z36_effective_due_date is always zero

Last updated
Save as PDF
Share
1. Share
2. Tweet
3. Share

Article Type: General
Product: Aleph
Product Version: 18.01

Description:
Does anyone know exactly what is going on with z36_effective_due_date?

This appears in our z36 table, and is even transmitted in the raw XML for notices, but it always empty - and the 'Collected Oracle Tables' says that it is for 'future use' - which suggests that the 'effective due date' that we see in the GUI is not based on this at all but is generated in some other way (on the fly?).

Resolution:
The Z36-EFFECTIVE-DUE-DATE relates to the tab100 RECALL-METHOD.

Prior to the addition of tab100 RECALL-METHOD (in version 16), the z36_original_due_date could be changed by a renewal. In order to preserve the original due date, tab100 RECALL-METHOD was introduced. This enabled RECALL-METHODs "2" and "3" described below:

!# RECALL-METHOD
!# Values:1 2 3 Default: 1
!# Type: Text; Max Length: 01
!# tab100 of library: Yes; tab100_<server_type>: No.
!
! "1": Let renewals update the z36_due_date and let recalls update it,
! if the recall-due-date is earlier. Use the z36_original_due_date
! as the "due-date-before-recall". (Let renewals update it.)
! "2": Let renewals update the z36_due_date. Do not actually update the
! z36_due_date to the recall-due-date. But, if the latter is earlier
! than the z36_due_date, use the latter as the "effective due date".
! Leave the z36_original_due_date as the actual, original due date.
! (Do not let renewals update it).
! "3": Same as "2", except always use the recall-due-date as the effective
! due-date --even if it's later

I believe that the Z36-EFFECTIVE-DUE-DATE was introduced with the idea that, when method 2 or 3 is being used, the effective due date would be stored in this field.

But the programs have never been changed to write to or read from this field. Instead, when a program needs the effective due date, it calls the "get_effective_due_date" routine which calculates it as described above.

For a complete discussion of the RECALL-METHOD see the "Due-date Changes" document attached to KB 8192-7815.

Article last edited: 10/8/2013