Publications Details

Picking columns at run time

Vopicka, D.

I was asked to write a database application that would be user friendly to the extent that a minimum amount of learning would be required of the user to run the application, yet it would be flexible enough to gather the data in various combinations. Writing SELECT'' or RETRIEVE'' queries required to much initial training. Hard coding queries into the application meant the users could not pick columns or create contraints. I decided to compromise somewhat, requiring my users to learn how to manipulate VIFRED menus and by doing so they could pick any combination of columns for output, select any column variable to sort on, and impose simple, yet practical constaints on the data, all this possible at run time. This handout contains copies of the VIFRED menus, the help message for imposing constraints, output from sample retrievals, descriptions of the relational tables needed to implement the methodology, and the computer coding of the actual retrieval construction.