What is preferable: an Enum or a singleton

I have the folowing question:

What is the prefered way to use the 开发者_Python百科status in code, an enum OR singleton?

I have in a DB stored the status values with their ID's. If the status changes in de DB is would also need some changes in the code.

does anyone now what is more prefered, based on conventions?

I've been looking on the internet but couldn't find a clear answer.

It depends in part on whether the ids for your statuses have guaranteed values, or whether the ids could change per-database (via an IDENTITY). Personally, for statuses I prefer fixed - which gives you the most flexibility, and least overhead - you can choose to use an enum (or maybe some consts if more convenient), and you never have to add an indirection, i.e. "get the id that is open".

This isn't always possible, though, and when it isn't it is still definitely useful to cache and re-use them (to avoid hitting the DB for that lookup). However, I would avoid a singleton, not least because it won't play nicely if you ever need to talk to more than one database - the ids in each could well be different. However, any suitable cache implementation (or maybe IoC/DI) should allow you to store the appropriate data (probably some kind of dictionary). Singletons are also just a bit of a pain generally if you like testing etc.

But: an enum and fixed id values is a lot simpler.

Note that under any implementation, changing the status list is a non-trivial operation, not least it will be a big UPDATE (or several if you are denormalized).

If you intend to use the Status across the application and is standardised across then it would be best fit for an Enum

Enum Status
{Open, Pending, Closed, Deferred}

Also this makes the code more readable