Should You Use MySQL's ENUM Type: A Cautionary Tale?

MySQL Enum Type: A Cautionary Tale

In database design, representing a finite set of options with integer values can seem convenient. However, this approach can become cumbersome, especially when the mapping to string descriptions is outsourced to a separate table.

MySQL's ENUM type appears to provide a more straightforward solution. However, it comes with its own pitfalls:

• Expensive Table Restructuring: Modifying an ENUM's value set requires an ALTER TABLE operation, which in certain cases can result in an expensive table restructure. Conversely, updating a lookup table is much simpler.
• Limited Attribute Support: ENUMs lack the ability to attach attributes to their values, such as retirement status or UI display eligibility. Lookup tables, however, can accommodate additional columns for such attributes.
• Challenging Distinct Value Retrieval: Retrieving all distinct ENUM values can be an arduous task, requiring complex queries involving INFORMATION_SCHEMA and BLOB parsing. Lookup tables, on the other hand, provide easy querying and sorting of values.

Due to these limitations, ENUMs may not be the ideal choice for scenarios where maintaining accurate mappings, flexibility in value sets, and efficient data retrieval are paramount. Instead, a lookup table approach may provide greater convenience and long-term reliability.

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