Last updated: Fri, 20 Nov 2009

PDOStatement->getColumnMeta

(PHP 5 >= 5.1.0, PECL pdo >= 0.2.0)

PDOStatement->getColumnMeta — Returns metadata for a column in a result set

Descrierea

array PDOStatement::getColumnMeta ( int $column )

Avertizare

Această funcţie este EXPERIMENTALĂ. Comportamentul acestei funcţii, denumirea sa şi orice alte aspecte documentate în privinţa acestei funcţii pot să fie modificate fără preaviz într-o versiune viitoare a PHP. Utilizaţi această funcţie la propriul risc.

Retrieves the metadata for a 0-indexed column in a result set as an associative array.

Avertizare

Not all PDO drivers support PDOStatement::getColumnMeta().

Parametri

column: The 0-indexed column in the result set.

Valorile întroarse

Returns an associative array containing the following values representing the metadata for a single column:

**Column metadata**
Name	Value
native_type	The PHP native type used to represent the column value.
driver:decl_type	The SQL type used to represent the column value in the database. If the column in the result set is the result of a function, this value is not returned by PDOStatement::getColumnMeta().
flags	Any flags set for this column.
name	The name of this column as returned by the database.
table	The name of this column's table as returned by the database.
len	The length of this column. Normally -1 for types other than floating point decimals.
precision	The numeric precision of this column. Normally 0 for types other than floating point decimals.
pdo_type	The type of this column as represented by the PDO::PARAM_* constants.

Returns FALSE if the requested column does not exist in the result set, or if no result set exists.

Istoria schimbărilor

Versiunea	Descriere
5.2.3	table field

Exemple

Example #1 Retrieving column metadata

The following example shows the results of retrieving the metadata for a single column generated by a function (COUNT) in a PDO_SQLITE driver.


<?php
$select = $DB->query('SELECT COUNT(*) FROM fruit');
$meta = $select->getColumnMeta(0);
var_dump($meta);
?>

Exemplul de mai sus va afişa:

array(6) {
  ["native_type"]=>
  string(7) "integer"
  ["flags"]=>
  array(0) {
  }
  ["name"]=>
  string(8) "COUNT(*)"
  ["len"]=>
  int(-1)
  ["precision"]=>
  int(0)
  ["pdo_type"]=>
  int(2)
}

Vedeţi de asemenea

PDOStatement::columnCount() - Returns the number of columns in the result set
PDOStatement::rowCount() - Returns the number of rows affected by the last SQL statement

add a note User Contributed Notes
PDOStatement->getColumnMeta

colin at fusionbox dot com
23-Jan-2009 06:38


This method is supported in the MySQL 5.0+ driver.  It can be used for object hydration:



<?php



$pdo_stmt = $dbh->execute('SELECT discussion.id, discussion.text, comment.id, comment.text FROM discussions LEFT JOIN comments ON comment.discussion_id = discussion.id');



foreach(range(0, $pdo_stmt->columnCount() - 1) as $column_index)

{

  $meta[] = $pdo_stmt->getColumnMeta($column_index);

}



while($row = $pdo_stmt->fetch(PDO::FETCH_NUM))

{

  foreach($row as $column_index => $column_value)

  {

    //do something with the data, using the ids to establish the discussion.has_many(comments) relationship.

  }

}



?>



If you are building an ORM, this method is very useful to support more natural SQL syntax.  Most ORMs require the column names to be aliases so that they can be parsed and turned into objects that properly represent has_one, has_many, many_to_many relationships.

asohn aircanopy net
29-Feb-2008 05:21


I found a short discussion related to this function at 

http://www.sitepoint.com/forums/showthread.php?t=497257



I haven't tried it (yet?) but hopefully someone can find it useful.

add a note

PDOStatement->nextRowset

PDOStatement->getAttribute

Last updated: Fri, 20 Nov 2009