Gorm Lost indexes on SQLite table rewrite when adding FK

Description

When adding FK to existing SQLite table, table is rewritten with FK added but existing indexes are not recreated after rewrite.

To reproduce:

(1) create table with index:

CREATE TABLE `items` (`id` integer NOT NULL, `name` varchar(100) NOT NULL,`user_id` integer,PRIMARY KEY (`id`))

CREATE INDEX `idx_items_name` ON `items`(`name`)

(2) add FK to existing table created in (1) with Migrator().CreateConstraint() :

# Adding FK from items table to users table with Migrator().CreateConstraint() makes GORM to recreate table with FK...

CREATE TABLE `items__temp` (`id` integer NOT NULL,`name` varchar(100) NOT NULL,`user_id` integer, PRIMARY KEY (`id`),CONSTRAINT `fk_users_items` FOREIGN KEY (`user_id`) REFERENCES `users`(`id`))

INSERT INTO `items__temp`(`id`,`name`,`user_id`) SELECT `id`,`name`,`user_id` FROM `items`

DROP TABLE `items`

ALTER TABLE `items__temp` RENAME TO `items`

# ...but existing indexes (like idx_items_name above) are not recreated in new table.

Comment From: github-actions[bot]

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Comment From: pboguslawski

No such problem with recreating existing FK when other FK is added to the same SQlite table; so rewriting SQlite table on adding FK preservers existing FK but not existing indexes.

Comment From: github-actions[bot]

Comment From: a631807682

If you are using AutoMigrate, you need to add tag gorm:"index" to ensure it will not lose.

Comment From: pboguslawski

If you are using AutoMigrate, you need to add tag gorm:"index" to ensure it will not lose.

Problem was noticed when adding FK with Migrator().CreateConstraint(). AutoMigrate was not checked.

Comment From: github-actions[bot]

Comment From: a631807682

Patch Constraint is not currently supported https://github.com/go-gorm/gorm/issues/5559#issuecomment-1200718658

Comment From: github-actions[bot]