SQL Concurrency versus JDO, and why I want to make the switch

Small update tonight. I managed to not do much tonight except think. And think. And plan. The outcome is a decision to "scrap" what I have so far on the simulation and start new. Including, (most likely) the database.

And here I was promising the material decoder, huh? Not that it took very long to get nearly finished with that. Another couple of days and I'll probably have that finished, I just need to go through some organization first.

So what am I changing in starting new? Let's go into one of my standard bullet lists:

• (Probably) Removing the SQL from my side of the coding by using Java Data Objects.
• Creating classes for the different objects (like planets and ships) rather than tables per se.
• Truly attempting to take advantage of the object-oriented nature of Java, a la Budd.
• Avoiding so-called "Concurrency" issues
• (Probably) Making the code easier on me to develop.

Java Data Objects, or JDO, are a method of storing entire Java Objects within a database. In my case, by creating a class for each in-game item, I can then store the classes in the database. This becomes useful in terms of the concurrency issues mentioned above. Concurrency in SQL is a problem where multiple users attempt to access the same data at the same time. When one person edits the data, the second person may well overwrite those changes even though the information they based it off of is no longer accurate. Generally this is handled by locking the row, so that only one person can access data at a time.

This is a major problem in my program because of the nature of the database I built, and how it would be accessed. The database is built with 'foreign keys,' or references to other tables, so that all of the data is interconnected. If one user is accessing all of the necessary data to run their empire, then a significant portion of the database is locked up while they're doing that work. Not a very user-friendly methodology. On the other hand, if the planets and ships and everything else are stored as independent objects, the user only accesses those that belong specifically to them and there aren't concerns about simultaneous edits.

I'm not too well-versed in the JDO things yet (I've just stumbled upon them today, really), so I'm not certain, but I do get the impression that using JDO means not needing to use SQL, and this simplifies my coding as well as removing the SQL altogether. Unfortunately, while I've found books that cover JDO, I can't find any at a library near me. I'm considering purchasing a copy somewhere off the web, but for now I'm going to try using the online documentation for it. Until I run into major issues, I'll probably stick with that.

My next couple of days are pretty slim in terms of time spent in-school, so hopefully I'll have a nice structure fleshed out and work started by... the weekend, at the latest? Wish me luck on that!