Saving Abstract and Sub classes to database

I have an abstract class "StrategyBase", and a set of sub classes, StrategyA/B/C etc. The sub classes use some of the properties of the base class, and have some individual properties. My question is how to save this to a database.

I'm currently using SqlCE, and Linq-To-Sql by creating entity classes automatically with SqlMetal.exe. I've seen there are three solutions shown in this question, but I'm not able to see how these solutions will work or not with SqlMetal/entity classes. Though it seems to me the "concrete table inheritance" would probably work without any manual modifying. What about the other two, would they be problematic?

For "Single Table Inheritance" wouldn't all classes get all variables, even though they don't need them? And for the "Class table inheritance" solution I can't really see at all how that will map into the entity-classes for a useful purpose. I may note that I extend these partial e开发者_开发问答ntity classes for making the classes of my business objects.

I may also consider moving to EntityFramework instead of SqlMetal/Linq2Sql, so would be nice also to know if that makes any difference to what schema is easy to implement.

One likely important thing to note is that I will constantly be develop new strategies, which makes me have to modify the program code, and probably the database shcema; when adding a new strategy.

Sorry the question is a bit "all over the place", but hopefully it's some clear advantages/disadvantages here that you may be able to advice. ?

Cheers!

Actually, this exact question gets asked an awful lot, and has been answered many times. You probably have not searched using database terminology.

The problem is applying OO terminology and thinking in a non-object subject area; making an ordinary straight-forward task very complex and limited.

Martin Fowler's and Scott Ambler's books are not worth a dollar for the lot of them, details in this answer, starting at the 11 Dec 10 entry.

If you still have questions, post a comment.

One option would be to make StrategyBase Serializable, then you can store it as a string in the database. I don't know how big the string would be, as it all depends on the size of your object, but you can make the database field nvarchar(1024) or even nvarchar(max). Ultimately this would result in the entire object being stored in a single table field as string.

Alternatively, as your link eludes to, you can just make a table that mimics each class, and each class object is a field in the table.