SOFTware is HARD

This is a sample of a use case realisation ( design-level ) for a use case “ View the Dashboard ”. The implementation uses ASP.NET MVC and the design is documented in the following UML diagrams. This is an experiment whereby I produced the design in UML for a new developer to implement the use case. The following Sequence Diagram documents the initial web request to display the empty Dashboard. The following Sequence Diagram documents subsequent web requests to display the search result. The next Sequence Diagram specifies the implementation of DashBoardCntrl::retrievePlanListFromCache . The final is the View-Of-Participating-Class (VOPC) diagram for this use case realisation.

A sequence number or an identity column guarantees the following: Number served is unique. Number served is sequential (ascending order) - Identity columns guarantees this; sequence number in Oracle RAC mode doesn't, unless ORDER is used. However: It does not guarantee the sequence is gap-free Sequence number/ identity columns do not partake in transactions Number loss/ gaps happen due to the following: Served number does not get utilised (typically due to transaction rollback) Server restart/ failures - database servers tend to cache sequences in memory for performance reasons. E.g. Oracle Sequence number set-up to be CACHEd in memory. According to Oracle 11gR2 Database Documentation : for the Sequence database concept, use of Oracle Sequence does not guarantee gap-free set of numbers.   If your application requires a gap-free set of numbers, then you cannot use Oracle sequences . You must serialize activities in the database using your own developed cod

An appreciation to why people are dishonest. Flash version can be found here .