SQLite3::createFunction

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

SQLite3::createFunction — Registers a PHP function for use as an SQL scalar function

Descrizione

public SQLite3::createFunction(
    string $name,
    callable $callback,
    int $argCount = -1,
    int $flags = 0
): bool

Registers a PHP function or user-defined function for use as an SQL scalar function for use within SQL statements.

Elenco dei parametri

name

Name of the SQL function to be created or redefined.

callback

The name of a PHP function or user-defined function to apply as a callback, defining the behavior of the SQL function.

This function need to be defined as:

callback(mixed $value, mixed ...$values): mixed

value: The first argument passed to the SQL function.
values: Further arguments passed to the SQL function.

argCount

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 SQLITE3_DETERMINISTIC is supported, which specifies that the function always returns the same result given the same inputs within a single SQL statement.

Valori restituiti

Returns true upon successful creation of the function, false on failure.

Log delle modifiche

Versione	Descrizione
7.1.4	The `flags` parameter has been added.

Esempi

Example #1 SQLite3::createFunction() example

<?php
function my_udf_md5($string) {
    return hash('md5', $string);
}

$db = new SQLite3('mysqlitedb.db');
$db->createFunction('my_udf_md5', 'my_udf_md5');

var_dump($db->querySingle('SELECT my_udf_md5("test")'));
?>

Il precedente esempio visualizzerà qualcosa simile a:

string(32) "098f6bcd4621d373cade4e832627b4f6"

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User Contributed Notes 2 notes

down

koalay at gmail dot com ¶

14 years ago

Since regular expression is not supported by default SQLite, we can create a user function to do the job.

<?php

$db = new SQLite3("database.sqlit3", 0666);

// create a function named "preg_match"
// with the php core function "preg_match"
if ($db->createFunction("preg_match", "preg_match", 2) === FALSE)
  exit("Failed creating function\n");

// this query will then works as expected
$result = $db->query("SELECT * FROM table1 WHERE 
  preg_match('/^(apple|orange)$/', variable1)");

?>

down

-1

bohwaz ¶

12 years ago

In PHP 5.4 there will be a createCollation method to use your custom collation method, to be able to sort datasets using unicode, like this:

<?php
setlocale(LC_COLLATE, 'fr_FR.UTF-8');
$db->createCollation('PHP_COLLATE', 'strcoll');

$db->query('SELECT * FROM my_table ORDER BY name COLLATE PHP_COLLATE;');
?>

But until this cool feature becomes available, you'll have to do some tricks, like this for french:

<?php
function sqlite3_to_ascii($str, $charset = 'UTF-8')
{
    // Don't process empty strings
    if (!trim($str))
        return $str;

    // We only process non-ascii strings
    if (preg_match('!^[[:ascii:]]+$!', $str))
        return $str;

    $str = htmlentities($str, ENT_NOQUOTES, $charset);

    $str = preg_replace('#&([A-za-z])(?:acute|cedil|circ|grave|orn|ring|slash|th|tilde|uml);#', '\1', $str);
    $str = preg_replace('#&([A-za-z]{2})(?:lig);#', '\1', $str);
    $str = preg_replace('#&[^;]+;#', '', $str);

    return $str;
}

$db->createFunction('to_ascii', 'sqlite3_to_ascii', 1);
$res = $db->query('SELECT * FROM test ORDER BY to_ascii(text);');
?>

This will convert non-ascii characters to ascii ones before collation. In fact this won't work with non-latin languages, but for latin-languages it's better than nothing.

Please note that this will slow down about 1.8 times the query (tested on a 10.000 rows table).

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