Common Interface Architecture
A common interface architecture focuses on providing a common API at the client side that enables access to multiple back-end databases. PRO-IV Client applications rely on the API to manage the heterogeneous data access issues discussed earlier. PRO-IV has native back end drivers that can be configured to obtain acces to a number of different databases.
Common Gateway Architecture
A common gateway architecture, relies on a gateway to manage the communication with multiple back-end databases. PRO-IV uses commonly available gateways and transport interfaces to allow access to multiple database sources.
In his book Introduction to Database Systems, C.J.Date states “……… there are clearly significant problems involved in providing satisfactory gateways, especially if the target system is not relational. However, the potential payoff is dramatic, even if the solutions are less than perfect. We can therefore expect to see gateway technology become a major force in the marketplace over the next few years”2 (page 635).
PRO-IV support for Common Protocol Architecture
The common protocol approach, focuses on a common data protocol between the client and server interfaces. Conceptually, this is perhaps the most elegant way of addressing the problem of heterogeneous data access. Two common data protocol architectures are the proposed ANSI/ISO Relational Data Access (RDA) standard, and the IBM. Distributed Relational Database Architecture (DRDA). Both of these architectures are in their infancy, and it is too early to determine how well they will function as commercial products.
PRO-IV today supplies you with native access protocols that are specifically tuned to each database for the best performacne you can get. When a common acces standard emerges that provides sufficient performance, PRO-IV will support this standard. PRO-IV Life Cycle Support Sometimes you hear a supervisor asking a programmer ‘When will that program be finished?’ Programs are never finished, application systems are never completed… until they are replaced. Programs don’t have moving parts which wear – they work until their underlying design no longer mirrors the real world or until their life support systems are turned off. When you set out to develop computer based solutions for business it is important to understand how the tools you choose to develop them will support the future changes both in the business and the in delivery technologies. Today the traditional ‘waterfall’ picture of large scale system development, and the replacement of whole application systems over a three or five year lifecycle is no longer an appropriate model except for the largest of institutions (or those with more money than sense!). We live in a world of fast changing requirements where RAD, design flexibility and delivery across multiple computer environments are expected without compromising either raw performance or the quality of the delivered system. PRO-IV Case Tool Integration You can successfully prototype interfaces and processes but not data structures. One of the lessons of the last twenty years has been that data structures must be decoupled from the high level processes that use them. Information has an ownership separate from the ownership of the routines which update or retrieve it. These days a multiplicity of products are manipulating and extracting information from the desktop or across remote links. Automated tools for managing the database design and performing automated normalization, level balancing and validation are a critical part of developing an application. This is a co-operative exercise so this means support for multiple developers working on a common repository. PRO-IV supports a closely integrated CASE tool to support the development, validation, modeling and diagramming requirements of business system analysis. Information from this central repository can be shared with the applications development dictionary.
It is often easy to relate to diagrams when designing systems, for showing boundaries, process flow or data structures. PRO-IV Workbench for Windows has extensive diagramming capabilities. These are based on co-operative development with a single design repository which allows changes made by others to be automatically updated on an on screen diagram, for example. PRO-IV Workbench for Windows supports very large models and a zoom facility which also provides an on-screen context map showing your overall position in the whole diagram when you are examining a small portion of it.