正如我在oracle doc中找到的那样，
SET ESCAPE:
Defines an escape character you can use before the substitution character. The escape character instructs SQL*Plus to treat the substitution character as an ordinary character rather than as a request for variable substitution. The default escape character is a backslash (\).
SET DEFINE:
Defines the substitution character (by default the ampersand "&") and turns substitution on and off.
在我查询之前，我应该这样做吗？：
SET DEFINE off
select 'A&B' from dual;
SET DEFINE on
在我的情况下，使用set escape是必要的吗？