TypeORM PostgreSQL #ManyToOne save violates not-null constraint - postgresql

Question

I have a basic nestjs app with 3 entities :
document: DocumentEntity has pages: PageEntity[] as #OneToMany relation
page: PageEntity has words: WordEntity[]as #OneToMany relation + #ManyToOne document
word: WordEntity has a #ManyToOne page: PageEntity
This is quite straightforward and the first part of those relations works as expected :
I can save new pages doing so :
async createPage(documentId: number, url: string) {
const document = await this.documentRepository.findOne({ id: documentId });
if (document) {
const pageEntity = new PageEntity();
pageEntity.imgUrl = url;
pageEntity.document = document;
await this.pageRepository.save(pageEntity);
}
}
but when I try to apply the same logic to the words/page relation, it fails. I m not sure why this behaves differently
async postWord(pageId: number, word: { text: string }) {
const page = await this.pageRepository.findOne({ id: pageId });
if (page) {
const wordEntity = new WordEntity();
wordEntity.text = word.text;
wordEntity.page = page;
await this.wordRepository.save(wordEntity);
}
}
Error Message :
[ExceptionsHandler] null value in column "pageId" of relation "word_entity" violates not-null constraint +107723ms
QueryFailedError: null value in column "pageId" of relation "word_entity" violates not-null constraint
here are the entities declarations :
// document.entity.ts
#Entity()
class DocumentEntity {
#PrimaryGeneratedColumn()
public id?: number;
#Column()
public name: string;
#Column()
public locale: string;
#Column()
public pdfUrl: string;
#Column()
public folderPath: string;
#OneToMany(() => PageEntity, (page) => page.document, {
primary: true,
eager: true,
cascade: true,
})
public pages?: PageEntity[];
}
export default DocumentEntity;
// page.entity.ts
#Entity()
class PageEntity {
#PrimaryGeneratedColumn()
public id?: number;
#Column({ nullable: true })
public pageNumber?: number;
#Column({ nullable: true })
public text?: string;
#Column()
public imgUrl: string;
#OneToMany(() => WordEntity, (word) => word.page, {
eager: true,
onDelete: 'CASCADE',
primary: true,
})
words?: WordEntity[];
#ManyToOne(() => DocumentEntity, {
primary: true,
onDelete: 'CASCADE',
})
#JoinColumn()
public document: DocumentEntity;
}
export default PageEntity;
// word.entity.ts
#Entity()
class WordEntity {
#PrimaryGeneratedColumn()
public id?: number;
#ManyToOne(() => PageEntity, {
nullable: true,
primary: true,
onDelete: 'CASCADE',
})
#JoinColumn()
public page!: PageEntity;
#Column()
public text: string;
#Column({ type: 'decimal', nullable: true })
public confidence?: number;
}

Answer 1

Try this:
#Entity()
class WordEntity {
.....
#ManyToOne(() => PageEntity, {
nullable: true,
primary: true,
onDelete: 'CASCADE',
})
#JoinColumn({
name: 'pageId',
referencedColumnName: 'id',
})
page?: PageEntity;
#Column({ nullable: true })
pageId?: number
.....
}
async postWord(pageId: number, word: { text: string }) {
const wordEntity = new WordEntity();
wordEntity.text = word.text;
// check if the pageId exists, maybe inside Dto with a decorator
wordEntity.pageId = pageId;
await this.wordRepository.save(wordEntity);
}

Answer 2

You need to remove the primary: true from your #ManyToOne relation because a primary relation cannot be set as NULL