USP_PATTERNBLOCK_UNUSED_DELETE

            CREATE procedure [dbo].[USP_PATTERNBLOCK_UNUSED_DELETE]
            (
                @CHANGEAGENTID UNIQUEIDENTIFIER=NULL
            )
            as begin
                set nocount on

                declare @contextCache varbinary(128)

                /* cache current context information */
                set @contextCache = CONTEXT_INFO()

                /* set CONTEXT_INFO to @CHANGEAGENTID */
                if not @CHANGEAGENTID is null
                    set CONTEXT_INFO @CHANGEAGENTID

                delete
                    PATTERNBLOCK
                where
                    not exists(select id 
                               from PATTERNBLOCKMEETING 
                               where PATTERNBLOCKMEETING.PATTERNBLOCKID = PATTERNBLOCK.ID)

                /* reset CONTEXT_INFO to previous value */
                if not @contextCache is null
                    set CONTEXT_INFO @contextCache

                return 0
            end