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A comment on Cost of a Join. Parent comment

Re:Cost of a Join by donarb on Tuesday August 14, 2018 @06:47PM (#17762569)
enum does exist in PostgreSQL (which is in the article's URL). But an enum still requires a lookup for the associated value when setting and getting rows, it's not free.
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Re:Cost of a Join by jjeaff on Tuesday August 14, 2018 @07:01PM (#17762647)
It's got to be way closer to free than a separate table join.

But I did find a good answer hear about the pitfalls of enum in MySQL. Some/most of which would apply in the case of PostgreSQL.

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Re:Cost of a Join by TylerE on Tuesday August 14, 2018 @09:14PM (#17763163)
Postgres joins against small tables are really really efficient. It wouldn't shock me if enums actually were implemented as tables.
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