4th Dimension - Creating A Bank Account Manager

By Ian Sharpe

In the first part of our Hands On series I show how to create a basic bank account tracker in 4D version 3.5, the full version of which was on last month's SuperCD. The design problems tackled in this issue are:

  • Customising the input form so that a blank Date field is primed with the current date.

  • Adding a button to the form which, when pressed, puts the date in the Date field.

  • Sorting the table view automatically after record entry and editing.

  • Automatic recalculation of account balances.

    • My ScreenCam tour explains how the application works and how it was constructed. A minimum of 800x600 resolution and 256 colours are needed. Click here to run it...

    Version 6 of 4D has a new look and many improvements over its predecessor. The new object-oriented interface conforms to the usual look of Windows 95 / NT4 programs. A richer feature set and greater ease of use are also in evidence. Version 6 is out on manoeuvres in the second ScreenCam, where I quickly build the same application. Click here to run it...

    Apart from the visual differences, one practical benefit quickly became apparent. When writing the script - now known as a method - the ability to turn off all event triggers other than form loading made the programming easier. Event triggers are like alarm calls. When certain things happen - events - they wake up a program written in 4D's own language. This takes over 4D and performs some function. When the program has finished, you continue using 4D as normal.

    Take the challenge...

    Scripts/methods are the key to extending applications beyond the standard features offered by 4D. While this series isn't about programming, 4D scripting will inevitably feature in it. If you want to use 4D to its maximum potential, you should aim to learn a little scripting yourself. After you've seen the ScreenCams and read the magazine article, why not accept Sharpie's challenge?

    In the first ScreenCam I said that an idea for the future is to have an error-check to ensure that one (and only one) of the Paid In and Paid Out fields has been filled in. Can you do it yourself? And what about making sure that the value is positive? No prizes - answer next month!