Queue.LastInQueue ?

lumper5 · **Posted:** November 13th, 2008, 9:37 am

What's the best way to discover the TDataSet for the last item in queue. EG: I want to add a promo to the QueueBottom iff the last item in queue is of songtype = "S" so as not to play a promo after songs only, not after other Ps or Is or Js, etc...

Song := Queue.NextInQueue; works well to discover the first item in queue... but how to discover the last item?

Thanks,
K

Elevatorboy · **Posted:** November 13th, 2008, 9:52 am

Query the queuelist, examine the last item in the data set.

q.v. TDataSet in the Help files.

lumper5 · **Posted:** November 13th, 2008, 11:50 am

Problem is that queuelist doesn't store songtype.

Moonbase · **Posted:** November 13th, 2008, 12:08 pm

You might want to use something like the code snippet below. Just bear in mind that the function »SongList« only returns the fields ID, songID, sortID, requestID, artist, title, and duration in the TDataSet returned.

Code:

PAL.LockExecution;
var Q, QInfo: TDataSet;

if (not Queue.IsEmpty) then
begin
  // Queue not empty, get last song in Queue
  Q := Queue.SongList;
  Q.Last;

  if (not Q.EOF) then
  begin
    // need to get extra info that is not in »queuelist« table, so read »songlist« table
    QInfo := Query('SELECT * FROM songlist WHERE songID = :id',[Q['songID']], True); // r/o query
    QInfo.First;
    // you should now have all songlist info in »QInfo['…']«
    if (QInfo['songtype'] = 'S') then
    begin
      // add promo to Queue Bottom
    end;
  end;

  Q.Free;
  QInfo.Free;
end;

PAL.UnlockExecution;

Untested, but I guess it should work.

lumper5 · **Posted:** November 13th, 2008, 12:24 pm

Thanks - that was the right idea. A small tweak and it worked great. Seems odd that queuelist wouldn't store a little more info like songtype, but so it goes. Thanks for the helps.

FesterHead · **Posted:** November 13th, 2008, 1:13 pm

This could also be done without the outer check:

Code:

PAL.LockExecution;

var QInfo : TDataSet = Query( 'select sl.songinfo from songlist sl, queuelist ql where sl.id = ql.songid order by ql.id desc limit 1', [], True);
if ( QInfo[ 'songtype' ] = 'S' ) then
begin
  // add promo to Queue Bottom
end;

QInfo.Free;
PAL.UnlockExecution;

SQL validated on MySQL; salt to taste for other dialects

Elevatorboy · **Posted:** November 13th, 2008, 1:18 pm

Thanks, Moonbase. Tweaked it a bit and this does work:

Code:

//PAL.LockExecution;
var Q, QInfo: TDataSet;
var SI : String;

if (not Queue.IsEmpty) then
  begin
     Q := Queue.SongList;
     Q.Last;
  end;
  WriteLn(Q['SongID']);
  WriteLn(Q['title']);
  SI := Q['songID'];
  WriteLn(SI);
  //Get additional info about song
    QInfo := Query('SELECT * FROM songlist WHERE ID = :ID',[Q['songID']], True);
    WriteLn(QInfo['ID']);
    WriteLn(QInfo['title']);
    WriteLn(QInfo['songtype']);
    // You should now have all songlist info in »QInfo['…']«
    //Put a jingle in the queue
    if (QInfo['songtype'] = 'S') then
    begin
      CAT['Jingles (All)'].QueueBottom(smLemmingLogic,NoRules);
    end;


  Q.Free;
  QInfo.Free;
//end;

//PAL.UnlockExecution;

@lumper
Throw out the obvious check lines, tweak accordingly, you should be good to go.

Elevatorboy · **Posted:** November 13th, 2008, 1:23 pm

Or you could do it Steve's way. :lol:

Moonbase · **Posted:** November 13th, 2008, 2:09 pm

Steve, my PAL hero

Always a way to optimize things. Great code.

lumper5 · **Posted:** November 13th, 2008, 2:20 pm

Here's what worked for me... based on Steve's code:

QInfo := Query( 'select songtype from songlist AS sl, queuelist AS ql where sl.id = ql.songid order by ql.id desc limit 1', [], True);

while NOT (QInfo['songtype'] = 'S')

wait
else
add to QueueBottom

FesterHead · **Posted:** November 13th, 2008, 6:49 pm

Both return a TDataSet but one has the option to return the songtype field while the other does not.
As we say in Hawaii: if can, can; if no can, no can.

Forum rules

Queue.LastInQueue ?

Who is online