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Approach a TTable by its name as a String

Posted on 2001-06-14
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Last Modified: 2010-05-18
Hi All,

I have a set of strings that have the names to different TTables. ('tblCars' or 'tblCycles' as strings).

What i want to do in a simple way, is to approach a table as <name of the table>.FieldByName('Brand').AsString;

Which table is to be used is returned by another query (I pass the table name thrue as a string).

How can you get the correct table if you only have its name as a string?


Greetings,

Bas
0
Comment
Question by:bassch
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6 Comments
 
LVL 17

Expert Comment

by:geobul
ID: 6191951
Hi,
Place a TTable component on your form and set its DatabaseName property.

procedure TForm1.Button1Click(Sender: TObject);
begin
  with Table1 do begin
    Close;
    TableName := 'clients.dbf';
    Open;
    Label1.Caption := FiledByName('LAST_NAME').AsString;
    Close;
  end;
end;

Regards, Geo
0
 
LVL 17

Expert Comment

by:geobul
ID: 6191992
or even better:

function TForm1.ReadAField(TName, FName: string): string;
begin
  result := '';
  try
    with Table1 do begin
      Close;
      TableName := TName;
      Open;
      result := FieldByName(FName).AsString;
    end;
  finally
    Table1.Close;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Label1.Caption := ReadAField('clients.dbf', 'LAST_NAME');
end;

Regards, Geo
0
 
LVL 2

Accepted Solution

by:
Drareg earned 1200 total points
ID: 6192054

You can do this too :

  TTable(FindComponent(<name of table>)).FieldByName('Brand').AsString

Ex.:  If TTable(FindComponent('TableName')).Active Then...

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LVL 17

Expert Comment

by:geobul
ID: 6192063
Hi again,

For already opened TTable use this:

function TForm1.ReadAField(TName, FName: string): string;
var
  i: integer;
begin
  result := '';
  for i := 0 to Form1.ComponentCount - 1 do
    if Form1.Components[i] is TTable then
      with TTable(Form1.Components[i]) do
        if TableName = TName then
          result := FieldByName(FName).AsString;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Label1.Caption := ReadAField('CLIENTS.DBF', 'LAST_NAME');
end;

Regards, Geo
0
 

Author Comment

by:bassch
ID: 6192549
Geo,

By using your method I can no longer use my tables that are already there in my datamodule.

If I had one template TTable than this would be a good option..


Drareg,

This was the line I was looking for.. thanks. I new the FindComponent method, but its funny how fast you overlook some stuff:)




0
 
LVL 17

Expert Comment

by:geobul
ID: 6194262
Hi Bas,
I thought that 'tblCars' or 'tblCycles' were the names of the real tables in the db, not of your ttable components. Glad that you found what you were looking for.

Regards, Geo
0

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