PHP kézikönyv
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# PDOStatement::fetch

(no version information, might be only in CVS)

PDOStatement::fetch -- Fetches the next row from a result set

## Leírás

mixed PDOStatement::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.

## Paraméterek

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::bindParam() 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.

## Példák

Példa 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");
?>`

A fenti példa a következő kimenetet adja:

    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

Példa 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);
?>`

A fenti példa a következő kimenetet adja:

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

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

## Lásd még

PDO::query()
PDOStatement::fetchAll()
PDOStatement::fetchColumn()
PDOStatement::prepare()
PDOStatement::setFetchMode()

Előző | Tartalom | Következő
PDOStatement::execute | Fel | PDOStatement::fetchAll