utf8_general_ci vs. utf8_unicode_ci: Which MySQL Collation Should You Choose?

Understanding the Difference between utf8_general_ci and utf8_unicode_ci

utf8_general_ci versus utf8_unicode_ci: A Definition

In MySQL, the choice between utf8_general_ci and utf8_unicode_ci collations can significantly impact the performance and accuracy of your database queries.

utf8_general_ci: Converts text to Unicode normalization form D, removes combining characters, and converts to upper case. This approach fails to handle Unicode casing accurately.

utf8_unicode_ci: Utilizes the standard Unicode Collation Algorithm, providing support for expansions and ligatures, resulting in more accurate sorting.

Implications for Database Design

Accuracy:

• utf8_general_ci yields incorrect results on Unicode text due to its simplistic approach.
• utf8_unicode_ci ensures precision for diverse scripts, such as Cyrillic and Greek, by adhering to the Unicode Collation Algorithm.

Sorting:

• utf8_general_ci treats expansions and ligatures as separate characters, leading to improper sorting.
• utf8_unicode_ci appropriately sorts these special characters within their respective language contexts.

Linguistic Support:

• utf8_general_ci provides language-specific support primarily for Russian and Bulgarian.
• utf8_unicode_ci extends support to a wider range of languages, including Belarusian, Macedonian, Serbian, and Ukrainian.

Performance:

• utf8_unicode_ci may slightly decrease query speed compared to utf8_general_ci.

Choosing the Right Collation

Consider these factors when selecting a collation:

• Accuracy is paramount, so avoid utf8_general_ci unless incorrect sorting is acceptable.
• Opt for utf8_unicode_ci for a robust and language-agnostic solution.
• For general databases that prioritize speed, utf8_general_ci may suffice.
• For databases requiring language-specific sorting accuracy, utf8_unicode_ci is essential.

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