PHP 7.2.0 Release Candidate 4 Released

PDO::sqliteCreateFunction

(PHP 5 >= 5.1.0, PHP 7, PECL pdo_sqlite >= 1.0.0)

PDO::sqliteCreateFunction Registers a User Defined Function for use in SQL statements

Descrierea

public bool PDO::sqliteCreateFunction ( string $function_name , callable $callback [, int $num_args = -1 [, int $flags = 0 ]] )
Avertizare

Această funcție este EXPERIMENTALĂ. Comportamentul acestei funcții, denumirea sa și orice alte aspecte documentate în privința acestei funcții pot să fie modificate fără preaviz într-o versiune viitoare a PHP. Utilizați această funcție la propriul risc.

This method allows you to register a PHP function with SQLite as an UDF (User Defined Function), so that it can be called from within your SQL statements.

The UDF can be used in any SQL statement that can call functions, such as SELECT and UPDATE statements and also in triggers.

Parametri

function_name

The name of the function used in SQL statements.

callback

Callback function to handle the defined SQL function.

Notă: Callback functions should return a type understood by SQLite (i.e. scalar type).

num_args

The number of arguments that the SQL function takes. If this parameter is -1, then the SQL function may take any number of arguments.

flags

A bitwise conjunction of flags. Currently, only PDO::SQLITE_DETERMINISTIC is supported, which specifies that the function always returns the same result given the same inputs within a single SQL statement.

Valorile întoarse

Întoarce valoarea TRUE în cazul succesului sau FALSE în cazul eșecului.

Istoricul schimbărilor

Versiune Descriere
PHP 7.1.4 The flags has been added.

Exemple

Example #1 PDO::sqliteCreateFunction() example

<?php
function md5_and_reverse($string
{
    return 
strrev(md5($string));
}

$db = new PDO('sqlite:sqlitedb');
$db->sqliteCreateFunction('md5rev''md5_and_reverse'1);
$rows $db->query('SELECT md5rev(filename) FROM files')->fetchAll();
?>

In this example, we have a function that calculates the md5 sum of a string, and then reverses it. When the SQL statement executes, it returns the value of the filename transformed by our function. The data returned in $rows contains the processed result.

The beauty of this technique is that you do not need to process the result using a foreach loop after you have queried for the data.

Sfat

You can use PDO::sqliteCreateFunction and PDO::sqliteCreateAggregate to override SQLite native SQL functions.

Notă:

This method is not available with the SQLite2 driver. Use the old style sqlite API for that instead.

A se vedea și

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User Contributed Notes 1 note

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1
RoboTamer
5 years ago
groups looks like this '1,2,3,999'

<?php
/**
* int strpos ( string $haystack , mixed $needle [, int $offset = 0 ] )
*/
$dbUser = new PDO('sqlite:'.ROOT.'/var/db/users.db3');
$dbUser->sqliteCreateFunction('strpos', 'strpos', 2);
$sql = 'SELECT username FROM users WHERE strpos(groups,",2,");';
$rows = $dbUser->query($sql)->fetchAll(PDO::FETCH_ASSOC);
print_r($rows);

?>
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