如何捕获pl/sql块中的唯一约束错误?

EXCEPTION
      WHEN DUP_VAL_ON_INDEX
      THEN
         UPDATE

我相信你有你的理由,但以防万一…您还应考虑改用“合并”查询:

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;

(将上面的内容修改为begin/end块;显然,您也可以独立地运行它)。

我怀疑你要找的条件是 DUP_VAL_ON_INDEX

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