PHP Dokumentation: Pdostatement fetch
12. Januar 2010 von werner
PDOStatement->fetch
(PHP 5 >= 5.1.0, PECL pdo >= 0.1.0)
PDOStatement->fetch — Fetches the next row from a result set
Beschreibung
Fetches a row from a result set associated with a PDOStatement object. The fetch_style parameter determines how PDO returns the row.
Parameter-Liste
- 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.
Rückgabewerte
The return value of this function on success depends on the fetch type. In all cases, FALSE is returned on failure.
Beispiele
Beispiel #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 $result->NAME;
print("\n");
?>Das oben gezeigte Beispiel erzeugt folgendeAusgabe:
PDO::FETCH_ASSOC: Return next row as an array indexed by column nameArray( [NAME] => apple [COLOUR] => red)PDO::FETCH_BOTH: Return next row as an array indexed by both column name and numberArray( [NAME] => banana [0] => banana [COLOUR] => yellow [1] => yellow)PDO::FETCH_LAZY: Return next row as an anonymous object with column names as propertiesPDORow Object( [NAME] => orange [COLOUR] => orange)PDO::FETCH_OBJ: Return next row as an anonymous object with column names as propertieskiwi
Beispiel #2 Fetching rows with a scrollable cursor
<?php
function readDataForwards($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);
?>Das oben gezeigte Beispiel erzeugt folgendeAusgabe:
Reading forwards:21 10 516 0 519 20 10Reading backwards:19 20 1016 0 521 10 5
Siehe auch
- PDO::prepare() – Prepares a statement for execution and returns a statement object
- PDOStatement::execute() – Executes a prepared statement
- PDOStatement::fetchAll() – Returns an array containing all of the result set rows
- PDOStatement::fetchColumn() – Returns a single column from the next row of a result set
- PDOStatement::fetchObject() – Fetches the next row and returns it as an object.
- PDOStatement::setFetchMode() – Set the default fetch mode for this statement
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