongsToMany with a foreignKey and through attribute.
Users model
'use strict';
module.exports = function(sequelize, DataTypes) {
var User = sequelize.define('User', {
firstName: DataTypes.STRING,
lastName: DataTypes.STRING,
email: DataTypes.STRING,
username: DataTypes.STRING,
facebookId: DataTypes.STRING,
password: DataTypes.STRING,
}, {
classMethods: {
associate: function(models) {
User.hasMany(models.Payment);
User.hasMany(models.Friend, {foreignKey: 'userIdLink1'});
User.belongsToMany(models.Group, { through: 'UsersGroups', foreignKey: 'facebookId' });
}
},
instanceMethods: {
toJSON: function () {
var values = Object.assign({}, this.get());
delete values.password;
return values;
}
}
});
return User;
};
groups model
'use strict';
module.exports = function(sequelize, DataTypes) {
var Group = sequelize.define('Group', {
name: DataTypes.STRING
}, {
classMethods: {
associate: function(models) {
// associations can be defined here
Group.belongsToMany(models.User, {through: 'UsersGroups', foreignKey: 'groupId'});
Group.hasMany(models.Payment)
}
},
instanceMethods: {
toJSON: function () {
var values = Object.assign({}, this.get());
delete values.password;
return values;
}
}
});
return Group;
};
which are being joined via a junction table UsersGroups
This works fine and I can create a new group and it links the user with it successfully but when I try fetch the data the SQL query is trying to find Groups based on User.id as opposed to User.facebookId like I specified in my model User.belongsToMany(models.Group, { through: 'UsersGroups', foreignKey: 'facebookId' });
I call the following code to fetch the data:
const options = {
where: {
facebookId: facebookId,
},
defaults: {
firstName: data.firstName,
lastName: data.lastName,
email: data.email,
facebookId: facebookId
},
include: [
{ model: db.Group }
]
}
db.User.findOrCreate(options)
.then((user) => {
res.send(user)
}, (err) => {
res.status(500).send(err)
})
and it returns a user but with an empty Groups array which is incorrect as there is definitely data there as I can create it fine and see it in the DB.
You can see the SQL query that is generated by Sequelize here:
SELECT `User`.*, `Groups`.`id` AS `Groups.id`, `Groups`.`name` AS `Groups.name`, `Groups`.`createdAt` AS `Groups.createdAt`, `Groups`.`updatedAt` AS `Groups.updatedAt`, `Groups.UsersGroups`.`createdAt` AS `Groups.UsersGroups.createdAt`, `Groups.UsersGroups`.`updatedAt` AS `Groups.UsersGroups.updatedAt`, `Groups.UsersGroups`.`facebookId` AS `Groups.UsersGroups.facebookId`, `Groups.UsersGroups`.`groupId` AS `Groups.UsersGroups.groupId`
FROM (
SELECT `User`.`id`, `User`.`firstName`, `User`.`lastName`, `User`.`email`, `User`.`username`, `User`.`facebookId`, `User`.`password`, `User`.`createdAt`, `User`.`updatedAt` FROM `Users` AS `User` WHERE `User`.`facebookId` = '1341052992643877' LIMIT 1) AS `User`
LEFT OUTER JOIN (`UsersGroups` AS `Groups.UsersGroups`
INNER JOIN `Groups` AS `Groups` ON `Groups`.`id` = `Groups.UsersGroups`.`groupId`
)
ON `User`.`id` = `Groups.UsersGroups`.`facebookId`;
Note the last line
ON `User`.`id` = `Groups.UsersGroups`.`facebookId`
needs to be
ON `User`.`facebookId` = `Groups.UsersGroups`.`facebookId`

Answer 1

Turns out I had to specify facebookId as a primary key in my user model
facebookId: {
type: DataTypes.STRING,
primaryKey: true,
},