-- DropForeignKey ALTER TABLE `Collection` DROP FOREIGN KEY `Collection_parentId_fkey`; -- DropForeignKey ALTER TABLE `Folder` DROP FOREIGN KEY `Folder_parentId_fkey`; -- AlterTable ALTER TABLE `Collection` MODIFY `parentId` INTEGER NULL; -- AlterTable ALTER TABLE `Folder` MODIFY `parentId` INTEGER NULL; -- AddForeignKey ALTER TABLE `Folder` ADD CONSTRAINT `Folder_parentId_fkey` FOREIGN KEY (`parentId`) REFERENCES `Folder`(`id`) ON DELETE SET NULL ON UPDATE CASCADE; -- AddForeignKey ALTER TABLE `Collection` ADD CONSTRAINT `Collection_parentId_fkey` FOREIGN KEY (`parentId`) REFERENCES `Folder`(`id`) ON DELETE SET NULL ON UPDATE CASCADE;