Error Mysql Said 1273 Unknown Collation Utf8mb4_unicode_ci Solusi

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May 08, 2025

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MySQL Error 1273: Unknown Collation utf8mb4_unicode_ci - Solutions and Explanations

Encountering the "MySQL Error 1273: Unknown collation utf8mb4_unicode_ci" can be frustrating, especially when you're working on a database-driven application. This error arises when MySQL doesn't recognize the utf8mb4_unicode_ci collation you've specified. Let's break down the problem and explore effective solutions.

Understanding the Error

The error message points to an incompatibility between the collation you're trying to use (utf8mb4_unicode_ci) and the MySQL server's available collations. This collation is a character set that supports a wide range of Unicode characters, including emojis and other non-Latin characters. The _ci suffix denotes "case-insensitive" comparison. The problem usually stems from a mismatch between your database's character set and the collation setting used for your tables or columns.

Troubleshooting Steps

Before jumping to solutions, let's systematically check your MySQL setup:

1. MySQL Version:

• Verify your MySQL version: utf8mb4_unicode_ci requires MySQL version 5.5.3 or higher. Use SELECT VERSION(); in your MySQL client to check. If your version is older, upgrading is necessary to support this collation.

2. Character Set and Collation:

• Database Character Set: Check the character set of your database using SHOW VARIABLES LIKE 'character_set_database';. It should be utf8mb4.
• Table Character Set and Collation: Examine the character set and collation of your tables. Use queries like:
  • SHOW CREATE TABLE your_table_name; to see the table definition, including character sets and collations.
  • SHOW TABLE STATUS LIKE 'your_table_name'; offers a summary view.
• Column Character Set and Collation: Inspect each column's character set and collation: DESCRIBE your_table_name; will show column details.

3. Fixing the Incompatibility:

If the character set and collation are mismatched or unsupported, follow these steps to rectify:

• ALTER TABLE statement: For existing tables, use ALTER TABLE statements to modify the character set and collation. For example:

  ALTER TABLE your_table_name
  CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
  

  Apply this to all relevant tables.

• CREATE TABLE statement: When creating new tables, explicitly define the character set and collation:

  CREATE TABLE new_table_name (
      id INT PRIMARY KEY,
      column1 VARCHAR(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci,
      column2 TEXT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
  );
  

4. Restarting the MySQL Server:

After making changes to character sets and collations, restart the MySQL server for these changes to take effect.

5. Checking for other collation issues:

• Check for conflicting collations: Ensure there aren't conflicting collation settings applied in different parts of your application.
• Check your application's code: Make sure that your application code doesn't override these settings.

Preventing Future Issues

• Consistent Character Set and Collation: Establish a consistent character set (utf8mb4) and collation (utf8mb4_unicode_ci) for all your databases, tables, and columns from the start.
• Database Design Best Practices: Good database design is crucial for avoiding these issues. Choose the appropriate data types and carefully plan your character sets and collations.

By carefully following these troubleshooting steps and preventive measures, you can effectively resolve the MySQL Error 1273 and ensure your database handles character data correctly. Remember to back up your database before making any significant changes. If problems persist, consult the MySQL documentation for your specific version for additional guidance.