PHP is a widely used server-side programming language that can be used to develop web applications. At the same time, MySQL is one of the most popular relational database management systems in the world. In web application development, it is often necessary to use PHP to connect to the MySQL database. Therefore, it is very important to set the encoding correctly. This article will introduce you to this knowledge.
1. Basic knowledge of database encoding
Before we start to introduce how to set up encoding, we need to understand some basic knowledge of database encoding.
1.1 Character set
Character set is a set of encoding rules used to represent characters. It can convert characters into a unique binary code to facilitate computer processing, storage and transmission. In MySQL, commonly used character sets include ASCII, UTF-8, GB2312, GBK, etc.
1.2 Proofset
Proofset is a set of rules for comparing and sorting characters. It defines the weight and order of different characters in sorting. The collation sets supported by MySQL include utf8_general_ci, utf8_unicode_ci, gbk_chinese_ci, etc.
1.3 Encoding
Encoding is the process of converting characters in a character set into binary encoding according to certain rules, such as converting UTF-8 encoded characters into GB2312 encoded characters.
2. Encoding settings for PHP connection to MySQL database
When connecting to MySQL database in PHP, you need to pay attention to the following aspects of encoding settings.
2.1 Encoding settings for PHP script files
First, you need to set the encoding format of the PHP script file to ensure that the data read from the script file is encoded correctly. You can use the following code in the file header to set the encoding format:
header('Content-type:text/html;charset=utf-8');
This will set the encoding format to UTF-8.
2.2 Encoding settings for database connection
When connecting to the MySQL database, you need to set the correct character set and collation set in order to correctly process and store data. You can use the following code to connect to the MySQL database:
$db = mysqli_connect('localhost', 'username', 'password', 'dbname'); mysqli_set_charset($db, 'utf8');
Among them, the mysqli_set_charset() function is used to set the encoding format of the database connection to UTF-8.
2.3 Encoding settings for database operations
When performing database operations, the character set and collation set used need to be set to correct values. You can use the following code to set it before accessing the database:
mysqli_query($db, 'SET NAMES utf8');
This will set the encoding format to UTF-8.
2.4 Encoding settings for database query results
When querying the database, you need to ensure that the returned data is encoded correctly. You can use the following code to set it:
mysqli_query($db, 'SET NAMES utf8'); $res = mysqli_query($db, 'SELECT name FROM users'); mysqli_fetch_row($res, MYSQLI_ASSOC);
This way you can get the correct data encoding.
3. Summary
The above is an introduction to the encoding settings for PHP connection to the MySQL database. It is very important to set the encoding correctly to ensure that data will not be garbled during storage, transmission and processing, thereby ensuring the normal operation and user experience of web applications.
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