Find rows using foreign key in TypeORM - postgresql

Question

I have an OneToMany relation from User to Message.
When I insert register a user with a message, it adds the user to the User table, and the message to the Message table with a userId pointing to the user's id.
This is done automatically using the following setup.
User entity:
#Entity()
export class User {
#PrimaryGeneratedColumn()
id: number;
#Column()
name: string;
#Column()
email: string;
#JoinTable()
#OneToMany((type) => Message, (message) => message.user, {
cascade: true,
})
messages: Message[];
}
Message entity:
#Entity()
export class Message {
#PrimaryGeneratedColumn()
id: number;
#Column()
text: string;
#ManyToOne((type) => User, (user) => user.messages, { eager: true })
user: User[];
}
If I want to find all messages from a user via userId with:
const existing_msgs = await this.messageRepository.find({
where: { userId: user.id },
});
It tells me that it cannot find the userId column, which is understandable as I did not specifically include userId to the Message entity.
But how would we query it in this case?

Answer 1

As mentionned in This post, you have to add the decorator #JoinColumn after your manytoone. This will join the column and you will be able to perform the query you want with :
const existing_msgs = await this.messageRepository.find({
where: { user: { id: user.id }},
});
Note that this will work only on primary column like id.
And your message table will be :
#Entity()
export class Message {
#PrimaryGeneratedColumn()
id: number;
#Column()
text: string;
#ManyToOne((type) => User, (user) => user.messages, { eager: true })
#JoinColumn() // <-- Add this
user: User[];
}

Answer 2

I was able to do it with the following querybuilder.
const msg_arr = await this.userRepository
.createQueryBuilder('user')
.leftJoinAndSelect('user.messages', 'messages')
.where('user.id = :userId', { userId: user.id })
.andWhere('messages.text LIKE :text', { text: message })
.select('messages.text')
.execute();