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Asked: 2021-01-04T11:53:24+00:00

APEX 20.2: Creating Karaoke screens

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I am playing around with APEX creating a Karaoke screen as a learning exercise. This requires a dynamic action to read song words from a database and at intervals, automatically display a set of words on the screen.

If I use javascript, I find it can do everything but read a database.

If I use PL/SQL, I find it can do everything except refresh the screen during the song, so the only words I see on the screen are the last words of the song. [Note: I am updating the screen using: apex_util.set_session_state(‘P3_SONG_WORDS’, v_song_line);]

Are there any solutions to these problems?

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2 Answers

  1. You can execute PL/SQL code to read the value from the database using JavaScript. Below is an example:

    Click on the process tab and then click on the Ajax Callback node and create a process. And add the PL/SQL code in it to get the song words, for example:

    Declare
   v_words varchar2(1000);
Begin
   select song_words into v_words
      from song where song_id = :p1_song_id;
 
  htp.p(v_words);

exception 
   when others then 
    htp.p('ERROR');
End;

    Give any name to the above Ajax callback process, for example, AjxGetWords. Now call it using JavaScript below:

    apex.server.process('AjxGetWords',
{
pageItems : '#P1_SONG_ID' // page items to submit
}
,
{
dataType : 'text', success : function(data)
{
if(data != 'ERROR') apex.item('P1_SONG_WORDS').setValue(data);
}
}
)

    Try it.