Pleas note the following:
If you try binding a column name, that is not existent in the result set referenced by your PDOStatement there will be a warning issued regardless of your PDO ATTR_ERRMODE setting. You can supress that warning using the @ supression operator, but there is no other way of finding out if an column you try to bind actually exist other than inspecting error_get_last( ) and it's fellow companions.
Also refer to this bug report http://bugs.php.net/bug.php?id=52104
PDOStatement::bindColumn
(PHP 5 >= 5.1.0, PECL pdo >= 0.1.0)
PDOStatement::bindColumn — Bind a column to a PHP variable
Descrizione
$column
, mixed &$param
[, int $type
[, int $maxlen
[, mixed $driverdata
]]] )PDOStatement::bindColumn() arranges to have a particular variable bound to a given column in the result-set from a query. Each call to PDOStatement::fetch() or PDOStatement::fetchAll() will update all the variables that are bound to columns.
Nota:
Since information about the columns is not always available to PDO until the statement is executed, portable applications should call this function after PDOStatement::execute().
However, to be able to bind a LOB column as a stream when using the PgSQL driver, applications should call this method before calling PDOStatement::execute(), otherwise the large object OID will be returned as an integer.
Elenco dei parametri
-
column -
Number of the column (1-indexed) or name of the column in the result set. If using the column name, be aware that the name should match the case of the column, as returned by the driver.
-
param -
Name of the PHP variable to which the column will be bound.
-
type -
Data type of the parameter, specified by the PDO::PARAM_* constants.
-
maxlen -
A hint for pre-allocation.
-
driverdata -
Optional parameter(s) for the driver.
Valori restituiti
Restituisce TRUE in caso di successo, FALSE in caso di fallimento.
Esempi
Example #1 Binding result set output to PHP variables
Binding columns in the result set to PHP variables is an effective way to make the data contained in each row immediately available to your application. The following example demonstrates how PDO allows you to bind and retrieve columns with a variety of options and with intelligent defaults.
<?php
function readData($dbh) {
$sql = 'SELECT name, colour, calories FROM fruit';
try {
$stmt = $dbh->prepare($sql);
$stmt->execute();
/* Bind by column number */
$stmt->bindColumn(1, $name);
$stmt->bindColumn(2, $colour);
/* Bind by column name */
$stmt->bindColumn('calories', $cals);
while ($row = $stmt->fetch(PDO::FETCH_BOUND)) {
$data = $name . "\t" . $colour . "\t" . $cals . "\n";
print $data;
}
}
catch (PDOException $e) {
print $e->getMessage();
}
}
readData($dbh);
?>
Il precedente esempio visualizzerĂ :
apple red 150 banana yellow 175 kiwi green 75 orange orange 150 mango red 200 strawberry red 25
Vedere anche:
- PDOStatement::execute() - Executes a prepared statement
- PDOStatement::fetch() - Fetches the next row from a result set
- 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
