PHP - Manual: PDO::sqliteCreateFunction

2024-12-22

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

说明

public PDO::sqliteCreateFunction(
    string $function_name,
    callable $callback,
    int $num_args = -1,
    int $flags = 0
): bool

警告

此函数是实验性的。此函数的表象，包括名称及其相关文档都可能在未来的 PHP 发布版本中未通知就被修改。使用本函数风险自担。

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.

参数

function_name

The name of the function used in SQL statements.

callback

Callback function to handle the defined SQL function.

注意: Callback functions should return a type understood by SQLite (i.e. scalar type).

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.

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.

返回值

成功时返回 true，或者在失败时返回 false。

更新日志

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

范例

示例 #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.

小技巧

You can use PDO::sqliteCreateFunction and PDO::sqliteCreateAggregate to override SQLite native SQL functions.

参见

PDO::sqliteCreateAggregate
sqlite_create_function()
sqlite_create_aggregate()

add a note

User Contributed Notes 1 note

down

-2

RoboTamer ¶

9 years ago


groups looks like this '1,2,3,999'

<?php 
/**
 * int strpos ( string $haystack , mixed $needle [, int $offset = 0 ] )
 */
$dbUser = new PDO('sqlite:'.ROOT.'/var/db/users.db3');
$dbUser->sqliteCreateFunction('strpos', 'strpos', 2);
$sql = 'SELECT username FROM users WHERE strpos(groups,",2,");';
$rows = $dbUser->query($sql)->fetchAll(PDO::FETCH_ASSOC);
print_r($rows);

?>

add a note

官方地址：https://www.php.net/manual/en/pdo.sqlitecreatefunction.php

有任何技术问题请点击这里网站运营推广招聘

IT PHP 编程语言 Linux 开发编程科技 Elasticsearch HTML/CSS/XML 网络数据库 JAVA 面试 NoSQL C/C++ Golang Git 算法操作系统正则表达式 Redis 互联网 MySql JavaScript 运维软件国际架构设计 Mac OS TCP/IP Excel Vim Windows Socket Oracle VR MongoDB Python 运营 MemCache 商业硬件电子娱乐设计 nginx 摄影游戏 WordPress HTTP 团建数码电器

php7 安装fileinfo扩展 preg_split — 通过一个正则表达式分隔字符串 php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题 [PHP] inet_pton/inet_ntop IP地址转换函数 PHP 8.1 [鸟哥]PHP_INT_MIN 和 -9223372036854775808 adodb手册 ADORecordSet对象 opcache预加载 Composer的Packagist资源 array_multisort() 多字段排序 PHPMailer设置utf8 PHPMailer字符集CharSet mysql面试题 PHP json解析（json_decode）页面工具纯php实现DES以及TripleDES加密算法 php中几种注释规范 php 修改图片大小两千行PHP学习笔记支持php7的性能采集扩展 [原创]诡异的php-fpm超时问题

略微加速

PHP官方手册 - 互联网笔记

PDO::sqliteCreateFunction

说明

参数

返回值

更新日志

范例

参见

User Contributed Notes 1 note