How to catch a unique constraint error in a PL/SQL block?

Question

Say I have an Oracle PL/SQL block that inserts a record into a table and need to recover from a unique constraint error, like this:

begin
    insert into some_table ('some', 'values');
exception
    when ...
        update some_table set value = 'values' where key = 'some';
end;

Is it possible to replace the ellipsis for something in order to catch an unique constraint error?

Answer 1

I suspect the condition you are looking for is DUP_VAL_ON_INDEX

EXCEPTION
    WHEN DUP_VAL_ON_INDEX THEN
        DBMS_OUTPUT.PUT_LINE('OH DEAR. I THINK IT IS TIME TO PANIC!')

Answer 2

EXCEPTION
      WHEN DUP_VAL_ON_INDEX
      THEN
         UPDATE

Answer 3

I'm sure you have your reasons, but just in case... you should also consider using a "merge" query instead:

begin
    merge into some_table st
    using (select 'some' name, 'values' value from dual) v
    on (st.name=v.name)
    when matched then update set st.value=v.value
    when not matched then insert (name, value) values (v.name, v.value);
end;

(modified the above to be in the begin/end block; obviously you can run it independantly of the procedure too).