Last updated: Mon, 28 Dec 2009

PDOStatement->fetch()

(PHP 5 >= 5.1.0, PECL pdo:0.1-1.0.3)

PDOStatement->fetch() — Fetches the next row from a result set

Descrição

PDOStatement

mixed fetch ([ int $fetch_style [, int $cursor_orientation [, int $cursor_offset ]]] )

Fetches a row from a result set associated with a PDOStatement object. The fetch_style parameter determines how PDO returns the row.

Parâmetros

fetch_style

Controls how the next row will be returned to the caller. This value must be one of the PDO::FETCH_* constants, defaulting to PDO::FETCH_BOTH.

PDO::FETCH_ASSOC: returns an array indexed by column name as returned in your result set
PDO::FETCH_BOTH (default): returns an array indexed by both column name and 0-indexed column number as returned in your result set
PDO::FETCH_BOUND: returns TRUE and assigns the values of the columns in your result set to the PHP variables to which they were bound with the PDOStatement->bindColumn() method
PDO::FETCH_CLASS: returns a new instance of the requested class, mapping the columns of the result set to named properties in the class. If fetch_style includes PDO::FETCH_CLASSTYPE (e.g. PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE) then the name of the class is determined from a value of the first column.
PDO::FETCH_INTO: updates an existing instance of the requested class, mapping the columns of the result set to named properties in the class
PDO::FETCH_LAZY: combines PDO::FETCH_BOTH and PDO::FETCH_OBJ, creating the object variable names as they are accessed
PDO::FETCH_NUM: returns an array indexed by column number as returned in your result set, starting at column 0
PDO::FETCH_OBJ: returns an anonymous object with property names that correspond to the column names returned in your result set

cursor_orientation

For a PDOStatement object representing a scrollable cursor, this value determines which row will be returned to the caller. This value must be one of the PDO::FETCH_ORI_* constants, defaulting to PDO::FETCH_ORI_NEXT. To request a scrollable cursor for your PDOStatement object, you must set the PDO::ATTR_CURSOR attribute to PDO::CURSOR_SCROLL when you prepare the SQL statement with PDO->prepare().

offset

For a PDOStatement object representing a scrollable cursor for which the cursor_orientation parameter is set to PDO::FETCH_ORI_ABS, this value specifies the absolute number of the row in the result set that shall be fetched.

For a PDOStatement object representing a scrollable cursor for which the cursor_orientation parameter is set to PDO::FETCH_ORI_REL, this value specifies the row to fetch relative to the cursor position before PDOStatement->fetch() was called.

Valor Retornado

The return value of this function on success depends on the fetch type. In all cases, FALSE is returned on failure.

Exemplos

Example#1 Fetching rows using different fetch styles


<?php
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();

/* Exercise PDOStatement::fetch styles */
print("PDO::FETCH_ASSOC: ");
print("Return next row as an array indexed by column name\n");
$result = $sth->fetch(PDO::FETCH_ASSOC);
print_r($result);
print("\n");

print("PDO::FETCH_BOTH: ");
print("Return next row as an array indexed by both column name and number\n");
$result = $sth->fetch(PDO::FETCH_BOTH);
print_r($result);
print("\n");

print("PDO::FETCH_LAZY: ");
print("Return next row as an anonymous object with column names as properties\n");
$result = $sth->fetch(PDO::FETCH_LAZY);
print_r($result);
print("\n");

print("PDO::FETCH_OBJ: ");
print("Return next row as an anonymous object with column names as properties\n");
$result = $sth->fetch(PDO::FETCH_OBJ);
print $result->NAME;
print("\n");
?>

O exemplo acima irá imprimir:

PDO::FETCH_ASSOC: Return next row as an array indexed by column name
Array
(
    [NAME] => apple
    [COLOUR] => red
)

PDO::FETCH_BOTH: Return next row as an array indexed by both column name and number
Array
(
    [NAME] => banana
    [0] => banana
    [COLOUR] => yellow
    [1] => yellow
)

PDO::FETCH_LAZY: Return next row as an anonymous object with column names as properties
PDORow Object
(
    [NAME] => orange
    [COLOUR] => orange
)

PDO::FETCH_OBJ: Return next row as an anonymous object with column names as properties
kiwi

Example#2 Fetching rows with a scrollable cursor


<?php
function readDataForwards($dbh) {
  $sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY BET';
  try {
    $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
    $stmt->execute();
    while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_NEXT)) {
      $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "\n";
      print $data;
    }
    $stmt = null;
  }
  catch (PDOException $e) {
    print $e->getMessage();
  }
}
function readDataBackwards($dbh) {
  $sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY bet';
  try {
    $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
    $stmt->execute();
    $row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_LAST);
    do {
      $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "\n";
      print $data;
    } while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_PRIOR));
    $stmt = null;
  }
  catch (PDOException $e) {
    print $e->getMessage();
  }
}

print "Reading forwards:\n";
readDataForwards($conn);

print "Reading backwards:\n";
readDataBackwards($conn);
?>

O exemplo acima irá imprimir:

Reading forwards:
21    10    5
16    0     5
19    20    10

Reading backwards:
19    20    10
16    0     5
21    10    5

Veja também

PDOStatement->fetchAll()

PDOStatement->execute()

Last updated: Mon, 28 Dec 2009

User Contributed Notes
PDOStatement->fetch()

daltenho at yahoo dot com
28-Jan-2008 03:17


As an alternative to marcini's suggestion:



You can use:



        $dbh->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true);



...on your PDO connection object to allow query buffering in MySQL. This will eliminate the problem of re-preparing an unclosed statement object.

Gerard van Beek
28-Oct-2007 07:42


If you to use a new instance of a class for a record you can use:



<?php

include_once("user.class");

$sth = $db->prepare("SELECT * FROM user WHERE id = 1");



/* create instance automatically */

$sth->setFetchMode( PDO::FETCH_CLASS, 'user');

$sth->execute();

$user = $sth->fetch( PDO::FETCH_CLASS );

$sth->closeCursor();

print ($user->id);



/* or create an instance yourself and use it */

$user= new user();

$sth->setFetchMode( PDO::FETCH_INTO, $user);

$sth->execute();

$user= $sth->fetch( PDO::FETCH_INTO );

$sth->closeCursor();

print ($user->id);

?>

BaBna
16-Aug-2007 04:52


When you do a SELECT query for one row, and want to check if it's there, you don't need to count the fetchAll() result, you can just check if $result->fetch() is true:

<?php

$bbnq = sprintf("SELECT login

FROM users

WHERE id = %u",27);

try

    { $req = $db_bbn->query($bbnq); }

catch (Exception $e)

    { bbnf_pdo_error($e,__FILE__,__LINE__); }

if ( $r = $req->fetch() )

    { echo "This query has a row result"; }

else

    { echo "This query has an empty result"; }

?>

dennis at inmarket dot lviv dot ua
07-Apr-2007 10:18


Regarding the two previous notes - I downloaded the "latest CVS" a week ago for Windows and was surprised to notice that this issue is gone there, ie you don't have to close cursor before doing next query.

redcube
05-Apr-2007 06:53


as an alternative for marcini's note:



just clear the statement variable before you issue another query:



<?php



$stmt = $db->prepare('SELECT * FROM test');



// fetch only the first row

$row = $stmt->fetch(PDO::FETCH_ASSOC);



// clear the variable so its contents are destroyed (including the other rows in the result)

$stmt = null;



// now you can issue another query

$stmt = $db->prepare('SELECT * FROM test2');

?>

marcini
02-Apr-2007 08:41


Be careful with fetch() when you use prepared statements and MySQL (I don`t know how it is with other databases). Fetch won`t close cursor and won`t let you send any other query, even if your result set has only one row, . 

If you use $statement->fetch(), you will also have to use $statement->closeCursor() afterwards, to be albe to execute another query.

Alternatively you can use $statement->fetchAll() without $statement->closeCursor().

PDOStatement->fetchAll()

PDOStatement->execute()

Last updated: Mon, 28 Dec 2009