Migrating old Delphi 7 code to Delphi XE - unicode really needed?

Question

I have an old application running BDE under Delphi 7, and have now bought Delphi XE. I see a lot of people say the main problem migrating the code is changing to unicode. And possibly a database supporting unicode.

But, do I really have to do this? Can I not just stick to BDE and some "good old string format"?

I am hoping to get away with a quick swap to Delphi Xe here, not necesarily using all new features etc etc....

Rgds PM

Answer 1

We also have many applications running BDE with Delphi-7 and are considering the jump to DelphiXE. The jump is not nice...if you want your program to run in Windows7 64 bit, you will need to convert the BDE or download BDE express or another tool. BDE has memory leak issues so we have converted those components, but will remain in Delphi-7 for older products and use Delphi XE for new projects. Good Luck.

Answer 2

I made the same move from D7 to XE and the change was a killer. My app, like yours includes a database - in my case its Interbase and the Interbase Express components that are part of Delphi. I made the choice to move to Unicode, but it wasn't pretty.

I read the papers, but compared to my experience they seemed incomplete or maybe even incorrect on some points. I think the papers are written from the point of view of a Delphi application with no database. I believe there were critical errors in Interbase Express (Delphi) and in Interbase. I think at least one bug has been fixed in IB and a couple in Delphi - if you move to the XE version. (I don't want to consider going through that again right now).

I wound up adding fixer-uppers in my code to help Delphi out. On the newsgroups and in QC people told me I didn't understand. Well finally, there are changes coming that fix those problems so there must really be issues there someplace.

The conflicting views expressed in this thread indicate the confusion with Unicode. On some of those issues I don't know how it would work, even having gone through it. But, I have doubts about getting through it at all and holding onto the BDE. That could well have built-in issues that will not be fixed, and which you can't deal with. There are some entries in QC you can check to see some of the outstanding issues.

When my application was in D7 my IB database was ansi. When first converted to Delpi XE, it seemed to run ok - although that was only a brief check. IB supports Unicode and I converted my data there. Would you / could you do that with your data? Only after that did I find the problems. I think any meaningful conversion to Unicode means you first convert your data storage to Unicode, then your Delphi app.

So after all that, why are you moving to XE if you don't want unicode? Is it just to upgrade or is there something you are trying to accomplish? I hope this long post helps.

Answer 3

The data fields that connect your data to the database didn't change. A TStringField still has a Value property of type AnsiString, which matches the old behaviour.

When you inspect all the warnings the compiler will spit out, you might come away with little effort and keep the BDE alive.

Besides that I suggest replacing the BDE with a more recent solution in the foreseeable future - not only because of Unicode.

Answer 4

It's pretty hard to avoid using the new UnicodeString which is what string is now aliased to. You can write all your code with AnsiString if you wish, but why bother? As soon as you use any non-trivial library (e.g. RTL, VCL, third-party) you are swimming against the tide. If you do attempt to continue with AnsiString you'll actually make life more difficult for yourself in my view.

If you give it a go you should find that it's not that big a job to move to the new Unicode string type. The vast majority of existing code will work unchanged.