How to fix the failing "Remove unique constraint to allow duplicate specimen label" change set?

The error "Cannot drop constraint - nonexistent constraint" occurs when either of the following condition is true:

The required unique constraint on catissue_specimen (label) is not present
The constraint is present but the auto-generated name is different from the one expected by the change script

To determine which of the above condition is true, execute below SQL

select
    constraint_name 
from
    user_cons_columns 
where
    table_name = 'CATISSUE_SPECIMEN' and
    column_name = 'LABEL'

If the above SQL returns no rows then condition 1 is true. Otherwise its condition 2.

Solutions

The idea is to add an unique constraint that the change script is anticipating

Add a unique constraint on catissue_specimen (label) using below SQL
SQL 2
alter table catissue_specimen add constraint SYS_C00107672 unique(label);
Restart OpenSpecimen

The idea is to rename the constraint to match with that anticipated by the change script

Rename unique constraint name as below
SQL 3
alter table catissue_specimen rename constraint <output of SQL 1> to SYS_C00107672;
Restart OpenSpecimen