Re: 4 - subfiles

["John Taylor" <john.taylor@xxxxxxxxxxxxxxx>]

Booth,

 

If you're really concerned about the read performance, you could simply define three additional subfiles. Load the first (default) when the pgm starts, then switch the subfile you're displaying based on the user's selection. If the user selects a view that hasn't been initialized yet, go out and do the read at that time, otherwise just keep alternating the sfile that is displayed.

 

Another alternative, and one that I have used a few times in the past, is to only use a single input file regardless of the number of logical views that the user can choose from. The initial subfile load is performed using the default sort order. When the user requests a sort on a specific column, I just perform a standard shell sort right in the program.

 

For what it's worth, I don't think that you are dealing with enough records for it to really be much of an issue which method you choose.

 

Regards,

 

John Taylor

 

 

----- Original Message -----

From: boothm@earth.goddard.edu

To: midrange-l@midrange.com

Sent: Wednesday, November 03, 1999 19:08

Subject: 4 - subfiles

Here's a subfile question.  I'm not very good with them.  I have a display screen showing a subfile with 4 fields.  Each field is the key to a logical file so there are 4 logical files in the F-specs.  For clarity, lets call the fields LastName, FirstName, ExtNbr, DeptName.  I want the user to be able to display any one of the 4 logical files.  I know the file will never grow beyond 999 because the ExtNbr field is 3/0, and because there's only about 150 extensions now, anyway.   Every time the user selects another logical to display I clear the subfile and  reload the entire file to the subfile.  With a dozen test records I'm getting sub-second reloads.  Now, as the number of records increases it seems to me that reload times will increase.  Still, I know that 5000 records load in 11 or 12 seconds so the time for about 200 records will probably be a second or two.

However, it occurs to me that having loaded the subfile, I shouldn't need to read the data file again.  I am thinking there must be an easy way to save the subfile in case it is needed again, instead of just clearing it, or am I tilting at windmills?