function DB_mysql::nextId in Flickr API 5

Returns the next free id in a sequence

DB_mysql::createSequence(), DB_mysql::dropSequence()

Parameters

string $seq_name name of the sequence:

boolean $ondemand when true, the seqence is automatically: created if it does not exist

Return value

int the next id number in the sequence. A DB_Error object on failure.

Overrides DB_common::nextId

See also

DB_common::nextID(), DB_common::getSequenceName(),

File

phpFlickr/PEAR/DB/mysql.php, line 580

Class

DB_mysql

The methods PEAR DB uses to interact with PHP's mysql extension for interacting with MySQL databases

Code

function nextId($seq_name, $ondemand = true) {
  $seqname = $this
    ->getSequenceName($seq_name);
  do {
    $repeat = 0;
    $this
      ->pushErrorHandling(PEAR_ERROR_RETURN);
    $result = $this
      ->query("UPDATE {$seqname} " . 'SET id=LAST_INSERT_ID(id+1)');
    $this
      ->popErrorHandling();
    if ($result === DB_OK) {

      // COMMON CASE
      $id = @mysql_insert_id($this->connection);
      if ($id != 0) {
        return $id;
      }

      // EMPTY SEQ TABLE
      // Sequence table must be empty for some reason, so fill
      // it and return 1 and obtain a user-level lock
      $result = $this
        ->getOne("SELECT GET_LOCK('{$seqname}_lock',10)");
      if (DB::isError($result)) {
        return $this
          ->raiseError($result);
      }
      if ($result == 0) {

        // Failed to get the lock
        return $this
          ->mysqlRaiseError(DB_ERROR_NOT_LOCKED);
      }

      // add the default value
      $result = $this
        ->query("REPLACE INTO {$seqname} (id) VALUES (0)");
      if (DB::isError($result)) {
        return $this
          ->raiseError($result);
      }

      // Release the lock
      $result = $this
        ->getOne('SELECT RELEASE_LOCK(' . "'{$seqname}_lock')");
      if (DB::isError($result)) {
        return $this
          ->raiseError($result);
      }

      // We know what the result will be, so no need to try again
      return 1;
    }
    elseif ($ondemand && DB::isError($result) && $result
      ->getCode() == DB_ERROR_NOSUCHTABLE) {

      // ONDEMAND TABLE CREATION
      $result = $this
        ->createSequence($seq_name);
      if (DB::isError($result)) {
        return $this
          ->raiseError($result);
      }
      else {
        $repeat = 1;
      }
    }
    elseif (DB::isError($result) && $result
      ->getCode() == DB_ERROR_ALREADY_EXISTS) {

      // BACKWARDS COMPAT
      // see _BCsequence() comment
      $result = $this
        ->_BCsequence($seqname);
      if (DB::isError($result)) {
        return $this
          ->raiseError($result);
      }
      $repeat = 1;
    }
  } while ($repeat);
  return $this
    ->raiseError($result);
}