C#: How would you store arbitrary objects in an SQL Server?

Question

Lets say you have various objects of arbitrary type that you would like to store in a key+value type of table. Key could for example be an int, string or guid. What would th

Answer 1

Usually I use a specific column for a certain kind of value.

Eg.

• Guid: UNIQUEIDENTIFIER
• numbers like int, decimal, byte etc: DECIMAL
• string: NVARCHAR
• DateTime: DATETIME

I'm using NHibernate, there it is very easy to have a subclass for each specific type and map them to the same table, each using a specific field for its specific value. I get a table like this:

create table dbo.Value (
  Name NVARCHAR(80) not null,
  Type NVARCHAR(6) not null,
  TextValue NVARCHAR(500) null,
  GuidValue UNIQUEIDENTIFIER null,
  NumericValue DECIMAL(36, 18) null,
  DateTimeValue DATETIME null
)

The column Type is either 'TEXT', 'GUID', 'NUMBER' or 'DATE'. This is all done by NHibernate, but can easily be used and manipulated without it.

Additionally you could store a reference to another entity by using an NH any type as value (storing a primary key and an entity name).