Creating a TypeORM blog with PostgreSQL-like constraints

Question

Creating a TypeORM blog with PostgreSQL-like constraints

For my upcoming blog project, I am implementing a feature where users can like comments or posts using TypeORM with PostgreSQL. Below is the entity structure for likes:

@Entity()
@Unique(["user", "post", "comment"])
export default class Like {
  @PrimaryGeneratedColumn()
  id: number;

  // @Column()
  // likeCount: number;

  @ManyToOne(() => User, (user) => user.likes, { nullable: false })
  user: User;

  @ManyToOne(() => Post, (post) => post.likes)
  post: Post;

  @ManyToOne(() => Comment, (comment) => comment.likes)
  comment: Comment;

I am facing an issue where I need to prevent a user from liking a comment/post more than once. The unique constraints in the code above are not achieving this. Should I consider creating separate tables for liking a post and liking a comment? Also, how can I track the total number of likes for each comment/post?

The current unique constraint setup is ineffective and needs an alternative approach.

typescript postgresql typeorm

Answer 1

Answer №1

To ensure that a user can like multiple posts or comments, you can implement a unique constraint on either the user_id and comment_id columns, or the user_id and post_id columns. This approach will enable users to engage with various posts and comments without restrictions. Additionally, by utilizing foreign keys to establish connections between likes and posts/comments, you can guarantee the existence of relevant data in the database.

Answer 2

To ensure that a user can like multiple posts or comments, you can implement a unique constraint on either the user_id and comment_id columns, or the user_id and post_id columns. This approach will enable users to engage with various posts and comments without restrictions. Additionally, by utilizing foreign keys to establish connections between likes and posts/comments, you can guarantee the existence of relevant data in the database.

Answer 3

Answer №2

Include columns userId, postId, commentId and create a unique index for them.

Example below:

@Entity()
@Unique(["userId", "postId", "commentId"])
export default class Like {
  @PrimaryGeneratedColumn()
  id: number;

  // @Column()
  // likeCount: number;

  @Column()
  userId: number;

  @Column()
  postId: number;

  @Column()
  commentId: number;

  @ManyToOne(() => User, (user) => user.likes, { nullable: false })
  user: User;

  @ManyToOne(() => Post, (post) => post.likes)
  post: Post;

  @ManyToOne(() => Comment, (comment) => comment.likes)
  comment: Comment;

This ensures that one User can only like one Comment per Post.

Answer 4

Include columns userId, postId, commentId and create a unique index for them.

Example below:

@Entity()
@Unique(["userId", "postId", "commentId"])
export default class Like {
  @PrimaryGeneratedColumn()
  id: number;

  // @Column()
  // likeCount: number;

  @Column()
  userId: number;

  @Column()
  postId: number;

  @Column()
  commentId: number;

  @ManyToOne(() => User, (user) => user.likes, { nullable: false })
  user: User;

  @ManyToOne(() => Post, (post) => post.likes)
  post: Post;

  @ManyToOne(() => Comment, (comment) => comment.likes)
  comment: Comment;

This ensures that one User can only like one Comment per Post.

Creating a TypeORM blog with PostgreSQL-like constraints

Answer №1

Answer №2

Similar questions

What is the best approach to create a regex pattern that will identify variables enclosed in brackets across single and multiple lines?

Injecting a useFactory provider in Angular is a common practice

Angular - Dividing Functionality into Multiple Modules

Having trouble setting the default value of a select element with 'selected' in Angular's bootstrap?

Sharing markdown content between two Vue.js components

How to enhance an input field: incorporating unique buttons within

Ensuring the proper export of global.d.ts in an npm package

The router smoothly transitions to a new URL without requiring a change in the

The Angular BehaviorSubject observable is returning a null value

Form with checkboxes in a Next.js and Typescript application

Exploring the intricacies of pattern matching with JavaScript visualization

Fastify fails to register middleware when using the decorate method

Challenge: Visual Studio 2015 MVC6 and Angular 2 compilation issue - Promise name not found

What is the proper way to structure a React component class without any props?

Unable to send back transaction response from callback to the user

Create a system for detecting changes in simple input elements and triggering a function to update the final result

Deactivate user input depending on a certain requirement

I am experiencing issues with the customsort function when trying to sort a column of

The template displays an <object Object>, yet the observable async pipe functions without any errors

TypeScript was looking for 'never' but found an intersection instead