Load all records at once into a Stringlist

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{ Loading millions of records into a stringlist can be very slow }

procedure TForm1.SlowLoadingIntoStringList(StringList: TStringList);
begin
  StringList.Clear;
  with SourceTable do
  begin
    Open;
    DisableControls;
    try
      while not EOF do
      begin
        StringList.Add(FieldByName('OriginalData').AsString);
        Next;
      end;
    finally
      EnableControls;
      Close;
    end;
  end;
end;

{ This is much, much faster }
procedure TForm1.QuickLoadingIntoStringList(StringList: TStringList);
begin
  with CacheTable do
  begin
    Open;
    try
      StringList.Text := FieldByName('Data').AsString;
    finally
      Close;
    end;
  end;
end;

{ How can this be done?

  In Microsoft SQL Server 7, you can write a stored procedure that updates every night
  a cache table that holds all the data you want in a single column and row.
  In this example, you get the data from a SourceTable and put it all in a Cachetable.
  The CacheTable has one blob column and must have only one row.
  Here it is the SQL code: }


Create Table CacheTable
(Data Text NULL)
GO

Create

procedure PopulateCacheTable as
  begin
  set NOCOUNT on
  DECLARE @ptrval binary(16), @Value varchar(600) -
  - a good Value for the expected maximum Length
  - - You must set 'select into/bulkcopy' option to True in order to run this sp
  DECLARE @dbname nvarchar(128)
  set @dbname = db_name()
EXEC sp_dboption @dbname, 'select into/bulkcopy', 'true'
- - Declare a cursor
DECLARE scr CURSOR for
SELECT  OriginalData + char(13) + char(10) - - each line in a TStringList is
separated by a #13#10
FROM    SourceTable
- - The CacheTable Table must have only one record
if EXISTS (SELECT * FROM CacheTable)
Update CacheTable set Data = ''
else
Insert CacheTable VALUES('')
- - Get a Pointer to the field we want to Update
SELECT @ptrval = TEXTPTR(Data) FROM CacheTable

Open scr
FETCH Next FROM scr INTO @Value
while @ @FETCH_STATUS = 0
begin - - This UPDATETEXT appends each Value to the
end
of the blob field
UPDATETEXT CacheTable.Data @ptrval NULL 0 @Value
FETCH Next FROM scr INTO @Value
end
Close scr
DEALLOCATE scr
- - Reset this option to False
EXEC sp_dboption @dbname, 'select into/bulkcopy', 'false'
end
GO

{ You may need to increase the BLOB SIZE parameter if you use BDE }