search
HomeBackend DevelopmentPHP TutorialHow is PHP PDO preprocessing cached?

Recently, preprocessing SQL (prepare) is used for the following two reasons.

  1. High efficiency.

  2. Prevent SQL injection.

Read the official document, php.net data object

But it still feels a bit confusing to use.

Whether the efficiency will be improved? If the preprocessing is the same preprocessing SQL and just changes the parameters, then I think the efficiency will definitely be improved: However, if it is the following situation:

<code>//1. 在参数数量不一致的时候不能使用同一个预处理SQL。如下要使用两个预处理语句。
SELECT name FROM product WHERE product_id in (?, ?, ?, ?);
SELECT name FROM product WHERE product_id in (?, ?, ?, ?, ?);

//PS: 如果是参数数量比较多的话,不知道效率会不会比直接(12, 34, 45, 23...)慢,但直接用id列表不能预防SQL注入。

//2. 每次执行完预处理之后,再次执行相同的预处理,会不会速度更快。
$sql = 'SELECT name FROM product where product_id = ?';
$statement = PDO::prepare($preSql);

$product_id = 111;
$statement.bindParam(1, $product_id);
$statement->execute();

/*
最理想的情况是除掉注释的,直接使用$statement调用两次。
但是,平常一些SQL操作并不是这么连贯(同类型的SQL可能分开执行),并不好分析。
不能缓存$statement, 然后调用同一个$statement.
如果第一次执行完成后,方法已经结束(资源释放),第二次执行又重新prepare相同的SQL。
这时候不知道会不会调用缓存的预处理SQL,如果是缓存在DB,应该可以调用。
但如果缓存在PHP的话,感觉应该又要重新处理了,这样感觉没有直接使用不预处理的SQL效率高。
*/

//$sql = 'SELECT name FROM product where product_id = ?';
//$statement = PDO::prepare($preSql);

$product_id = 123;
//$statement.bindParam(1, $product_id);
$statement->execute();

/*
同理在处理ORDER的时候,如果缓存能生效使用参数,是最好的.
这样的话,就可以不用重新预处理SQL。也可以防SQL注入。
*/
</code>

I feel like writing this, the most important thing is to know how PDO perpare is cached? Or there is a similar document (English is also acceptable).

Reply content:

Recently, preprocessing SQL (prepare) is used for the following two reasons.

  1. High efficiency.

  2. Prevent SQL injection.

Read the official document, php.net data object

But it still feels a bit confusing to use.

Whether the efficiency will be improved? If the preprocessing is the same preprocessing SQL and just changes the parameters, then I think the efficiency will definitely be improved: However, if it is the following situation:

<code>//1. 在参数数量不一致的时候不能使用同一个预处理SQL。如下要使用两个预处理语句。
SELECT name FROM product WHERE product_id in (?, ?, ?, ?);
SELECT name FROM product WHERE product_id in (?, ?, ?, ?, ?);

//PS: 如果是参数数量比较多的话,不知道效率会不会比直接(12, 34, 45, 23...)慢,但直接用id列表不能预防SQL注入。

//2. 每次执行完预处理之后,再次执行相同的预处理,会不会速度更快。
$sql = 'SELECT name FROM product where product_id = ?';
$statement = PDO::prepare($preSql);

$product_id = 111;
$statement.bindParam(1, $product_id);
$statement->execute();

/*
最理想的情况是除掉注释的,直接使用$statement调用两次。
但是,平常一些SQL操作并不是这么连贯(同类型的SQL可能分开执行),并不好分析。
不能缓存$statement, 然后调用同一个$statement.
如果第一次执行完成后,方法已经结束(资源释放),第二次执行又重新prepare相同的SQL。
这时候不知道会不会调用缓存的预处理SQL,如果是缓存在DB,应该可以调用。
但如果缓存在PHP的话,感觉应该又要重新处理了,这样感觉没有直接使用不预处理的SQL效率高。
*/

//$sql = 'SELECT name FROM product where product_id = ?';
//$statement = PDO::prepare($preSql);

$product_id = 123;
//$statement.bindParam(1, $product_id);
$statement->execute();

/*
同理在处理ORDER的时候,如果缓存能生效使用参数,是最好的.
这样的话,就可以不用重新预处理SQL。也可以防SQL注入。
*/
</code>

I feel like writing this, the most important thing is to know how PDO perpare is cached? Or there is a similar document (English is also acceptable).

The main functions of prepared statements are as follows:
1. It is safer. PDO or the underlying database library will take special care of bind variables that do not take constraints. If you always use prepared statements, you will not Vulnerable to SQL injection attacks.
2. Sometimes queries may be faster. Many databases cache prepared statements in query plans and use symbolic references to prepared statements instead of retransmitting the entire query text. The most obvious thing is that you only need to declare a prepared statement object once and then reuse the prepared statement object when encountering different variables.

Of the two, safety is obviously more important, which makes prepared statements indispensable. If it is efficient, I think it may be that it uses the same object in multiple preprocessing, which improves efficiency.

Original post

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
php怎么把负数转为正整数php怎么把负数转为正整数Apr 19, 2022 pm 08:59 PM

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

php怎么实现几秒后执行一个函数php怎么实现几秒后执行一个函数Apr 24, 2022 pm 01:12 PM

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php怎么除以100保留两位小数php怎么除以100保留两位小数Apr 22, 2022 pm 06:23 PM

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

php怎么根据年月日判断是一年的第几天php怎么根据年月日判断是一年的第几天Apr 22, 2022 pm 05:02 PM

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php怎么替换nbsp空格符php怎么替换nbsp空格符Apr 24, 2022 pm 02:55 PM

方法:1、用“str_replace("&nbsp;","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\&nbsp\;||\xc2\xa0)/","其他字符",$str)”语句。

php怎么判断有没有小数点php怎么判断有没有小数点Apr 20, 2022 pm 08:12 PM

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

php怎么设置implode没有分隔符php怎么设置implode没有分隔符Apr 18, 2022 pm 05:39 PM

在PHP中,可以利用implode()函数的第一个参数来设置没有分隔符,该函数的第一个参数用于规定数组元素之间放置的内容,默认是空字符串,也可将第一个参数设置为空,语法为“implode(数组)”或者“implode("",数组)”。

php字符串有没有下标php字符串有没有下标Apr 24, 2022 am 11:49 AM

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!