Mark Williams

Ran some tests on an in memory dataset of 25K records. Without filter 31ms to iterate the whole dataset (whilst also querying each record to see if it matched the required "document_category_id)." . Filtering first took twice as long to filter and iterate even though the resulting dataset was only 30 records. That sort of answers my question. But would this still hold true with say a million plus records?

I need to work with a potentially large dataset in memory. It has an integer field called "document_category_id". On first loading the table it is sometimes necessary to update records in the table from one document_category_id to another. This might need to be done for several, but not all of the various document_category_ids. Trying to work out what is the most efficient way of iterating. Would it be more efficient to filter on the requored document_category_ids first and then iterate or to iterate on an unfiltered table?

Managed to work out a solution in the end. Sure there will be some issues I haven't considered, but seems to work ok. If anyone is interested here's the code: procedure TForm3.TabControl2DrawTab(Control: TCustomTabControl; TabIndex: Integer; const Rect: TRect; Active: Boolean); var TabName:String; Pt : TPoint; R: TRect; TabUnderMouse:Integer; begin Pt := TabControl2.ScreenToClient(Mouse.CursorPos); TabUnderMouse := TabControl1.IndexOfTabAt(Pt.X, Pt.Y); with (Control as TTabControl).canvas do begin R := Rect; if TabIndex=1 then Font.Style := [fsStrikeout]; if (TabUnderMouse = TabIndex)and Active then Font.Color := TStyleManager.ActiveStyle.GetStyleFontColor(sfTabTextActiveHot) else if Active then Font.Color := TStyleManager.ActiveStyle.GetStyleFontColor(sfTabTextActiveNormal) else if (TabUnderMouse = TabIndex) then Font.Color := TStyleManager.ActiveStyle.GetStyleFontColor(sfTabTextInActiveHot) else Font.Color := TStyleManager.ActiveStyle.GetStyleFontColor(sfTabTextInActiveNormal); tabName := TTabControl(Control).Tabs[TabIndex]; Brush.Style := bsClear; DrawText(Handle, PChar(TabName), Length(TabName), R, DT_SINGLELINE or DT_VCENTER or DT_CENTER) end; end;

I want to show a TabControl with tabs with different font styles. Basically, I want the font in some of the tabs to be shown in strikeout. The app uses a couple of different themes. I thought I'd use the StyleManager to achieve this with the following code: with (Control as TTabControl) do begin tabName := TTabControl(Control).Tabs[TabIndex]; if TabIndex=1 then Canvas.Font.Style:=[fsStrikeout]; Pt := TabControl2.ScreenToClient(Mouse.CursorPos); TabUnderMouse := TabControl1.IndexOfTabAt(Pt.X, Pt.Y); if Active then Details := TStyleManager.ActiveStyle.GetElementDetails(ttTabItemSelected) else if (TabUnderMouse=TabIndex) then Details := TStyleManager.ActiveStyle.GetElementDetails(ttTabItemHot) else Details := TStyleManager.ActiveStyle.GetElementDetails(ttTabItemNormal); TStyleManager.ActiveStyle.DrawElement(Canvas.Handle, Details, Rect); TStyleManager.ActiveStyle.DrawText(Canvas.Handle, Details, TabName, Rect, DT_VCENTER or DT_CENTER, Canvas.Font.Color); end; This sets the colour of the tab background perfectly depending on its state, but has no impact on the font which is always black. However, the font is always black whatever the state of the tab. The color parameter in the DrawText function does not appear to do anything. I've tried setting the canvas font color before calling Drawtext to the stylefontcolor of the tab element in its various states. It has no effect, not does entering any color whatsoever in the color parameter.

Seems to be spam.

I've used it on one smallish app so far. It works perfectly with just one line of code. You may need to tweak a few things if you want to open documents, but it is very straightforward. It took a little bit of time to get my server set up correctly and I needed support from Thinfinity to do this, but the support was superb.

That seems to be the answer. Many thanks. I think I initially went with LoadXMLData because it created the XMLDocument for you in the same step. A false economy it seems!

I have an ISAPI DLL written in Delphi 10.4 running on my server. I exchange information in XML format with the DLL via an app also written in Delphi 10.4. Both the server and the user computer are using Microsoft XML 6.0. I use the following function to convert the exchange xml streams to a string and then to load into IXMLDocument. Function ConvertStreamToString(stream:TMemoryStream):String; Var ss:TStringStream; begin if (Stream <> nil) and (stream.Size>0) then begin Stream.Position:=0; ss:=TStringStream.Create; try ss.CopyFrom(stream, 0); Result:=ss.DataString; finally ss.Free; end; end else Result := ''; end; I load the xml data with: Doc := LoadXMLData(ConvertStreamToString(Response)); This works fine for data received from the server, but not for data submitted to the server. The data is received complete by the server (I save the received stream data to file to test), but something goes wrong with the convertStreamToString function and the LoadXMLData function throws up an error: If I change the stream conversion function to: SetString(Result, PChar(Stream.Memory), Stream.Size div SizeOf(Char)); This works for the DLL on the server, but fails on the local app. It returns a load of junk throwing up an AV on the call to LoadXMLData. I could have a different functions for the server and the local app, but I would rather have some idea as to why this is happening. I guess it is to do with encoding, but can anyone give me a steer as to how I resolve it please?

Yes. As I explained that would work, but I would have to submit a mass of additional data to my server that is unnecessary if you use COALESCE. No. Trying to write it as flexible as poss

You're a genius. I'm an idiot. Why didn't I think of COALESCE. Thanks

Possible, but I'm posting data to a server which then submits the query and it could be an awful lot of unnecessary data to post.

I'd like to use Array DML to update a table, however, I don't want to update all fields every time. In some instances I would like to leave the existing database value untouched for a particular record. In a normal update query I would do something like "UPDATE persons set name=name". I can't see how it's possible to do that for Array DML. SQL.Text :='UPDATE persons SET name=:NAME, email=:EMAIL WHERE id=:ID'; Params[0].DataType:=ftString; Params[1].DataType:=ftString; Params[2].DataType:=ftLargeInt; Params.ArraySize:=2; Params[0].AsStrings[0]:='Delphi'; Params[1].AsStrings[0]:='praxis'; Params[2].AsLargeInts[0]:=794; Params[0].AsStrings[1]:='Mark'; Params[2].AsLargeInts[1]:=795; Execute(Params.ArraySize); The first set of values is intended to overwrite name and email fields. The second set of value is intended to overwrite just the name field and leave the email field as is in the database. I thought (but not with much optimism) that not seeing the parameter for the email field may leave it as is. In fact it sets the value to an empty string. I can't see any method or property of TFDParam that seems to fit the bill. Was hoping there might be an "AsIs" property, but sadly not. I'm sure it can't be the case that I would need to submit multiple array DML's depending on which values I want to change and which ones I want to leave untouched.

Should have mentioned @J. Robroeks in the original post as J posted the solution referred to on SA.

I posted a question on this a while back. Trying to establish whether there was a way of retrieving the ids for new rows inserted using ArrayDML. I had tried using "returning id". That didn't work or rather it didn't work as I had hoped. From memory it inserted just one row and returned the id for that row, By chance I came across this post on stackoverflow: https://stackoverflow.com/questions/66704349/firedac-array-dml-and-returning-clauses I have tried this and get "syntax error at or near {". I can't find anything on "INTO" in this context. Also, using PostgreSQL to test.

I'm trying to use TControlBar for the first time to host controls, mainly TToolBars I have found that when you copy toolbars into the TControlBar it often breaks the toolbar over two rows. This seems to happen where there are 8 or more buttons. I can't find any property either of the controlbar or toolbar to prevent this happening. Most hopeful was TToolbar's Wrappable property, but setting this to false does nothing when the toolbar is placed in a controlbar.