尝试了多种组合(并更好地了解了SQL Azure上的用户，登录名和角色之后)，我发现了问题所在:

After trying many combinations (and learning better about users, logins, and roles on SQL Azure) I've figured out the issue:

我试图使用只是数据库用户的 readerUser 登录，而我应该使用登录实例登录，因此是 reader (后跟我已链接的问题的答案).我曾尝试使用 reader 登录，但效果很好:登录后， SELECT 可以输入我想要的任何内容，但无法写/更改/删除任何内容.

I was trying to login with readerUser, which is just a database user, and I should instead have logged in with the login instance, hence reader (as followed by the answer at the question that I've linked). I've tried logging in with reader and it worked perfectly: logging in, SELECTing anything I want, but not able to write/alter/delete anything.