Registers a PHP function for use as an SQL scalar function

说明

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.

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.

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.

返回值

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

更新日志

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

范例

示例 #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"