PL/SQL「Where of Current of」vs「ROWID」

Question

爲什麼Oracle在使用「rowid」時爲什麼使用「where current」語法？示例：

BEGIN 
    FOR rec IN (SELECT t.column1, t.rowid rid FROM test_table) LOOP 
    UPDATE test_table tb SET column1 = some_function(rec.column1) WHERE tb.rowid = rec.rid; 
    END LOOP; 
    COMMIT; 
END; 

DECLARE 
    CURSOR cur IS SELECT t.column1 FROM test_table; 
    param1 test_table.column1%TYPE; 
BEGIN 
    LOOP 
    FETCH cur INTO param1; 
    UPDATE test_table tb SET tb.column1 = some_function(param1) WHERE CURRENT OF cur; 
    EXIT WHEN cur%NOTFOUND; 
    END LOOP; 
    COMMIT; 
END; 

Answer 1

Where Current Of用於標識遊標中的最後獲取行。這是更安全的，因爲你有100％的信心，即f.e.你從curosr更新最後取得的行。使用Rowids會有危險，因爲搞砸事情真的很容易。