Are there any benefits to using sql_variant over varchar in SQL Server?

Question

I currently have a database table setup as follows (EAV - business reasons are valid):

• Id - int (PK)
• Key - unique, varchar(15)
• Value - varchar(10

Answer 1

The good thing about sql variant is that you can store several types in a column and you keep the type information.

Insert into MySettings values ('Name','MyName'); Insert into MySettings values ('ShouesNumber',45); Insert into MySettings values ('MyDouble',31.32);

If you want to retrieve the type:

select SQL_VARIANT_PROPERTY ( value , 'BaseType' ) as DataType,* from mysettings

and you have:

Datatype Name          Value
-----------------------------
varchar  Name          MyName
int      ShoesNumber   45
numeric  MyDouble      31.32

Unfortunately this has several drawbacks:

1. not very fast
2. not well supported by ORM frameworks