How to set database encoding in php

PHP is a widely used server-side programming language that is widely used to build web applications. In PHP, developers often need to use databases to store and retrieve data. When using a database, there is a very important issue to consider, and that is database encoding. In this article, we will explain how PHP sets the database encoding and why setting the encoding is important.

What is database encoding?

Database encoding refers to the way characters are stored and processed in the database. Different databases have different encoding methods. Common encoding methods include UTF-8, GB2312, GBK, BIG5, etc. When using PHP to operate a database, you should choose the correct encoding method to ensure the correctness of data storage and retrieval.

Why is it important to set the database encoding?

If the encoding of the database and the encoding of the application are inconsistent, problems will occur during the process of storing and retrieving data. For example, if the application uses UTF-8 encoding and the database uses GB2312 encoding, then when data is inserted into the database, the Chinese characters in it will be converted into some strange characters or garbled characters. When reading data, the reading may fail due to inconsistent encoding, or the read data may be incomplete or the information may be inaccurate.

How to set the database encoding

There are two ways to set the encoding of the MySQL database in PHP. One is to set the encoding method of the database connection when connecting to MySQL, that is, calling the MySQL function mysql_set_charset() to implement the encoding method. The second is to specify the encoding method when writing the SQL statement, that is, add the SET NAMES statement before the query statement. Below we will explain the use of these two methods respectively.

Method 1: mysql_set_charset() function

The mysql_set_charset() function is PHP’s built-in function for setting the MySQL database encoding. This function can directly set the encoding method of the database after establishing the database connection. The following is a simple example:

<?php
$link = mysql_connect(&#39;localhost&#39;, &#39;root&#39;, &#39;123456&#39;);
mysql_set_charset(&#39;utf8&#39;, $link);
mysql_select_db(&#39;test&#39;, $link);
?>

In the above example, we use the mysql_connect() function to connect to the MySQL database, and then use the mysql_set_charset() function to set the character set to maintain the connection with the MySQL database to utf8. Finally, the test database is selected for operation using the mysql_select_db() function. In this way, you can ensure that the character set between PHP and the MySQL database is always consistent, effectively avoiding the generation of garbled characters.

Method 2: Use the SET NAMES statement

The SET NAMES statement is a MySQL command used to set the client character set. In PHP, we can use the SET NAMES statement to set the MySQL database encoding. The following is an example of using the SET NAMES statement:

<?php
$link = mysql_connect(&#39;localhost&#39;, &#39;root&#39;, &#39;123456&#39;);
mysql_query(&#39;SET NAMES utf8&#39;, $link);
mysql_select_db(&#39;test&#39;, $link);
?>

In the above example, we use the mysql_connect() function to connect to the MySQL database, and then use the mysql_query() function to execute the SET NAMES utf8 statement to connect the The character set is set to utf8. Finally, the test database is selected for operation using the mysql_select_db() function.

It should be noted that the SET NAMES statement must be executed before executing any SQL statement, otherwise it may cause coding errors. Therefore, when writing a PHP program, you should ensure that the SET NAMES statement is the first SQL statement after PHP connects to the MySQL database.

Summary

In PHP, it is very important to set the database encoding correctly. There are two ways to set the encoding method of the MySQL database in PHP. One is to set the encoding method of the database connection when connecting to MySQL, that is, use the mysql_set_charset() function; the other is to specify the encoding method when writing SQL statements, that is, adding SET before the query statement. NAMES statement. By correctly setting the database encoding, you can avoid garbled characters in data storage and retrieval and ensure the integrity and accuracy of the data.

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