How to correctly associate tables in sequelize? - mysql

Question

I am trying to add associations to my defined tables and i am not sure if i have done it correctly. Basically i have a MySQL database that i want to re-create in sequelize as a second database.
MySQL tables:
CREATE TABLE IF NOT EXISTS account(
accountId INTEGER PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(50) NOT NULL,
password CHAR(60) NOT NULL,
CONSTRAINT usernameUnique UNIQUE (username)
);
CREATE TABLE IF NOT EXISTS thread(
threadId INTEGER PRIMARY KEY AUTO_INCREMENT,
threadName VARCHAR(50) NOT NULL,
threadOfAccount INTEGER NULL,
FOREIGN KEY (threadOfAccount) REFERENCES account(accountId),
CONSTRAINT threadNameUnique UNIQUE (threadName)
);
CREATE TABLE IF NOT EXISTS post(
postId INTEGER PRIMARY KEY AUTO_INCREMENT,
postTitle VARCHAR(50) NOT NULL,
postContent TEXT NOT NULL,
postOnThread INTEGER NOT NULL,
postOfAccount INTEGER NOT NULL,
FOREIGN KEY (postOnThread) REFERENCES thread(threadId),
FOREIGN KEY (postOfAccount) REFERENCES account(accountId),
CONSTRAINT postTitleUnique UNIQUE (postTitle)
);
I have defined the tables identically in sequelize.
The associations added for the moment:
db.thread.associate = (models) => {
this.thread.belongsTo(models.account, {
foreignKey: 'threadOfAccount'
})
}
db.thread.associate = (models) => {
this.thread.hasMany(models.post)
}
db.post.associate = (models) => {
this.post.belongsTo(models.thread, {
foreignKey: 'postOnThread'
})
}
db.post.associate = (models) => {
this.post.belongsTo(models.account, {
foreignKey: 'postOfAccount'
})
}
When i make a db call conatining a LEFT JOIN using sequelize like below:
module.exports = function({ SQLiteDb }){
return {
getAllPosts: function(threadId, callback) {
SQLiteDb.post.findAll({
include:[{
model: SQLiteDb.thread, as: 'thread',
where: { postOnThread: threadId },
required: false,
}],
raw: true
})
.then(posts => callback([], posts))
.catch(error => console.log(error, " ERRPR")
}
}
}
I receive this error:
EagerLoadingError [SequelizeEagerLoadingError]: thread is not associated to post!

Answer 1

post.belongsTo(models.thread, {
foreignKey: 'postOnThread',
as: 'thread',
});
post.belongsTo(models.account, {
foreignKey: 'postOfAccount',
as: 'account',
});
thread.belongsTo(models.account, {
foreignKey: 'threadOfAccount',
as: 'account',
});
thread.hasMany(models.post, {
foreignKey: 'postOnThread',
as: 'posts',
});
Test
const posts = await db.post.findAll({ include: ['account', 'thread'] });
console.log(JSON.parse(JSON.stringify(posts)));
const threads = await db.thread.findAll({ include: ['account', 'posts'] });
console.log(JSON.parse(JSON.stringify(threads)));
const accounts = await db.account.findAll({ include: ['account', 'posts'] });
console.log(JSON.parse(JSON.stringify(accounts)));
We need call after associate definition
db.account.associate(db);
db.post.associate(db);
db.thread.associate(db);