SQLite3::createFunction

(PHP 5 >= 5.3.0, PHP 7)

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

说明

public bool SQLite3::createFunction ( string $name , mixed $callback [, int $argument_count = -1 [, int $flags = 0 ]] )

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

参数

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.
argument_count: 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.

返回值

Returns TRUE upon successful creation of the function, FALSE on failure.

更新日志

版本	说明
PHP 7.1.4	The `flags` has been added.

范例

Example #1 SQLite3::createFunction() example


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

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

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

以上例程的输出类似于：

string(32) "098f6bcd4621d373cade4e832627b4f6"

User Contributed Notes

bohwaz 28-Feb-2012 11:45


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).

koalay at gmail dot com 26-May-2010 04:43


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)");



?>