Delphi XE2 - handling blob fields

Question

We are trying to make our app unicode compatible and we are migrating from delphi 2007 to delphi xe2, we came across few issues and need suggestions regarding them

1) one change is to store blob data having unicode strings in database

We store huge xml data as blob in database, but in latest delphi version(xe2), blob is treated as an array of bytes. So what should be done to store blob data in database, have tried like converting Param.AsBlob := WideBytesOf(xml) but that doesn't seem to work.

2) Also we use HyperString from EFD systems for faster string manipulations, but now the unicode version of this library is not available, have compiled the code by changing the ansistring to string and tried to modify few assembly language instructions but was succesful with only few till now, so can any one suggest any alternative for faster string manipulations

HyperString was much more relevant in the days of Delphi 1.0. Later versions of Delphi produced more optimized code. I'd suggest replacing this code wherever possible with equivalent pascal code. It would be a huge undertaking to rewrite all of the HyperStr ASM code to work with Unicode strings and I don't know that the effort would be worth the trouble. — Mike W
Thanks for the input, we will look into replacing the calls of HyperStr with Delphi library functions — ravi12

AirWolf AirWolf · Accepted Answer · 2013-08-04T19:40:30

I was searching the internet about half a year how to properly put a Blob in a Database and i found one sollution that worked for me perfectly maybe it will help you also:

Image - TcxImage component MainQuery - TQuery component MainQueryPicture - its a Blob field in from the database stored in the Query component through the Field Editor ImagePath - String variable which hold the path to the image file

    MainQuery.Edit;
    if Image.Picture.Graphic <> nil then //if there is an image loaded to the component
    begin
      MainQueryPicture.LoadFromFile(ImagePath); //load the image to a blob field
    end;
    MainQuery.Post; //post any changes to the table

Hope it helps.

Delphi XE2 - handling blob fields

1 Answers