Subject Re: [IBO] How open a dataset with only a Bookmark record?
Author Marco Menardi
After some investigations, seems that bookmark does not:
"saves the current row's KeyFields[n].Value properties as variants
cast to strings, in a semicolon-separated string, in the SQL column
It saves an hexdecimal conversion of the keyfields, without any
separator in them (so now I understand the method KeyFields.RowData :=
ABookmark; found in the IBO code).
So rebuild fields value from a bookmark and assign them to key fields
(or, as I need, SearchBuffer) seems not to be trivial...
Marco Menardi

--- In, Helen Borrie <helebor@t...> wrote:
> At 11:29 AM 16/03/2003 +0000, you wrote:
> >I have a bookmark for a lookup dataset. I want to use that bookmark
> >for opening another dataset on the same record.
> >I don't want to use something like:
> >with qryCustomer do
> >begin
> > Open;
> > Bookmark := workBookmarkString;
> >end;
> >because this way all the data is requested to the server and THEN the
> >right record is located.
> >I want instead have the behaviour the IBO Search has, i.e. return only
> >the desired record, but I don't know how to make my workBookmarkString
> >being used as a search criteria.
> >In other words, I would like to have something like:
> >with qryCustomer do
> >begin
> > Search;
> > Bookmark := workBookmarkString;
> >..First;
> >end;
> >
> >that does not work.
> >I don't want to fill the other field values for a search, since I need
> >a generic solution and Bookmark produces always an unique key.
> >How can I do?
> KeyFields is a TIB_Row containing a TIB_Column object for each of the
> KeyLinks columns of the row in the row buffer. Bookmark saves the
> row's KeyFields[n].Value properties as variants cast to strings, in a
> semicolon-separated string, in the SQL column order.
> So, if you want to apply the Bookmark values to the parameters of the
> dataset's SQL generically, you could parse the values out an apply
them to
> the Params[n] - but only if your Params were in the same order as
the SQL
> order of the KeyLinks.
> Instead of using Bookmark, you could extract KeyFields.FieldName and
> KeyFields.Value out into a stringlist of the format FieldName=Value.
> This gives you a way to get and store the key field names and values
> generically, and independently of SQL order; then you can construct a
> generic ParamByName assignment procedure by looping through the
> e.g., something along these lines:
> procedure MyForm.GetSelectedRow (Dataset: TIB_Query);
> var
> StoredParms: TStringlist;
> ii: integer;
> begin
> if Dataset.IsEmpty then
> Exit;
> StoredParms := TStringlist.Create;
> try
> with Dataset, StoredParms do
> begin
> for ii := 0 to KeyFields.ColumnCount - 1 do
> Add(KeyFields[ii].FieldName + "=" + KeyFields.AsString);
> Close;
> for ii := 0 to Count - 1 do
> ParamByName(Names[ii]).Value := Values[Names[ii]];
> Open;
> end;
> finally
> StoredParms.Free;
> end;
> end;
> Helen