关于SAS数据集加密

数据集通常有三种密码。read ,write,alter. 对应权根分别如下：
read －读
write－写
alter－修改结构


   可alter    不可write
不可alter       可write

能否举例说明上面两种情况，谢谢！

alter and write passwords are not contradictory, they are focusing on different things:

ALTER – restricts who may delete the file, update variable attributes, or create and delete
indexes.

WRITE – restricts who may update the data in the file. For SAS data sets, it restricts who can add,
modify, and delete observations.