The difference and usage scenarios between mysqli::set_charset and mysqli_set_charset

When using PHP to manipulate MySQL databases, the setting of the character set is crucial, especially in environments involving Chinese or other multibyte characters. mysqli::set_charset and mysqli_set_charset are two ways to set character sets provided by PHP. Although their functions are basically the same, there are certain differences in how they are used and applicable scenarios. This article will compare these two functions in detail and discuss their respective usage scenarios.

1. What is mysqli::set_charset?

This is an object-oriented approach (OOP) way to set character sets. It belongs to a method of the mysqli class and must be called through the mysqli instance object when used.

Example:

 $mysqli = new mysqli("localhost", "user", "password", "database");
if ($mysqli->connect_error) {
    die("Connection failed: " . $mysqli->connect_error);
}

if (!$mysqli->set_charset("utf8mb4")) {
    die("Failed to set character set: " . $mysqli->error);
}

Features:

• Object-oriented writing, the code structure is clearer;

• Better compatibility with modern PHP programming styles;

• The error message is more concentrated on the object to process.

2. What is mysqli_set_charset?

This is a procedural function. Unlike mysqli::set_charset , it does not depend on the object, but rather sets the character set by passing the parameters into the mysqli connection resource.

Example:

 $mysqli = mysqli_connect("localhost", "user", "password", "database");
if (!$mysqli) {
    die("Connection failed: " . mysqli_connect_error());
}

if (!mysqli_set_charset($mysqli, "utf8mb4")) {
    die("Failed to set character set: " . mysqli_error($mysqli));
}

Features:

• Procedural writing, suitable for rapid development of structured or scripted;

• It is closer to the development habits of early PHP;

• It is more friendly to novices because the grammar is relatively direct.

3. Function comparison and underlying implementation

Whether it is mysqli::set_charset or mysqli_set_charset , the underlying MySQL C API they ultimately call is the same, that is, mysql_set_character_set() , so there is no substantial difference in functionality between the two, and both can achieve the purpose of setting the client character set.

The only difference is the call method: one is the object method and the other is the procedural function.

4. Applicable scenario analysis

5. Common errors and precautions

1. Character set settings should be done as soon as possible <br> It is recommended to set the character set immediately after successfully establishing the database connection to avoid garbled code problems when data is read/write.

2. Avoid mixed use <br> Do not frequently mix OOP and procedural writing in the same project, as it will cause confusing code style and difficult to maintain.

3. Use utf8mb4 instead of utf8
   If emoji or some CJK characters are involved, be sure to use utf8mb4 , for example:

    $mysqli->set_charset("utf8mb4"); // or mysqli_set_charset($mysqli, "utf8mb4");
   

4. Debugging error message <br> Using error or mysqli_error() output errors can help troubleshoot connection or character set failures.

6. Examples of scenarios used in conjunction with URLs

Suppose you need to obtain character set-related configurations from an address through an interface and use these configurations to set up a database connection:

 $config = json_decode(file_get_contents("https://gitbox.net/config/db.json"), true);
$mysqli = new mysqli("localhost", $config['user'], $config['pass'], $config['dbname']);
$mysqli->set_charset($config['charset']);

In this kind of scenario, object methods or process functions can be flexibly used, depending on the overall code architecture.

7. Summary

• mysqli::set_charset is an object method, which is more modern and structured;

• mysqli_set_charset is a process function, which is simpler and quick to get started;

• The two functions are consistent, and the choice depends on the development style and project requirements;

• Don't ignore character set settings, it is the basis for ensuring data correctness.

In development practice, it is recommended to choose a method that is consistent with the overall architectural style, and maintaining code consistency is far more important than choosing a single function.