V4RB and changing lengths of varchar fields programmatically

[Erik Mueller-Harder]

> Can someone please give me the exact code for changing the length
> of a varchar field programmatically from Realbasic. Currently the
> length of my Key_Activities field in my Units Base Object is set
> at 3096 but I would like to double that. I have tried various
> ways but none of them seem to get past the debugger.

Hi, Cindy --

Probably the very easiest thing to do would be to change it in the Valentina application itself -- then the database is set the way you want it.

Then change it in Rb:  just change 3096 to 6192.

OK, now that I've read your question more thoroughly, I see you want a programmatic answer.  I can't give you exact code at this moment, but basically I think you'd want to:

1.  Open the database generically (i.e., without all the base object
    properties, etc., defined), with something like

    Dim f as FolderItem
    Dim vdb as VDatabase  // NOT as your subclass!
    
    f = (get folderItem of your db here)
    if not vdb.Open(f) then // error handle
    end if
    
2.  Then find your field and make your change

    Dim vc as VVarChar
    
    vc = VVarChar(vdb.baseObject("baseobjectname").field("varcharName")
    vc.maxlength = 6192

3.  Finally, close the database and re-open it your usual way, making
    sure to have changed your field's maxlength property to 6192 in your
    existing code.


*HOWEVER*, 6192 is not an efficient VarChar size; I believe you'd want to use 6136 or 6648, though my math may be off.  See the Valentina Kernel doc, page 22.

Good luck,

Erik