Issue description

TypeORM drops and creates indexes and foreign keys when migrating

Expected Behavior

I expect to see only changes in my entities.

Actual Behavior

Unnecessary queries like:

await queryRunner.query(ALTER TABLE `meeting_to_user` DROP FOREIGN KEY `FK_67fd4bcf288e6f67be1680f1080`); await queryRunner.query(ALTER TABLE `meeting_to_user` DROP FOREIGN KEY `FK_891897f387d5a605577427893be`); await queryRunner.query(ALTER TABLE `message_to_user` DROP FOREIGN KEY `FK_956ca24187965ed5ad5c36e1b49`); await queryRunner.query(ALTER TABLE `message_to_user` DROP FOREIGN KEY `FK_a422a0468e284bf6effb37960e0`); await queryRunner.query(ALTER TABLE `meeting_to_user` ADD CONSTRAINT `FK_67fd4bcf288e6f67be1680f1080` FOREIGN KEY (`usersId`) REFERENCES `users`(`id`) ON DELETE NO ACTION ON UPDATE NO ACTION); await queryRunner.query(ALTER TABLE `meeting_to_user` ADD CONSTRAINT `FK_891897f387d5a605577427893be` FOREIGN KEY (`meetingId`) REFERENCES `appointments`(`id`) ON DELETE NO ACTION ON UPDATE NO ACTION); await queryRunner.query(ALTER TABLE `message_to_user` ADD CONSTRAINT `FK_a422a0468e284bf6effb37960e0` FOREIGN KEY (`usersId`) REFERENCES `users`(`id`) ON DELETE NO ACTION ON UPDATE NO ACTION); await queryRunner.query(ALTER TABLE `message_to_user` ADD CONSTRAINT `FK_956ca24187965ed5ad5c36e1b49` FOREIGN KEY (`messageId`) REFERENCES `message`(`id`) ON DELETE NO ACTION ON UPDATE NO ACTION);

Steps to reproduce

Run migration

My Environment

| TypeORM version | 0.2.45 |

Additional Context

I can see people have already experienced this, but I can see no fix!
I saw that maybe the MariaDB driver was causing this, but I'm using the MySQL one.

Relevant Database Driver(s)

• aurora-mysql

  aurora-postgres

  better-sqlite3

  cockroachdb

  cordova

  expo

  mongodb

  mysql

  nativescript

  oracle

  postgres

  react-native

  sap

  spanner

  sqlite

  sqlite-abstract

  sqljs

  sqlserver
  To pick up a draggable item, press the space bar. While dragging, use the arrow keys to move the item. Press space again to drop the item in its new position, or press escape to cancel.

Are you willing to resolve this issue by submitting a Pull Request?

Yes, I have the time, and I know how to start.