The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 4: FILESTREAM with Entity Framework and LINQ to SQLThe stored procedure takes three arguments that are mapped directly to fields in theItems table. There is no input parameter for the ItemImage field because we provide adefault dummy value of 0x (zero-length binary value). This ensures that a FILESTREAMdata file will be created for the new record, but the file is a zero-length (empty) file.We also select the value of the SCOPE_IDENTITY() function as a new field with nameNewItemID. Because ItemID is an IDENTITY column, we will use the value of that fieldto update the ItemID scalar property value of the stored Item object instance with thevalue assigned by the database engine.The second new stored procedure, GetSqlFileStreamInfo (Listing 4-7), will return thevalues necessary to create a SqlFileStream object instance for the FILESTREAM dataof a given item (identified by the ItemID parameter). The stored procedure will returna single row containing the path name of the FILESTREAM data file, the transactioncontext of a previously started transaction and the length of the FILESTREAM data file.CREATE PROCEDURE [dbo].[GetSqlFileStreamInfo]@ItemID intASBEGIN-- SET NOCOUNT ON added to prevent extra result sets from-- interfering with SELECT statements.SET NOCOUNT ON;END-- Insert statements for procedure hereSELECT I.ItemImage.PathName() AS FilePath,GET_FILESTREAM_TRANSACTION_CONTEXT() AS "Context",DATALENGTH(I.ItemImage) AS "Size"FROM Items IWHERE I.ItemID = @ItemIDListing 4-7:Creating a stored procedure to retrieve the SqlFileStream constructor values.145