[fpc-pascal] TSQLQuery UniDirectional and SaveToStream

[LacaK]

Dimitrios Chr. Ioannidis  wrote / napísal(a):
> Hi all,
>
>   i will appreciate a little help / advice / anything for the 
> following problem i'm having.
>
>  I need to use the xmldatapacketreader to transfer datasets between 
> free pascal and delphi.
>
>  The problem i'm having is that i can't use UniDirectional and 
> SaveToStream at the same time ( getting DataBaseError(SUniDirectional) 
> ) and for big datasets the memory goes .....
>
>  So, does anyone have any idea how to use xmldatapacketreader ( which 
> implies SaveToStream ) and UniDirectional ?
>
As you can see there is CheckBiDirectional in the begining of 
SaveToStream ...
I am not sure, why is there such check (may be that bookmarks are used 
and bookmarks are not supported by unidirectional datasets?)
AFAIU saving is performed in sequential order from first record to last 
... and update buffer is evaluated, but unidirectional dataset can not 
have update buffer ... so at first look it seems, that saving can be 
performed also on unidirectional dataset (as it supports First and Next 
methods)
May be that CheckBiDirectional is there only for symmetricity with 
LoadFromStream ... and LoadFromStream can not be performed on 
UniDirectional datasets. (because they are not updateable and do not 
handle cached updates)

What you can do is remove check: CheckBiDirectional in the begining of 
SaveToStream ant try what happens ;-)

-Laco.