Dropping column with foreign key Laravel error: General error: 1025 Error on rename

Question

I've created a table using migration like this: ``` public function up() { Schema::create('despatch_discrepancies', function($table) { $table->increments('id')->unsigned(); $table->integer('pick_id')->unsigned(); $table->foreign('pick_id')->references('id')->on('picks'); $table->integer('pick_detail_id')->unsigned(); $table->foreign('pick_detail_id')->references('id')->on('pick_details'); $table->integer('original_qty')->unsigned(); $table->integer('shipped_qty')->unsigned(); }); } public function down() { Schema::drop('despatch_discrepancies'); } ``` I need to change this table and drop the foreign key reference & column `pick_detail_id` and add a new varchar column called `sku` after `pick_id` column. So, I've created another migration, which looks like this: ``` public function up() { Schema::table('despatch_discrepancies', function($table) { $table->dropForeign('pick_detail_id'); $table->dropColumn('pick_detail_id'); $table->string('sku', 20)->after('pick_id'); }); } public functi…

Accepted Answer

It turns out; when you create a foreign key like this: ``` $table->integer('pick_detail_id')->unsigned(); $table->foreign('pick_detail_id')->references('id')->on('pick_details'); ``` Laravel uniquely names the foreign key reference like this: ``` ___foreign despatch_discrepancies_pick_detail_id_foreign (in my case) ``` Therefore, when you want to drop a column with foreign key reference, you have to do it like this: ``` $table->dropForeign('despatch_discrepancies_pick_detail_id_foreign'); $table->dropColumn('pick_detail_id'); ``` Update: Laravel 4.2+ introduces a new naming convention: ``` __foreign ``` Update: Larave > 8.x introduces a new function ``` dropConstrainedForeignId('pick_detail_id'); ``` This will delete the column as well as the foreign key of the column

Dropping column with foreign key Laravel error: General error: 1025 Error on rename

Solution

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