what data might be needed for a routine/structured decision such as a sales or purchasing or payroll summary?
what data might be needed for a routine/structured decision such as a sales or purchasing or payroll summary?
That is a very open ended question with no clear answer. If you have a structured way of doing business, for instance if your stock falls below X you want to order Y more, you're talking about an inventory management type of database. If you're talking about applying taxes to payroll earnings and accounting for time off/vacation days/sick days that's another problem entirely. If you're trying to build a comprehensive application for your business start with the most important piece first, get that working, then move on to the other parts.
Have you tried to create a flow chart or decision tree or a series of facts in plain simple English?
I think you should pose a question(s) regarding one of your subjects (sales or purchasing or payroll), and then work from that.
Some of the parameters would include:
Who, what, where, when, why, how and how often
Some reading:
http://en.wikipedia.org/wiki/Decision_tree
http://en.wikipedia.org/wiki/Truth_table
I think we need more context to give a more focused response.