protected function applyEquality($comparison, $query, $field, $input)
	{
		// Make SQL safe values
		$safe_field = $this->makeSafeField($field);
		$safe_input = $input  == '' ?
			'NULL' : DB::connection()->getPdo()->quote($input);

		// Different engines have different APIs
		switch(DB::getDriverName())
		{
			case 'mysql': return $this->applyMysqlEquality(
					$comparison, $query, $safe_field, $safe_input);
			case 'sqlite': return $this->applySqliteEquality(
					$comparison, $query, $safe_field, $safe_input);
            case 'sqlsrv': return $this->applySqlServerEquality(
					$comparison, $query, $safe_field, $safe_input);
        }
	}