I have many tables that use Lookup/Enum references for most of their column values.
For example:
Person Table – PersonID | RaceCode | HairColorCode | HairStyleCode | TeethConditionCode
Location Table – LocationID | SizeCode | ExteriorColorCode | ConditionCode
Things like Race,Size,Color,Condition,etc would just be foreign key references to a Code lookup table. This code table has other fields but aren’t important for my question. The database is for a SaaS application which means each client could have their own list of of Colors, Races, Conditions, etc. There are some codes that would be static which clients couldnt change.
Is it better to have 1 code table or 2 types of code tables (DynamicCodeTable for customer defined ones and StaticCodeTable for those that one change) or should I have a table for each code type (RaceCodeTable, HairColorTable, Condition, etc) ?
The thing I am the most worried about is all the sql joins. The Person table I am working with has 20+ of these code attributes. Is there a difference in performance when joining to 20 different tables VS joining to the same table 20 times? Having multiple tables means each table would be smaller and the lookup ‘should’ take less time. But having a single table could be quick too. Any suggestions?
Without knowing more about the application or requirements I would recommend having one table for each code type. IMO the database design would be more clear and self documenting to have foreign keys for each type of code you have.