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问题描述
我想在表的列中插入null.
哪个代表空值? undef或空字符串''.
Which one represents null? undef or empty string ''.
应该使用哪个?为什么?我知道defined并且可以检查.
Which one should be used and Why? I know about defined and that I can check it.
但是我从数据库的角度看更多.
But I am looking more from perspective of database.
哪个人更恰当地表示null?
更新:我正在使用DBI模块.
推荐答案
DBI使用undef表示SQL NULL.空字符串代表空字符串.
DBI uses undef to represent a SQL NULL. The empty string represents an empty string.
但是，某些数据库不能区分NULL和空字符串. Oracle在这里是一个特别的冒犯者. DBI对此无能为力.
However, some databases don't make a distinction between NULL and the empty string. Oracle is a particular offender here. DBI can't do anything about that.
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