The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 2: Getting Started with FILESTREAMIf the table already has a UNIQUEIDENTIFIER column with all the required characteristics,you can simply go ahead and add the FILESTREAM column using the ALTERTABLE script in Listing 2-9. However, if the table does not have a UNIQUEIDENTIFIERcolumn then you need to add one, with all the required attributes. Listing 2-11 shows howto do this.ALTER TABLE [dbo].[Items]ADD ItemID UNIQUEIDENTIFIER ROWGUIDCOL NOT NULL UNIQUEGOListing 2-11:Adding a UNIQUEIDENTIFIER column with all the required attributes.A third possible outcome is that the table already has a UNIQUEIDENTIFIER column, butit does not have all the required attributes. For example, the column may allow NULLS,or it may not be marked as a ROWGUIDCOL, and so on. Depending upon your designrequirements, you could either add a new column with the required attributes, as shownin Listing 2-11, or you could change the existing column, as shown in Listing 2-12; note,though, that a table can have only one ROWGUIDCOL.-- Create a table with a UNIQUEIDENTIFIER ColumnCREATE TABLE [dbo].[Items]([ItemID] UNIQUEIDENTIFIER ,[ItemNumber] VARCHAR(20) ,[ItemDescription] VARCHAR(50))-- Alter the UNIQUEIDENTIFIER column to NOT NULLALTER TABLE ItemsALTER COLUMN ItemID UNIQUEIDENTIFIER NOT NULL-- Add a UNIQUE ConstraintALTER TABLE ItemsADD CONSTRAINT IX_ItemID UNIQUE(ItemID)-- Create a ROWGUIDCOLALTER TABLE ItemsALTER COLUMN ItemID ADD ROWGUIDCOL65