[fpc-pascal]SQLite and NULL Strings...

[James Mills]

On Mon, Jul 14, 2003 at 09:59:17AM +0200, Michael Van Canneyt wrote:
> 
> 
> On Mon, 14 Jul 2003, James Mills wrote:
> 
> > Hi,
> >
> > This is a very weird behaviour I've found of either SQLite, or the Unit.
> > I'm not sure... I have been discussing this same problem on the SQLite
> > mailing list but without success there, so perhaps someone here might
> > know...
> >
> > I have attached a test database, which contains 1 database entry, null
> > strings are inserted using NULL... Check the database schema yourself.
> >
> > The problem therein lies in the fact that test3.pas returns "" for the
> > query: SELECT channelNotice FROM channels WHERE channel LIKE '#ProLogiTech';
> > It should return a null string as it does in test2.pas and in the sqlite
> > shell program.
> 
> The problem is that an implicity conversion from Nil to empty string is
> done. You cannot solve this as long as stringlists are used to contain
> the data. (ok, you could set 'Null' as the string, but that is sloppy)

"is done." in what ? The SQLite library or TStringList ?

> 
> You'd need to have (as a minimum) an array of TField records:
>   TField = Record
>     IsNull : Boolean;
>     Value : String;
>   end;
> 
> But this will require major changes, so I suggest trying to find or
> implement a TDataset descendent for SQLIte, this will solve most of
> your problems at once.

How major would the changes be ? Otherwise I'll try and search for a
TDataset descendent ? Couldn't I write a descendent myself ? (I've kinda
of done something similar in creating a TDatabase descendant..., but it
doesn't solve my problem)

cheers
James

> 
> Michael.
> 
> 
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-- 
-
- James Mills
Zero Defect Software Engineers Group - ZDSEG