It's definitely worth investing some time in your table design before you get too far. Might be worth creating a new post under the "Theory and Practice of database design folder" and describe your business model in English terms. Also consider posting your d/b with sample data.
Hopefully someone can provide some good links on relational database design. You can of course google but I found that some tend to be better than others at explaining the main principles.
I looked into the relational stuff and it's hardly applying to my database. I guess this is why I didn't think about it before. The reason is that it's an application that is not the main database. Let me explain myself.
We've got a web application that stores the same kind of information on a server. That is the true and real database people go look into for information.
My application/form/database is just a tool. Directly on the web application I mentionned above, it is impossible to manually do massive information update. The only way to do it massively is by sending an excel file to the managers of this application and they will then do a massive import in the web database. Other than that you have to load the pages one by one to access the record and click another time to edit it. Many loadings.
To put it simply, the informations that comes into my database come from this server database, and the information isn't always keeping its integrity as people from around the company manualy enters (sometime) random values.
Now you might say it's kinda pointless to developpe a tool for this, but know that I'm working on making the output of my database workout with the server database. One of the main reason why this tool is useful is because it's much much much much much faster than the web application and we have times of the year when we need to rush the information into the server database.
So I've pretty much explained it.
On the side line, I'm still looking into that Case Sensitive problem, haven't really figure it out yet.