Otherwise, you'll simply get an error. When all the requirements are met, make sure that the user name does not already exist in the database.

否则，只能是一个错误，当所有需求都满足之后，确保用户名不和数据库中现有的用户名重复，如果是重复了，也是返回一个错误。

youdao

Unless otherwise approved by the CIRC, the branches of the insurance companies shall not exist in any other form.

除经中国保监会批准外，保险公司的分支机构不得为其他形式。

youdao

I find consolation with Josef Beuys, who once said that art did not exist to be understood, otherwise it would be redundant.

在约瑟夫·波伊斯那里我得到了安慰，他曾说艺术的存在并不是为了要被理解，否则艺术就是多余的了。

youdao

The system is inefficient, but it supports a class of professional writers, which might not otherwise exist.

NEWYORKER: Publish or Perish

It is not, in fact, regulation of commerce at all, but the creation of commerce through compulsion where voluntary transactions would not otherwise exist.

FORBES: Can ObamaCare Survive an Unconstitutional Mandate?

They could also provide an atmospheric electrical potential difference, which otherwise might not exist, to achieve precisely aimed and timed lightning strikes.

FORBES: "Cloud Computing" of the Not-So-Virtual Sort