firedac FIREDAC Retrieving To Stream

[Bob Perkins 0]

I'm using an MS SQL database to store large files in a table.  The files are too large for binding to a field directly.  It has to go through a command just like the update to get it into the database.  No exception is raised but the function returns false.  I am finding it difficult to find an answer with Google search.  Any help would be apprciated.

      RIMSDBFireDac.StartTransaction;
      try
        with DCaseAttach do
        begin
          FireDacQuery.SQL.Text := 'SELECT :p = ''D:\TEMP\TEMP.MP4'' FROM caseattach WHERE id = :id';
          FireDacQuery.Params[0].DataType := ftStream;
          FireDacQuery.Params[0].FDDataType := dtHBFile;
          FireDacQuery.Params[0].ParamType := ptOutput;
          FireDacQuery.Params[0].StreamMode := smOpenRead;
          FireDacQuery.Params[1].AsInteger := CaseN;
          if FireDacQuery.OpenOrExecute then
            FireDacQuery.Params[0].AsStream.Read(Buffer, AttachSize)
          else
            ErrorMsg('OpenOrExecute failed.');
        end;
        RIMSDBFireDac.Commit;
      except
        on E: Exception do
          begin
            ErrorMsg('<PullImageFromDB on pulling photo> ' + E.Message);
            RIMSDBFireDac.Rollback;
          end;
      end;
 

[Dmitry Arefiev 106]

https://docwiki.embarcadero.com/RADStudio/Alexandria/en/Support_for_Blob_Streaming_in_FireDAC#SQL_Server_FILESTREAM

https://learn.microsoft.com/en-us/sql/relational-databases/system-functions/pathname-transact-sql?view=sql-server-ver16#return-value