The query() method on a database object sends SQL to the database:

  $result = $db->query(sql);

A SQL statement that doesn’t query the database (e.g., INSERT , UPDATE , DELETE ) returns the DB_OK constant to indicate success. SQL that performs a query (e.g., SELECT ) returns an object that you can use to access the results.

You can check for success with DB::isError() :

  $q = $db->query($sql);
  if (DB::iserror($q)) {
    die($q->getMessage());
  }

Fetching Results from a Query

PEAR DB provides two methods for fetching data from a query result object. One returns an array corresponding to the next row, and the other stores the row array into a variable passed as a parameter.

Returning the row

The fetchRow() method on a query result returns an array of the next row of results:

  $row = $result->fetchRow([ mode ]);

This returns either an array of data, NULL if there is no more data (or none to begin with—an empty result), or DB_ERROR if an error occurred. The mode  parameter con trols the format of the array returned, which is discussed later.

This common idiom uses the fetchRow() method to process a result, one row at a time, as follows:

  while ($row = $result->fetchRow()) {
    if (DB::isError($row)) {
      die($row->getMessage());
    }
    // do something with the row
  }

Storing the row

The fetchInto() method not only gets the next row, but also stores it into the array variable passed as a parameter:

  $success = $result->fetchInto(array, [mode]);

Like fetchRow() , fetchInto() returns NULL if there is no more data, or DB_ERROR if an error occurs.

The idiom to process all results looks like this with fetchInto() :

  while ($success = $result->fetchInto($row)) {
    if (DB::isError($success)) {
      die($success->getMessage());
    }
    // do something with the row
  }