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By Albert D. Kallal
Friday, April 06, 2001
Notes on Conversion of a Pick (Multi-Value database) Application to a Relational database system.
Albert D. Kallal
Copyright, April, 2001
Notes: - (this is a unfinished draft on conversion of a Tour Reservation system from Pick to ms-access).
This document assumes that the reader is familiar with a MV (multi-value) database. The MV data model has many advantages over a traditional relational database. The most obvious advantage is that a record consists of multiple tables. The advantages in this type of data model for real world data is a topic too involved for this document. What follows is some notes and observations on conversion of a Pick application to a traditional relational system. Pick (now Omnis)
I freely use the term VB, and Ms-Access interchangeably through out this document. When I use the term Access, or VB, I am talking about MS-access (I used ONE product here). Since the programming language used in Ms-Access is VB, then one might as well consider Ms-Access a VB programming environment. Most people who refer to the pick system are also referring to the environment. This includes Mv-Basic and Recall/Access (a query language similar to SQL), TCL, and hopefully some type of application development tool (such as System Builder).
Ms-access is much better then just VB alone for database applications. Current experienced developers rate development speed in Ms-Access at least 2-3 times that of VB (some who I have high respect for rate it as high as 10x). The event model, and report writer are far better then what programmers use in VB. There has been some recent debate that the new Access (a2000) does damage programmer productivity by a fair amount when compared to a97. This project was developed in a97 for this very reason. When done, it will be converted to a2000. The new version of a2002 does apparently address this loss of productivity, and the speed of saved has improved (thus restoring precious developer time).
Ms-Access is one of the best RAD tools around. Combined with the built in VB (usually referred to VBA) it is a very powerful tool. The learning curve for VBA is somewhat steeper than VB is due to the richer event model. In addition there is the requirement to understand the application "object" model. While many people use Access without knowing or using VB, a understanding of the Access object is required for any serious development work.