FRM-40501 unable to reserve record to update

Question

I made a table called groups that has these columns

client_id, 
course_name, 
group_number, day

the primary key is (client_id, course_name) so each group number may has many clients and i want to make a query in my form that displays only the distinct value of group_number and when i update the "day" field it should update day column in all rows with the same group number(for all clients) so I used from clause query and wrote in it: SELECT DISTINCT(GROUP_NUMBER), COURSE_NAME, DAY FROM GROUPS

when i update this form in run time it gives me this error "unable to reserve record to update" what should I do?

Answer 1

This issue occurs during the operation where multi-sessions are updating the same row of the same db table.

Let's have a data block named blk_t1 (table t1 as "query data source name"). Not only setting "locking mode" of blk_t1 from "automatic" to "delayed", but also set forms' "isolation mode" to "serializable".

It worked for me for multi-sessioned workaround.