Laravel migrations nice way of disabling foreign key checks
I had a similar task at hand when Lumen / Laravel started using Passport and I had to ditch the previous oauth server implementation from lucadegasperi/oauth2-server-laravel.
I finally managed to get things going by creating 2 migrations, where the first one clears foreign keys and the second one actually deletes the tables.
I had to use dates before the migrations of Laravel's Passport (2016-06-01) so they will be executed before those.
2016_05_31_000000_clear_old_oauth_relations.php
//...class ClearOldOauthRelations extends Migration{ public function up() { Schema::disableForeignKeyConstraints(); // drop foreign keys Schema::table('oauth_access_tokens', function (BluePrint $table) { $table->dropForeign('oauth_access_tokens_session_id_foreign'); }); //... Schema::enableForeignKeyConstraints(); } //...}
And in the second file2016_05_31_000001_clear_old_oauth.php
//...public function up(){ Schema::disableForeignKeyConstraints(); Schema::drop('oauth_access_tokens'); //... Schema::enableForeignKeyConstraints();}//...
I got this done by extracting the foreign key logic into a separate migration file. This helped me to:
- Disable the foreign key constraints.
- Securely drop the database, if it exists.
In code:
//file: 2017_06_19_230601_fk_postuser_table.phppublic function down(){ Schema::disableForeignKeyConstraints(); Schema::dropIfExists('post_user');}
Another important aspect to remember is to drop the foreignKey FIRST, then the column. Dropping the column first throws the error:
Cannot drop index 'tableName_columnName_foreign': needed in a foreign key constraint
The proper order matters:
public function down() { Schema::table('tableName', function (Blueprint $table) { $table->dropForeign(['columnName']); // fk first $table->dropColumn('columnName'); // then column }); }