Delphi FDQuery selecting rows without the column name

Question

I have some code on a form which creates a bunch of labels from the column names in the database

I am trying to write another piece of code that uses a FDQuery to select all the records and then create labels based on the value in each row

Currently i have the following.

  while not FDQuery1.Eof do
  begin
    while recordCount < colTotal do
    begin
      newLabel := TLabel.Create(Self);
      newLabel.Parent := panel3;
      newLabel.Align := TAlignLayout.Top;
      newLabel.Text := FDQuery1.FieldByName('Torque2').AsString;
      newLabel.Margins.Top := 10;
      newLabel.Margins.Left := 10;
      newLabel.Margins.Right := 10;
      inc(recordCount);
      FDQuery1.Next;
    end;
  end;

How can i make this create a label with the result of each row dynamically without me needing to actually put the column name like "torque2" as i have here.

So for example on my form the labels will create as follows

row1 
row2 
row3
row4
row5

because right now this code just simply loops one row value

Thanks

FdQuery1.Fields property has a collection for it. Did you try it? — Abdullah Ilgaz
– Abdullah Ilgaz, Commented Jun 10, 2018 at 15:52

Victoria · Accepted Answer · 2018-06-10 18:28:05Z

7

Instead of name based FieldByName method you can access tuple values by the Fields property which is a 0 based indexed collection property.

FireDAC offers more efficient way for accessing data though. Once you have all tuples fetched on the client, you can iterate through the internal data storage this way:

var
  S: string;
  Row, Col: Integer;
begin
  for Row := 0 to FDQuery1.Table.Rows.Count - 1 do
    for Col := 0 to FDQuery1.Table.Columns.Count - 1 do
      S := FDQuery1.Table.Rows[Row].GetData(Col);
end;

That's IMHO easier to read and also saves quite a lot of time because it doesn't move the dataset cursor. Disadvantage might be that you need to have tuples fetched on the client side.

edited Jun 10, 2018 at 18:28

answered Jun 10, 2018 at 14:13

Victoria

7,9522 gold badges23 silver badges45 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Revski Over a year ago

Thanks!! Cant believe i didn't see this before

Victoria Over a year ago

You're welcome! Anyway, try to consider using some layer, like e.g. TGridPanelLayout. It makes your task (building a label based grid) far much easier. And except this iteration FireDAC offers internal storage iteration which is more efficient and easier to read in code. If you were interested, I can add an example to this post.

Revski Over a year ago

Please do i am interested to see

Victoria Over a year ago

I've added example of internal storage iteration. Here is a method that can populate FireDAC dataset object into a TGridPanelLayout control.

Victoria Over a year ago

@MartynA, FireDAC's internal storage is pretty powerful, and efficient. Actually, it seems to be inspired by the C# implementation of the DataTable class (many things does in the same way). Hence questions like this one immediately brings to my mind answers like "Blame something else, not FireDAC" :)

|

Collectives™ on Stack Overflow

Delphi FDQuery selecting rows without the column name

1 Answer 1

6 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related