Introducing Table-Valued Parameters - Part 1

dpblogs — Sat, 16 Aug 2008 02:37:53 GMT

Hey everyone!

I am Himanshu. I am a program manager in the ADO.Net team. Today I am going to talk about Table-Valued parameters that are new in SQL Server 2008. About 4 years back I was writing an application which involved adding metadata about my music library into a database. The database had a table each for storing Artists, Albums, and Songs. While adding an Album of songs into the database I had to insert data into each of these tables. I had defined stored procedure for inserting data into each of the tables. In the first iteration there was a bug in the code due to which these operations were not being done in a single transaction. Needless to say this bug surfaced as a data-corruption issue later on. Once identified the fix was trivial, ensure that all commands are executed in a single transaction. However, what I would have really liked to do was to be able to call a single stored procedure to which I could pass the metadata about the Album and the list of songs at the same time. But there was no good way of accomplishing this back then. I was programming against SQL Server 2000 back then. I am excited to say that now with the new table-valued parameters in SQL Server 2008 I can finally write a single stored procedure that will let me accomplish this without any kind of hacks!

Table-Valued parameters, as the name suggests lets you pass a table as parameter to a stored procedure. In order to use table-valued parameters you need to define a table type and then use the table type in the definition of the stored procedure. Let me illustrate this with the help of an example. I am going to first create a table type named Songs_TableType with two columns, Title and TrackNumber. Then I will use it in a stored procedure to pass a table as parameter.

First creating the table type

Create Type Songs_TableType as Table
(Title nvarchar(120) not null,
TrackNumber int)

I can now use this type in a stored procedure to pass a table as a parameter. The following T-Sql shows how to define a stored procedure that takes this type as a parameter. Note that I have skipped error handling for brevity.

create procedure AddSongs(
 @ArtistName nvarchar(120), 
 @AlbumName nvarchar(120), 
 @Songs Songs_TableType READONLY)
as
begin
 -- Add the Artist
 Declare @ArtistID int
 insert into Artists values (@ArtistName)
 select @ArtistID = SCOPE_IDENTITY()

 -- Add the Album
 Declare @AlbumID int
 insert into Albums values (@AlbumName, @ArtistID)
 select @AlbumID = SCOPE_IDENTITY()

 -- Insert songs
 insert into Songs 
 select title, trackNumber, @AlbumID, @ArtistID
 from @Songs
end

In the next post I will go into more details into how I can use the stored procedure defined above to simplify the code I have on the client. Till then, adios!

Himanshu Vasishth
Program Manager
ADO.NET

Connecting to Pre-Release Versions of SQL Server 2008 – Part Deux

dpblogs — Mon, 07 Apr 2008 21:24:00 GMT

Since posting on the topic of design-time and runtime connectivity to pre-release versions of SQL Server 2008 on the Data blog in November, the set of affected clients (applications, runtimes, and operating systems) have been officially released: Microsoft Visual Studio 2008, Microsoft .NET Framework v3.5, Microsoft Vista Service Pack 1, and Microsoft Windows 2008. Runtime connectivity from a client system configured with any of these released products to SQL Server 2008 November CTP or later provides full runtime access to the following features (for design-time functionality, see below):

· Table-Valued Parameters

· New date/time data types

· Large user-defined types

· Support for very large FILESTREAM-attributed column data

Design-Time Connectivity Between Visual Studio and SQL Server 2008

Developers using Visual Studio 2005 or Visual Studio 2008 design tools will receive an error when trying to open a database on any pre-release instance of SQL Server 2008 without installing a Visual Studio patch. Pre-release patches for Visual Studio 2008 and Visual Studio 2005 enable the following Visual Studio functionality for SQL Server 2008:

· Server Explorer successfully connects to SQL Server 2008, and database objects such as stored procedures and table data can be viewed and edited.

o Note that table schemas still cannot be viewed or edited in this release.

· SQL CLR projects that target SQL Server 2008 can be created and deployed to the server.

· T-SQL and SQL CLR debugging are now enabled for SQL Server 2008.

· Data binding features in Client and Web Projects are enabled.

Pre-release versions of the design-time patches are currently available: the Visual Studio 2008 CTP patch is available for download here and the Visual Studio 2005 CTP patch is available for download here. Final versions of the patches will be available in the near future. For more information please see the "Connecting to Microsoft SQL Server 2008 from Microsoft Visual Studio 2005 and 2008" whitepaper on MSDN.

Debra Dove

Program Manager Lead, Data Programmability

ADO.NET team blog : SQL Server 2008

Introducing Table-Valued Parameters - Part 1

Connecting to Pre-Release Versions of SQL Server 2008 – Part Deux