PHP

laravel migration remove constraint

// There are two ways to handle this:

// 1.	You can simply pass the column name wrapped in an array
//		and let laravel sort out the rest:
Schema::table('users', function (Blueprint $table) {
  $table->dropUnique(['email']);
  // $table->dropIndex(['email']); --> this pattern also works for other constraints/indexes like this
});

// 2.	You can remember the way laravel formats index names ([TABLE_NAME]_[COLUMN_NAME]_unique),
// 		and pass that as a string:
Schema::table('users', function (Blueprint $table) {
	$table->dropUnique('users_email_unique');
});

remove foreign key constraint laravel

Schema::table('table_name', function (Blueprint $table) {
    $table->dropForeign(['foreign_key']);
    $table->dropColumn('column_key');
});

PS: usually foreign_key = column_key

ex: 

Schema::table('despatch_discrepancies', function (Blueprint $table) {
    $table->dropForeign(['pick_detail_id']);
    $table->dropColumn('pick_detail_id');
});

laravel remove foreign key

$table->dropForeign('posts_user_id_foreign');

laravel migration drop foreign keys

$table->dropIndex(['state']); // Drops index 'geo_state_index'

laravel migration drop foreign keys

$table->dropPrimary('users_id_primary');