Re: [gnome-db] gda_connection_execute_select_command and one column

[Diego Zuccato <diego otello alma unibo it>]

Piotr Pokora ha scritto:

> > Try "SELECT * FROM a_table_in_your_db WHERE false".
> > It returns a model w/o rows. But column descriptions are there.
> And GdaDataModel has 1 column because of this description?
It should have a column for each column in the table (if you use * ).
If you select just a column, it must have exactly one column.

> Yeah, I understand that backened may return additional headers, but
> should I expect that GdaDataModel may also hold headers or any
> additional data, which is not retrieved data?
> GdaDataModel seems to be designed to return X.Y data model.
They are not "additional". It's just the DB saying "prepare to receive 
these columns: cola, colb, colc of types: typea, typeb, typec" before 
actually sending the row data (that might be empty). So you'll have 
three columns in your model, labeled "cola", "colb" and "colc".

> If there's no row and at least one column, then
> gda_data_model_get_value_at seems to be a "bit of luck" function.
Why? You simply shouldn't be using it on a row that doesn't exists...

BYtE,
 Diego.