ORA-01779: cannot modify a column which maps to a non key-preserved table

Oracle issue :
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ORA-01779: cannot modify a column which maps to a non key-preserved table

Reason : 


      update (
      select ur.sysadmin FROM user_role ur
      INNER JOIN user_profile up
      ON up.user_id = ur.user_id
      INNER JOIN role r
      ON r.role_id      = ur.role_id
      WHERE ur.sysadmin = 1
      and ( up.sysadmin = 0
      or r.sysadmin     = 0 )) t
      SET t.sysadmin = 0;
   
   Because inline view returns 0 rows and oracle could figure out records to be updated.
   
Solution :
  
   update user_role usr set usr.sysadmin = 0
      where exists (
      select ur.* FROM user_role ur
      INNER JOIN user_profile up
      ON up.user_id = ur.user_id
      INNER JOIN role r
      ON r.role_id      = ur.role_id
      WHERE ur.sysadmin = 1
      and ( up.sysadmin = 0
      or r.sysadmin     = 0 ));
   
We can also use merge statement to update rows in join

          merge INTO resource_master c USING resource_master p ON (p.resource_id = c.parent_id)
        WHEN matched THEN
          UPDATE SET c.active = 0;