How to solve the problem of garbled characters when php reads data from the database

When using PHP to write a website or application, sometimes garbled characters appear when reading data from the database. This is a very common problem, but it is very annoying. In this article, we will explore the causes of garbled data when reading data from the database in PHP and how to fix it.

Cause of garbled characters

1. The database character set is inconsistent with the application

Transfer data between the application and the database If they use different character sets, the data will be garbled. For example, if the database uses the UTF-8 character set and the application uses the ISO-8859-1 character set, the data obtained from the database will be garbled.

2. The database connection character set is not set

If the database connection character set is not set, the server's character set will be used by default. If the character set of the server is inconsistent with the character set of the database, garbled characters will appear during data transmission.

3. Character set confusion in the database

Sometimes, the data saved in the database may be mixed character sets, such as UTF-8 and GBK encoding in the same field character of. In this case, garbled characters will appear when reading data.

Solution

1. Make sure the database character set and the application character set are consistent, and set them to the same character set.

In MySQL, you can change the database character set using the following command:

ALTER DATABASE database_name DEFAULT CHARACTER SET utf8;

For applications, you can set the character set to UTF-8 in PHP using the following command:

mysqli_set_charset($link, "utf8");

2. Set the character set when connecting to the database to ensure that the data transmitted between them uses the same character set.

In MySQL, you can set the character set when connecting to the database:

$link = mysqli_connect("localhost", "user", "password", "dbname");
mysqli_set_charset($link, "utf8");

3. Clean the data in the database, make sure they use the same character set, and save them all Convert to UTF-8.

Data in MySQL can be converted to UTF-8 using the following command:

ALTER TABLE table_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

Alternatively, text can be converted to UTF-8 in PHP using the following code:

$data = mb_convert_encoding($data, "UTF-8", "auto");

Conclusion

For the problem of garbled data read by PHP from the database, it may be that the character set is inconsistent during data transmission, the database connection character set is not set, or the character set in the database confusion. To avoid these problems, you can set the database and application to the same character set, and set the character set when connecting to the database. If garbled characters still appear, you can try cleaning up the data in the database and converting it all to UTF-8.

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