The problem of database garbled code is usually caused by inconsistent proofreading rules. The solution is to ensure that the proofreading rules of the database, table, column and connection layer are consistent. 1. The server-level default settings should specify utf8mb4 in the MySQL configuration file; 2. Select utf8mb4_unicode_ci when creating or modifying the database; 3. Use utf8mb4_unicode_ci when creating or converting tables; 4. Modify the character set of specific columns if necessary; 5. Set the character set to utf8mb4 immediately after applying the connection; 6. Ensure that the file uses UTF-8 encoding when importing and exporting. These steps can effectively prevent abnormal display problems.

When working with databases through phpMyAdmin, one of the most common yet overlooked aspects is collation settings. If you're seeing weird characters, question marks, or garbled in your data, chances are it's a collation mismatch somewhere along the line. The key to avoiding display issues lies in ensuring consistency across the database, tables, columns, and even the connection level.

Understand What Collation Means

Collation determines how string data is sorted and compared. More importantly for everyday use, it also affects how characters are stored and retrieved. UTF-8 (or its newer variant UTF8MB4) is the standard encoding that supports most modern languages ??and emojis.

• UTF8MB4 is preferred over UTF8 in MySQL because it supports 4-byte characters like emojis.
• Common collations include utf8mb4_unicode_ci , utf8mb4_general_ci , and regional ones like utf8mb4_spanish_ci .

Mismatched collations at different levels—server, database, table, column—can cause inconsistent behavior, especially when dealing with multilingual content or imported data.

Set Consistent Collation at Every Level

To prevent character issues, make sure all these layers use compatible collations:

Server-Level Default

This is usually set in the MySQL configuration file ( my.cnf or my.ini ). While not always under your control via phpMyAdmin, it's good to know what the default is.

Database-Level Default

When creating a new database:

1. In phpMyAdmin, go to the "Databases" tab.
2. Enter a name and choose utf8mb4_unicode_ci (or similar) from the collation dropdown.
3. Create the database.

Existing databases can be altered:

 ALTER DATABASE your_db CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Table-Level Default

When creating a table, specify the collation:

 CREATE TABLE example (
    id INT PRIMARY KEY,
    text VARCHAR(255)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

For existing tables:

 ALTER TABLE your_table CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Column-Level Settings

Sometimes individual columns might have different collations. Check them in phpMyAdmin by browsing the table structure. You can alter specific columns if needed:

 ALTER TABLE your_table MODIFY column_name VARCHAR(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Don't Forget the Connection Layer

Even if everything else is set correctly, if your application doesn't communicate using the correct character set, you'll still get garbled text.

After connecting to the database (via PHP, for example), run:

 mysqli_set_charset($connection, "utf8mb4");

Or execute:

 SET NAMES 'utf8mb4';

If you're using PDO:

 $pdo = new PDO("mysql:host=localhost;charset=utf8mb4", "user", "password");

Make sure this runs early in your script before any queries.

Double-Check Import/Export Procedures

When importing SQL files or migrating databases:

• Ensure the dump was created with the right character set.
• Use the “Character set of the file” option in phpMyAdmin during import and select utf8mb4 .

Also, check the file encoding if you're editing SQL dumps manually—it should be UTF-8 without BOM.

That's basically it. Managing collation through phpMyAdmin isn't complicated, but it does require attention to detail across multiple layers. Most problems come from mismatched settings or forgetting the connection charset, so double-check those areas first when things go wrong.

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