code: public static function statement(Database $database, array $schema, string $modelName, string $tableName, string $fieldName)
      {
          $fieldDefinition = $schema[$modelName]['fields'][$fieldName];
          $fieldRealName = null;
          if (isset($fieldDefinition['name']) === true) {
              $fieldRealName = $fieldDefinition['name'];
          } else {
              $fieldRealName = Helper::codifyName($modelName) . '_' . Helper::codifyName($fieldName);
          }
          $sql = 'ALTER TABLE ' . $tableName . ' DROP COLUMN ' . $fieldRealName;
          $statement = $database->getMasterLink()->prepare($sql);
          return $statement;
      }
docs: Prepare and return according PDO statement.
  
  @param  Database                $database        database
  @param  array                   $schema          schema definition
  @param  string                  $modelName       model name
  @param  string                  $tableName       table name
  @param  string                  $fieldName       field name
  @return \PDOStatement           $statement       prepared query