I want to insert with mikro-orm, but it dont find my table :c (TableNotFoundException)

So

Console:

yarn dev
yarn run v1.22.10
$ nodemon dist/index.js
[nodemon] 2.0.7
[nodemon] to restart at any time, enter `rs`
[nodemon] watching path(s): *.*
[nodemon] watching extensions: js,mjs,json  
[nodemon] starting `node dist/index.js`     
[discovery] ORM entity discovery started, using ReflectMetadataProvider
[discovery] - processing entity Post
[discovery] - entity discovery finished, found 1 entities, took 21 ms
[info] MikroORM successfully connected to database postgres on postgresql://postgres:*****@127.0.0.1:5432
[query] begin
[query] insert into "post" ("created_at", "title", "updated_at") values ('2021-04-05T21:04:23.126Z', 'my first post', '2021-04-05T21:04:23.126Z') returning "_id" [took 12 ms]
[query] rollback
TableNotFoundException: insert into "post" ("created_at", "title", "updated_at") values ('2021-04-05T21:04:23.126Z', 'my first post', '2021-04-05T21:04:23.126Z') returning "_id" - relation "post" does not exist
    at PostgreSqlExceptionConverter.convertException (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\postgresql\PostgreSqlExceptionConverter.js:36:24)
    at PostgreSqlDriver.convertException (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\core\drivers\DatabaseDriver.js:194:54)
    at P:\.Projektek\lireddit-server\node_modules\@mikro-orm\core\drivers\DatabaseDriver.js:198:24
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
    at async PostgreSqlDriver.nativeInsert (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\knex\AbstractSqlDriver.js:150:21)
    at async ChangeSetPersister.persistNewEntity (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\core\unit-of-work\ChangeSetPersister.js:55:21)
    at async ChangeSetPersister.executeInserts (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\core\unit-of-work\ChangeSetPersister.js:24:13)
    at async UnitOfWork.commitCreateChangeSets (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\core\unit-of-work\UnitOfWork.js:496:9)
    at async UnitOfWork.persistToDatabase (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\core\unit-of-work\UnitOfWork.js:458:13)
    at async PostgreSqlConnection.transactional (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\knex\AbstractSqlConnection.js:53:25)
    at async UnitOfWork.commit (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\core\unit-of-work\UnitOfWork.js:183:17)
    at async SqlEntityManager.flush (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\core\EntityManager.js:486:9)
    at async SqlEntityManager.persistAndFlush (P:\.Projektek\lireddit-server\node_modules\@mikro-orm\core\EntityManager.js:438:9)

previous error: insert into "post" ("created_at", "title", "updated_at") values ('2021-04-05T21:04:23.126Z', 'my 
first post', '2021-04-05T21:04:23.126Z') returning "_id" - relation "post" does not exist
    at Parser.parseErrorMessage (P:\.Projektek\lireddit-server\node_modules\pg-protocol\dist\parser.js:278:15)   
    at Parser.handlePacket (P:\.Projektek\lireddit-server\node_modules\pg-protocol\dist\parser.js:126:29)        
    at Parser.parse (P:\.Projektek\lireddit-server\node_modules\pg-protocol\dist\parser.js:39:38)
    at Socket.<anonymous> (P:\.Projektek\lireddit-server\node_modules\pg-protocol\dist\index.js:10:42)
    at Socket.emit (events.js:315:20)
    at Socket.EventEmitter.emit (domain.js:467:12)
    at addChunk (internal/streams/readable.js:309:12)
    at readableAddChunk (internal/streams/readable.js:284:9)
    at Socket.Readable.push (internal/streams/readable.js:223:10)
    at TCP.onStreamRead (internal/stream_base_commons.js:188:23) {
  length: 166,
  severity: 'ERROR',
  code: '42P01',
  detail: undefined,
  hint: undefined,
  position: '13',
  internalPosition: undefined,
  internalQuery: undefined,
  where: undefined,
  schema: undefined,
  table: undefined,
  column: undefined,
  dataType: undefined,
  constraint: undefined,
  file: 'd:\\pginstaller_13.auto\\postgres.windows-x64\\src\\backend\\parser\\parse_relation.c',
  line: '1376',
  routine: 'parserOpenTable'
}

Index.ts:

import { MikroORM } from "@mikro-orm/core";
import { __prod__ } from "./constants";
import { Post } from "./entities/Post";
import mikroConfig from "./mikro-orm.config";

const main = async () => {
  const orm = await MikroORM.init(mikroConfig);
  await orm.getMigrator().up;
  const post = orm.em.create(Post, { title: "my first post" });
  await orm.em.persistAndFlush(post);
};

main().catch((err) => {
  console.error(err);
});

Post.ts:

import { Entity, PrimaryKey, Property } from "@mikro-orm/core";

@Entity()
export class Post {
  @PrimaryKey()
  _id!: number;

  @Property({ type: "date" })
  createdAt = new Date();

  @Property({ type: "date", onUpdate: () => new Date() })
  updatedAt = new Date();

  @Property({ type: "text" })
  title!: string;
}

mikro-orm.config.ts:

import { __prod__ } from "./constants";
import { Post } from "./entities/Post";
import { MikroORM } from "@mikro-orm/core";
import path from "path";

export default {
  migrations: {
    path: path.join(__dirname, "./migrations"),
    pattern: /^[\w-]+\d+\.[tj]s$/,
  },
  entities: [Post],
  dbName: "postgres",
  debug: !__prod__,
  type: "postgresql",
  password: "hellothere",
} as Parameters<typeof MikroORM.init>[0];

And the migration I created with npx mikro-orm migration:create:

import { Migration } from '@mikro-orm/migrations';

export class Migration20210405205411 extends Migration {

  async up(): Promise<void> {
    this.addSql('create table "post" ("_id" serial primary key, "created_at" timestamptz(0) not null, "updated_at" timestamptz(0) not null, "title" text not null);');
  }

}

After that im compiling it to js btw, but I guess the problem will be somewhere at my code or idk plz help me, I can give you more info just plz help, I've been trying to fix this bug for 5 hours :/

Btw Im doin Ben Awad's 14 hour fullstack tutorial if its matter.

I have had the same issue. This is what I did:

1. I deleted the migrations folder as well as the dist folder
2. I ran npx mikro-orm migration:create --initial

After that, I restarted yarn watch and yarn dev and it worked for me.

Notice the --initial flag. I would recommend to check the official documentation. The migrations table is used to keep track of already executed migrations. When you only run npx mikro-orm migration:create, the table will not be created and therefore MikroORM is unable to check if the migration for the Post entity has already been performed (which includes creating the respective table on the database).

Ben does not use the --initial flag in his tutorial, he might have already ran it prior to the tutorial.