使用WHERE CURRENT OF子句更新

Posted 2021-02-27

I can never remember the syntax on the "FOR UPDATE OF" clause!

DECLARE
    /* Search query using cursor, then update selected columns in the searched table(s)
    */
 
    update_count PLS_INTEGER := 0;
 
    CURSOR people_cur IS
        SELECT zip_code 
          FROM addresses 
         WHERE zip_code = '00000' 
    FOR UPDATE OF zip_code;
BEGIN
    FOR search_rec IN people_cur
    LOOP
        UPDATE addresses 
           SET zip_code = '' 
        WHERE CURRENT OF people_cur;
 
        update_count := update_count + 1;
    END LOOP;
 
    COMMIT;
    DBMS_OUTPUT.PUT_LINE('Updated ' || update_count || ' addresses.');
 
EXCEPTION
    WHEN OTHERS THEN
        DBMS_OUTPUT.PUT_LINE('EXCEPTION - ' || SQLCODE || ': ' || SQLERRM);
        DBMS_OUTPUT.PUT_LINE('Error stack at top level:');
        DBMS_OUTPUT.PUT_LINE(DBMS_UTILITY.format_error_backtrace);
END;