> Adam, Alan,
>
> >If TableB contains some other fields, then I can understand the
> >structure. If however there are no other fields aside from the
> >FIELDID in tableB, then I don't know what is achieved by creating the
> >table in the first place.
>
> >Normalisation 101: Duplicated data is often a sign that the database
> >structure needs to be normalised.
>
> In effect is tableA that contains more data (columns).
> TableB contains the same data of TableA but not ALL the data.
> As said and simplifing the structure (that obviously is more complex):
>
> TableA
> FieldID FieldA FieldB FieldC
>
> TableB
> FieldID FieldA(the same of tableA) FieldC(the same of tableA)
> It does not contains FieldB
>
> At this point It would be correct to create (for normalisation
> database) one
> only table and leave blank FieldB when not necessary (for the contability
> movement of tableB that do not need it) ?

absolutely! - that's what it's all about - make a CHAR(2) field if you like
which contains 'CR' or 'DB' for the type of transaction
Alan

>
> Thank you very much for your help
> Adriano