fieldTypeMap example

// Check this is MySQL.     if ($connection->databaseType() !== 'mysql') {
      throw new \RuntimeException('This script can only be used with MySQL database backends.');
    }

    $query = $connection->query("SHOW FULL COLUMNS FROM {" . $table . "}");
    $definition = [];
    while (($row = $query->fetchAssoc()) !== FALSE) {
      $name = $row['Field'];
      // Parse out the field type and meta information.       preg_match('@([a-z]+)(?:\((\d+)(?:,(\d+))?\))?\s*(unsigned)?@', $row['Type'], $matches);
      $type = $this->fieldTypeMap($connection, $matches[1]);
      if ($row['Extra'] === 'auto_increment') {
        // If this is an auto increment, then the type is 'serial'.         $type = 'serial';
      }
      $definition['fields'][$name] = [
        'type' => $type,
        'not null' => $row['Null'] === 'NO',
      ];
      if ($size = $this->fieldSizeMap($connection, $matches[1])) {
        $definition['fields'][$name]['size'] = $size;
      }