CLR Assembly C# inside SQL Server

Question

• Is it possible to make a big project in C# (lots of functions), then,
• Create CLR Assembly for it, then,
• In SQL Server IN A STORED PROC, call a function that is in the assembly,

• The table (which I would pass to ASSEMBLY) is computed in other stored proc...

  • If so, What would be the steps?

I am thinking something like this.

-- I have a stored proc that gets a table, let it be myStoredProcTable

--FIST ENABLE DATA ACCESS
EXEC sp_serveroption 'TheServerName', 'DATA ACCESS', TRUE

--main.sql calls yStoredProcTable.sql and the calls functionAssembly
SELECT  *
INTO    #tmpTable
FROM    OPENQUERY(SERVERNAME, 'EXEC test.dbo.myStoredProcTable 1')


-- pass the table to assembly
-- how would i pass the table to assembly code?, Is this POSSIBLE?
    EXEC functionAssembly #tmpTable

------------------------------------------edit

Following @faester answer: - How could I use XML in the code, I suggested to use the numberTOstring thing, but I guess XML option is the best here...

Again, I really do this, even if is not the best choice...

Answer 1

Yes you can register assemblies, but it is rarely a good idea due to performance issues.

But if you make complex numeric calculations or similar operations on scalar values it can give you a lot of flexibility. But the problem remains that SQL is natively set oriented which C# isn't, so you will easily run into mismatches.

You should also be aware that you can only import static members on static classes.

But an example This class - which intentionally doesn't have a namespace since it seems to be impossible to import classes in a namespace.

    public static class Math
    {
        [Microsoft.SqlServer.Server.SqlFunction]
        public static int Add(int a, int b)
        {
            return a + b;
        }


        [Microsoft.SqlServer.Server.SqlProcedure]
        public static void Void(int a, int b)
        {
        }
    }

It takes some SQL to get the server ready and you probably need to be admin.

    EXEC SP_CONFIGURE 'clr enabled', 1
    GO
    RECONFIGURE
    GO
    -- CONSIDER: DROP ASSEMBLY SqlClr
    GO
    CREATE ASSEMBLY SqlClr 
    FROM 'pathtoassembly'
    WITH PERMISSION_SET = SAFE;
    GO
    SELECT * FROM sys.assemblies
    GO
    CREATE FUNCTION [MathAdd] (@a int, @b int)
    RETURNS INT 
    AS EXTERNAL NAME [SqlClr].Math.[Add]
    GO 
    CREATE PROCEDURE [Void] @a INT, @b INT
    AS EXTERNAL NAME [SqlClr].Math.[Void]
    GO 
    SELECT dbo.MathAdd (1, 2)
    EXEC void 1, 2

AGAIN: You really should be confident that you need this, it is rarely a good idea! (I have used it once for email validation making dns lookups etc, but that was on a system where all business logics was written in SQL. And that is bad!)

Some useful references:

http://msdn.microsoft.com/en-us/library/ms189524.aspx

http://www.codeproject.com/KB/database/CLR_in_Sql_Server_2005.aspx

Answer 2

Use the SQL CLR to perform the exact function you described.