PDO::sqliteCreateFunction
(PHP 5 >= 5.1.0, PHP 7, PHP 8, PECL pdo_sqlite >= 1.0.0)
PDO::sqliteCreateFunction —
Registers a User Defined Function for use in SQL statements
Açıklama
UyarıBu işlev
DENEYSELDİR. Bu işlevin davranışı, ismi
ve belgeleri PHP'nin sonraki sürümlerinde hiçbir duyuru yapılmaksızın
değiştirilebilir. Bu risk göze alınamayacaksa bu işlev
kullanılmamalıdır.
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.
Bağımsız Değişkenler
-
function_name
-
The name of the function used in SQL statements.
-
callback
-
Callback function to handle the defined SQL function.
Bilginize:
Callback functions should return a type understood by SQLite (i.e.
scalar type).
This function need to be defined as:
-
value
-
The first argument passed to the SQL function.
-
values
-
Further arguments passed to the SQL function.
-
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.
Dönen Değerler
Başarı durumunda true
, başarısızlık durumunda false
döner.
Örnekler
Örnek 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.