if NOT EXISTS(SELECT * FROM sys.columns 
    WHERE Object_ID = Object_ID(N'pal_Surface') AND Name = N'linkUser')
BEGIN
ALTER TABLE [dbo].[pal_Surface]
    ADD [linkUser] BIT NULL;
END

if NOT EXISTS(SELECT * FROM sys.columns 
    WHERE Object_ID = Object_ID(N'pal_SurfaceItem') AND Name = N'userLink')
BEGIN
ALTER TABLE [dbo].[pal_SurfaceItem]
    ADD [userLink] INT NULL;
END

