Which is true about invalid PL/SQL objects?
A)They are automatically recompiled against the new definition of a referenced object when they are called.
B)They must be manually recompiled before they can be used if a DDL is performed on a table that is referenced in the PL/SQL object.
C)They are automatically recompiled against the new definition of a referenced object at the same time as the referenced object is modified.
D)They can be manually recompiled only by using SQL commands.
Answer: A
赵：
A 译：它们在被调用时根据引用对象的新定义自动重新编译。
B 译：如果在 PL/SQL 对象中引用的表上执行 DDL，则必须手动重新编译它们才能使用它们。