How to delete a field in TDbf
lazarus / 16-Databases

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ario · 2010-02-06 11:35

Hi.
I recently started using TDbf as my datasource. I know how to delete a
record from it. But I don't know How to remove a field from a TDbf
table.
I tried:
Code: [Select]Dbf1.FieldDefs.Delete(1);
Dbf1.FieldDefs.Delete(2);
Dbf1.FieldDefs.Delete(3);
Dbf1.FieldDefs.Delete(4);
Dbf1.OpenTable;But nothing happened. Searched all over the internet
but everyone talks about deleting a table or a record, But not about
deleting a field that previously created.
Please help me.
Thanks for your attention guys:)

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cdbc · 2010-02-06 17:17

Hi Ario

I don't think there's an easy way to do this.

IMO you would have to create a new dataset from the edited fielddefs,
and then copy all relevant data to the new one, and finally delete the
old dataset (table)...

hth

Regards Benny

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sasa · 2010-02-06 19:13

Deleting fields (including data) is not possible, since record length
is fixed according to field definition (dBase is textual based table).
As Benny suggest, thus is only possible to create a new table with
news definition and copy relevant data to it.

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Handoko · 2010-02-22 16:51

Hi Ario,
Here is my code perform the job. Of course you need to do some
adaptation.

var
  Dbf: TDbf;
  FieldDefs: TDbfFieldDefs;
begin
  Dbf := TDbf.Create(nil);
  Dbf.TableName := 'C:\Test.dbf';
  Dbf.Open;
  FieldDefs := TDbfFieldDefs.Create(nil);
  FieldDefs.Assign(Dbf.DbfFieldDefs);
  Dbf.Close;
  FieldDefs.Delete(3); // The index of the record you want to delete
  Dbf.RestructureTable(FieldDefs, True);
  Dbf.Free;
  FieldDefs.Free;
end;