Lookup Tables Best Practices: DB Tables… or Enumerations

Question

If we have to store the available positions at a company (i.e. Manager, Team Lead, ... etc). What are the best practices for storing it? I have two opinions with comments...

Answer 1

Generally you should only use enumeration where there is a clear set of items that will not change, e.g. primary colours, or continent names. Otherwise lookup tables with appropriately implemented foreign keys are pretty much always the best option.

There is a possible variation on the lookup table option where you potentially have a large number of lookup tables for simple id/value relationships. A domain/lookup table pair can dramatically reduce this the number of tables required, albeit with some additional coding complexity. In this case you'd have a domain table

DomainID int identity
Domain   varchar(255)

and a key/value table

DomainID int
ID       int identity
Value    varchar(255)

Hence a row is added to the Domain table corresponding to each lookup table that you would otherwise use, and all (key-domain)/value pairs added to the value table. Apart from simplifying the database structure this approach also has the advantage that 'lookup tables' can be created in the application code dynamically, which in some applications can be extremely useful.

Answer 2

Is the only thing you are planning on putting into a db this list of employers?

If yes, drop it in a file, and be done with it.

DBs are great, but if you need a simple key-value, they are overkill. They give you a lot of stuff. But they also do a lot of stuff behind the scenes, they are one more thing you need to support... if you can get away with a single file with 20 tab-delimited lines, go with simplicity.

If you have a lot of things that require these kinds of lookups, or if you think you might need to update them while a client is trying to read them, or if you might want to cross-reference things later on -- then go for the DB.

Answer 3

I generally prefer both. I use table in the dal layer as they can be used for tools like tableau for reporting, SQL queries and other purpose.

I use enums in the front end and the business layer because its easy to develop with them and you dont have to get the list from the dal neither you have to remember the values from the table.

C# automatically convert the enums to corresponding ID for you if the list is same in the table and the enum.

In MVC you can use the dropdown with the enums as @Html.EnumDropdownListFor() in the View so you dont have to the hit the database itself for dropdowns.