Archive for October 2009
I have a few reasons to thank Julie Lerman. First her excellent book on Entity Framework (Programming Entity Framework) saved me all sorts of pain and suffering when I recently did a project using EF for data access. EF is a great tool and will be even better in the future but the first release can be a bit unintuitive at times and especially a pain in the butt when dealing with certain kinds of stored procedures. Her book saved me from wasting time, wasting resources and the frustration of going down blind alleys.
Today she saved me again. I tried to change the namespace of the data access layer of my project and after a couple of minutes of find and replace I could see I was wandering into a minefield. So I learned first hand that you have to come up with a good namespace right at the beginning because changing it after you’ve got an established EF model makes a trip to the dentist look like fun.
So I right-clicked the folder and selected “Revert”. And of course that solved everything … not! Next time I tried to run the app I got this helpful message: “Schema specified is not valid. Errors: Models.XXXX.csdl(3,4) : error 0019: The EntityContainer name must be unique. An EntityContainer with the name ‘XXXX’ is already defined.”
I tried to debug it myself for a while, but no luck so I turned to Bing and found that other people posting to various forums had hit a similar problem with no real solutions provide. Then I found a page on Julie’s site (Entity Framework Error 0019) that solved the whole thing.
So, thanks Julie, and keep writing the great books!
The index is useful if you are wondering which languages are popular and which are most used, etc., but more interesting is to view the trends of usage by clicking on the language names in the ratings table.
For example, as of right now (Oct 2009) Java is the top language, so if you were a new programmer you might be tempted to learn Java because it’s the most popular and there is probably lots of demand for Java programmers. But before you rush over to Amazon and buy Head First Java or Learning Java, click on the link to the long term popularity trend of Java and you might have second thoughts: Java’s popularity is on the wane. It’s popularity graph from 2001 to now, goes down at a 30 degree angle.
From its peak in 2001 in the #1 position with a rating of 26.5%, Java crashed to second place and a rating of 14.8% in 2004. It recovered a bit by the end of 2005, but has continued to fall ever since. If the trend continues then it won’t be #1 much longer.
In contrast, the long term popularity trend of C# is quite the opposite. It’s graph is going up at almost a 45 degree angle. So the neophyte programmer may be tempted to buy Learning C# 3.0 or C# in Depth: What you need to master C# 2 and 3.
It all makes fascinating reading, so head on over and take a look.