oracle - How to validate the database after migration -

we have oracle 11g database running on amazon ec2 , trying migrate amazon rds. both source , target oracle db. best way validate tables , data in both source , target after migrating database. how make sure migrated without data loss.

thanks in advance.

create database link old_db old database , compare data

select * tab1 minus select * tab2@old_db union select * tab1@old_db minus select * tab2@old_db  

the result of select must empty

select desired tablenames by

select table_name user_tables 

and build select statement above execute dynamically table table, like

declare   l_found number;   l_sql   varchar2(500); begin   l_rec in (select table_name user_tables) loop     begin       -- assume database link old_db exists       l_sql := 'select 1 dual exists (select * ' ||                l_rec.table_name || ' minus select * ' ||                l_rec.table_name || '@old_db union ' ||                'select * ' || l_rec.table_name ||                '@old_db minus select * ' || l_rec.table_name || ')';        dbms_output.put_line(l_sql);        execute immediate l_sql         l_found;        dbms_output.put_line('difference found :' || l_rec.table_name);     exception        when no_data_found         dbms_output.put_line('okay :' || l_rec.table_name);         -- okay         null;        when others         -- error (check if table exists, ...)         dbms_output.put_line('error :' || l_rec.table_name);      end;   end loop; end;