Oracle error handling strategy I am developing a project using oracle. I am writing functions and stored procedures to handle CRUD statements.

My question is in addition to oracle check constraints do I have to check error situations myself or let oracle do the job?

For example if I have a column in a table which is unique and I want to insert into this table I have to check the value to be unique or let the oracle unique constraint do the job and produce an error if it is a repeated value?
In my experience it's slightly faster to let oracle check it and throw an excpetion if the constraint is violated. If you want to do something special when that happens, you can catch the exception and handle it.

For instance:

EXCEPTION
      WHEN DUP_VAL_ON_INDEX
      THEN
         UPDATE ...