I’m going to offer a contrary opinion to most of the comments on this question. While EAV is EVIL for all of the reasons that you can find thoroughly explained many times here on SO and DBA.SE and elsewhere, there is one really common application for which most of the things that are wrong with … Read more
An EAV ‘database’ [sic] is literally mathematically straightforwardly an undocumented description in triples of a database and its metadata, with no functionality to tablulate relationships, or query relationships, or query metadata, or type check, or maintain integrity, or optimize, or transact atomically, or control concurrency. Software engineering principles dictate that sound EAV database [sic] use … Read more
The question mentions MySQL, and in fact this DBMS has a special function for this kind of problem: GROUP_CONCAT(expr). Take a look in the MySQL reference manual on group-by-functions. The function was added in MySQL version 4.1. You’ll be using GROUP BY FileID in the query. I’m not really sure about how you want the … Read more
There’s a few general pros and cons I can think of, there are situations where one is better than the other: Option 1, EAV Model: Pro: less time to design and develop a simple application Pro: new entities easy to add (might even be added by users?) Pro: “generic” interface components Con: complex code required … Read more