CODE EXAMPLE FOR 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');
});