Drizzle Team•13mo ago

Explaining the differences between .references() and relations function

Hi I'm a bit unclear in the example why the comments table in this example does not use the .references() function on the author id field. Is this because the .relations() method and relations({one}) are achieveing the same thing but two different approaches? https://orm.drizzle.team/docs/rqb#one-to-many

...
 
export const posts = pgTable('posts', {
    id: serial('id').primaryKey(),
    content: text('content'),
    authorId: integer('author_id'),
});
 
export const postsRelations = relations(posts, ({ one, many }) => ({
    author: one(users, {
        fields: [posts.authorId],
        references: [users.id],
    }),
    comments: many(comments)
}));
 
export const comments = pgTable('comments', {
    id: serial('id').primaryKey(),
    text: text('text'),
    authorId: integer('author_id'),
    postId: integer('post_id'),
});
 
export const commentsRelations = relations(comments, ({ one }) => ({
    post: one(posts, {
        fields: [comments.postId],
        references: [posts.id],
    }),
}));

...
 
export const posts = pgTable('posts', {
    id: serial('id').primaryKey(),
    content: text('content'),
    authorId: integer('author_id'),
});
 
export const postsRelations = relations(posts, ({ one, many }) => ({
    author: one(users, {
        fields: [posts.authorId],
        references: [users.id],
    }),
    comments: many(comments)
}));
 
export const comments = pgTable('comments', {
    id: serial('id').primaryKey(),
    text: text('text'),
    authorId: integer('author_id'),
    postId: integer('post_id'),
});
 
export const commentsRelations = relations(comments, ({ one }) => ({
    post: one(posts, {
        fields: [comments.postId],
        references: [posts.id],
    }),
}));

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3 Replies

Angelelz•13mo ago

Yes, the answer is a little further down in that link: https://orm.drizzle.team/docs/rqb#foreign-keys

Drizzle Queries - Drizzle ORM

Drizzle ORM is a lightweight and performant TypeScript ORM with developer experience in mind.

SamOP•13mo ago

Hi @Angelelz so to clarify .references() creates a foreign key constraint but relations does not? But they can also work fairly interchangably in databases that support foreign key contraints.

Angelelz•13mo ago

The answer to the first part of your question is yes. But defining relations won't create foreign key constrains in the database. This was done on purpose to support database provider like planetscale that don't support foreign keys

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Explaining the differences between .references() and relations function