Category Archives: Programming

How to Convert Between Roman and Arabic Numerals in C#

The Challenge

My latest challenge to my database programming students was to create a C# class that would perform various number conversions, starting with Arabic numbers (0 to 3999) to Roman numerals and vice versa.

I required that all public functions in the class needed to be declared as static, so that they could be called from outside the class without having to create a new instance. Also, the class was to be completely portable;  it must not use any functions such as message boxes that would prevent them from copying the entire class into any other type of project and referencing it.  Of course, all code must also have error handling and commenting.

My students came up with various solutions and I think some had more help from StackOverflow than others.  I know that one of them learned the hard way not to search for “XXX” on Google.

One popular strategy was to use the C# Dictionary class to hold the Roman characters and their equivalents.  I don’t always get around to writing up my own solutions to these challenges before I assign them, so I happily swiped that strategy for my own code which was otherwise written from scratch. I ended up using the SortedDictionary class instead.

Continue reading

How to Create Lookup Fields in C#

I started my (more or less) serious database development training many years ago in Microsoft Access.  One of my favorite controls was the Combo Box, a nice little drop-down field that enabled the user to select one of many values but collapsed down onto a single line.  The Combo Box control in Access was very configurable and one of the nice features was that  you could display one value while actually saving another value to the field the control was bound to.  For example, you could display the Customer Name while saving the associated CustomerID that the database would use to reference the customer record.

C# also has a Combo Box control that can do much the same thing but offers a lot more options through code.  The .NET version maintains a collection of objects, any kind of objects, and displays whatever text is presented by the object’s ToString() method.   The code can then use any other property of the object to carry out operations in the background.

Continue reading

How to Retrieve Data from SQL Server into C#

The .NET framework has a few different automated methods for managing connections to SQL Server and other databases. The framework has been around since 2003 and various versions have introduced new, improved data management tools while maintaining the old ones for backward compatibility.

It’s still possible, however to retrieve data from SQL Server and other database systems with just a few lines of code and it’s important to know how to do this to truly understand how the communication between SQL Server and a language like C# actually works.

Continue reading

How to Convert Between Decimal and Binary in T-SQL

For the past six months, I’ve been teaching night classes in database programming and my students are just about ready to take Microsoft’s 98-364 exam. Now, we’re transitioning over to C# programming for the next phase of the program but I have to keep their SQL skills fresh for the exam.  Tonight, it was time to teach them to understand the binary number system.  I dropped some hints on it a couple of months back to brace them but now it was time to get it done with once and for all.

Then, as I like to do with this class, I came up with a lesson plan that would incorporate the best of both subjects …

Continue reading

Primes in the Key of C#

Yes, prime numbers are a go-to challenge for me that I’ve been casually playing with since my earliest programming days. I’m not alone; prime numbers are important and popular enough that there’s an entire distributed computing project dedicated to finding the highest Mersenne Prime number (primes such as 31 and 127 that are one less than a power of 2). A decent grounding in math is also important for programmers and prime number algorithms are a much better programming exercise than “Hello, World”.

That’s why, during a holiday trip to a local Barnes & Noble, I was looking through their collection of quick and shallow knowledge books (“100 Factoids That Will Make You Sound Knowledgeable  …” ) and found one called Math Squared: 100 Concepts You Should Know. I wasn’t expecting a degree out of this small, 256-page book but it’s been awhile since math class, I thought it might give me some good ideas for programming exercises and I like the feel and smell of new books.
Continue reading

My First Steps with Python – Prime Numbers

I recently started studying the Python programming language. I’m getting ready for a new programming-related position next year and one of my colleagues suggested using Python as part of it. I’ve heard of Python more and more over the past several years and I figured now would be as good a time as any to finally learn it.

I can definitely recommend Udemy’s Complete Python Bootcamp by Jose Portilla. This course is written for complete programming beginners and does an excellent job of introducing the fundamentals and guiding the student through various programming concepts. It’s probably more basic than I actually need but it never hurts to go back to school.

Continue reading

Power Up! Weekend – Ocala’s First Hackathon

Ocala’s Chamber and Economic Partnership (CEP) and the Ocala I.T. Professionals are sponsoring Ocala’s first hackathon at the Power Plant Business Incubator on October 15 & 16, 2016!  For complete details and to register, visit http://powerupweekend.eventbrite.com. Attendance is limited to the first 100 people registered so be sure to sign up early!

Both days will start at 10 a.m.. Attendees are welcome to stay until 10 p.m. on the first day when we’ll be forming teams and beginning to code. The event will wrap up at 5 p.m. on Sunday, Oct 16, when each team will present what they’ve made.

This is an awesome chance for you to put your coding skills to use, build something great and meet other area programmers. Again, attendance is limited to the first 100 people registered so sign up now at http://powerupweekend.eventbrite.com.

Hackathon Flyer

Calculated Fields in CiviCRM

One of CiviCRM’s strengths is the ability to add custom fields to hold specific information about your contacts. One thing it doesn’t offer (yet) is a calculated field type that will present the results of calculations of other fields.  While calculated fields are generally discouraged in relational database design, they are sometimes necessary within a user interface. One suggested method is to add custom code hooks within CiviCRM’s PHP code but as a database guy, I decided on a back-end solution.

Continue reading

MySQL User Defined Function Example: Data Cleanup

(Updated June 9, 2016)

The Challenge

One of my current projects involves migrating a large amount of data away from an old custom Borland Paradox application into a new CiviCRM system. As with too many quickly-constructed apps, this old Paradox database wasn’t especially well designed and, among other the other challenges in salvaging the data, there were no restrictions on how dates could be entered. This means that, in multiple fields within each of the 20,000+ database records, I might see any of the following:

03-14-96
5/20/1975
10/02/83
09051975
07.19.1995
19830211121500

While CiviCRM does have a utility for importing data from CSV and other SQL tables, it was having quite a time with this collection and many of the dates were being mishandled. That’s if the records weren’t rejected entirely for other reasons. Data migration doesn’t often happen with just a few settings adjustments and a click of the Import button.

Continue reading

Coding Basics – Deceptively Simple Programming

In my last post on coding basics, I talked about turning an algorithm into code and used Euclid’s Algorithm as an example of programming a sequence of steps. There’s an even simpler type of algorithm that I want to look at this time. A formula, such as the one for converting Fahrenheit to Celsius, is also a series of steps that must be performed in order to achieve the needed result. These calculations can be represented within C# or other programming languages to include the formula as part of a larger program.

If you’re doing a one-time conversion from Fahrenheit to Celsius, you’re probably going to pull out your pocket calculator or find a good conversion website and enter the necessary numbers. You can do that because either of those resources has the necessary interface to get the necessary input from you. If you’re including this calculation in a program, you need to design your own interface, process that user input from it and return the result to the user in some way. In the case of the pocket calculator or website, other programmers pondered these issues at some point and now it’s your turn.

Continue reading