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In PHP, character set settings are crucial to the correct processing of the database when operating a MySQL database. The correct character set can avoid garbled code and ensure the correct storage and retrieval of data. mysqli::get_charset and mysqli_query("SET NAMES...") are both ways to handle character sets, but their functions and usage are different. This article will compare the differences and applicable scenarios of the two in detail.
mysqli::get_charset is a method in the mysqli extension to get the character set of the currently connected. It does not modify the character set, but returns the character set information used by the current database connection.
$charset = $mysqli->get_charset();
This method returns an object containing character set information, which contains the following content:
charset : The name of the character set currently used.
collation : The proofreading rules for the current character set.
<?php
$mysqli = new mysqli("localhost", "username", "password", "database");
if ($mysqli->connect_error) {
die("Connection failed: " . $mysqli->connect_error);
}
$charset = $mysqli->get_charset();
echo "Current character set: " . $charset->charset . "<br>";
echo "Current proofreading rules: " . $charset->collation . "<br>";
$mysqli->close();
?>
mysqli::get_charset is mainly used to check the character set used by the current connection in the program. This is very useful for debugging or logging, especially when multiple connections and modifying character sets.
SET NAMES is a SQL statement that is used to set up the character set of connections after establishing a connection to a MySQL database. This setting affects all subsequent queries and data exchanges on the connection, ensuring consistency of the character set.
mysqli_query($conn, "SET NAMES 'charset_name'");
where charset_name is the character set name to be set (for example utf8 or utf8mb4 ).
<?php
$mysqli = new mysqli("localhost", "username", "password", "database");
if ($mysqli->connect_error) {
die("Connection failed: " . $mysqli->connect_error);
}
// Set the character set to utf8mb4
mysqli_query($mysqli, "SET NAMES 'utf8mb4'");
// Confirm character set settings
$result = $mysqli->query("SHOW VARIABLES LIKE 'character_set_client'");
$row = $result->fetch_assoc();
echo "Current character set设置: " . $row['Value'] . "<br>";
$mysqli->close();
?>
The SET NAMES statement is suitable for ensuring that the character set of the database connection is set to the specified value after each connection. Especially when dealing with different encoded data, it is important to ensure that the character set is consistent. For example, when the data stored in the database is encoded using UTF-8, SET NAMES 'utf8mb4' should be used to ensure character set consistency and avoid garbled code when inserting data.
mysqli::get_charset : is used only to get the character set of the current connection and will not modify any settings. It is used to check the current character set state.
mysqli_query("SET NAMES...") : Used to set the character set of the current connection. This command ensures that subsequent queries are encoded and decoded using the specified character set.
mysqli::get_charset : is usually used when you need to get and confirm the current character set, such as debugging or logging.
mysqli_query("SET NAMES...") : Usually, the character set is set immediately after connecting to the database, especially when data insertion or update, ensuring character set consistency.
mysqli::get_charset : No SQL statement is required when calling, it is directly accessed through the connection object.
mysqli_query("SET NAMES...") : An SQL statement is required to be executed, suitable for scenarios where database queries are executed.
Using mysqli::get_charset can easily obtain the character set information of the current connection, which is suitable for debugging or verifying a character set.
Use mysqli_query("SET NAMES...") to set the character set after the database connection, ensuring that all subsequent queries use the correct character set.
No matter which method you choose, it needs to be decided based on actual needs. Generally speaking, setting up character sets after connecting to a database is usually recommended to ensure the integrity and correctness of the data. Mysqli::get_charset is more used to check or confirm the character set status of the connection.
