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In PHP, we often need to deal with the character set when database connections, especially when the data stored in the database contains non-ASCII characters, making sure the character set is set correctly. The mysqli::get_charset function is used to obtain the character set (charset) used by the current database connection. However, some developers find that the returned character set is always latin1 when using this function, even if they have set other character sets (such as UTF-8) when connecting to the database. So, why does this happen? What exactly went wrong?
First, the function of the mysqli::get_charset function is to return the character set information associated with the current database connection. This character set is the character set used when the database connects, not the default character set of the database itself. The basic syntax is as follows:
$charset = $mysqli->get_charset();
Where $charset will contain the character set information of the currently connected.
When you find that the character set returned by mysqli::get_charset is latin1 , there are usually the following reasons:
When you use the mysqli extension to establish a database connection, you need to specify the character set explicitly. If the character set is not set when connecting to the database, or if the setting is incorrect, mysqli will use the latin1 character set by default. Even if the default character set of the database itself is UTF-8, the connection will still use latin1 if the character set is not explicitly set in PHP.
The character set can be explicitly set through the set_charset method:
$mysqli = new mysqli('localhost', 'username', 'password', 'database');
// Set the character set to UTF-8
$mysqli->set_charset('utf8');
// Get the current character set
$charset = $mysqli->get_charset();
echo $charset->charset;
The set_charset('utf8') in the above code tells the database connection to use UTF-8 encoding, so that Unicode characters can be correctly processed in subsequent operations.
Even if the character set is set in PHP code, if the default character set of the database itself is set to latin1 , it may affect the returned character set when the database connection is established. Check your database configuration to make sure the database's default character set is correct (e.g. UTF-8). You can view the default character set of the database through the following SQL query:
SHOW VARIABLES LIKE 'character_set_database';
In addition to the character set of the database itself, the character sets of data tables and columns may also affect the display of the character set. Character encoding problems may occur if the character set of a table or column does not match the character set set when concatenated. The character sets of tables and columns can be viewed through the following SQL queries:
SHOW TABLE STATUS WHERE name = 'your_table_name';
Alternatively, look at the character set for a specific column:
SHOW FULL COLUMNS FROM your_table_name;
The core of solving this problem is to ensure that the database connection is used in PHP code. The specific methods are as follows:
Clearly set the character set: Use the mysqli::set_charset method to set the character set to UTF-8.
Check the character sets of databases, data tables, and columns: Make sure the character sets of databases, data tables, and columns are set to UTF-8 (or the character set you need).
Check database configuration: Confirm whether the default character set is set to UTF-8 in the database server configuration file (such as my.cnf ).
$mysqli = new mysqli('localhost', 'username', 'password', 'database');
// 显式Set the character set to UTF-8
if (!$mysqli->set_charset("utf8")) {
printf("Error loading character set utf8: %s\n", $mysqli->error);
exit();
}
$charset = $mysqli->get_charset();
echo $charset->charset; // Should be displayed as utf8
When you use mysqli::get_charset , the returned character set is the character set used by the current database connection. If the character set is displayed as latin1 , it is likely that the character set is not set correctly during connection, or the character set settings of the database, data table, and columns are inconsistent. Make sure you set the correct character set when connecting to the database and check the character set configuration of the database and tables, which can help you solve this problem.
