SQLite3::createFunction
(PHP 5 >= 5.3.0)
SQLite3::createFunction — Registers a PHP function for use as an SQL scalar function
说明
$name
, mixed $callback
[, int $argument_count = -1
] )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 negative, then the SQL function may take any number of arguments.
返回值
Returns TRUE upon successful creation of the function, FALSE on failure.
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"
用户评论:
[#1] bohwaz [2012-02-28 14:45:09]
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).
[#2] koalay at gmail dot com [2010-05-26 07:43:53]
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)");
?>