i建议您采用方法 1 ，但不要直接抛出异常.请在对其进行检查之前，先检查它是否与唯一键相关，并显示一条正确的消息，指出名称已存在于数据库."

i will suggest you to go with approach 1 but do not throw the exception as it is.Check it before like if it''s related to unique key display a proper message saying "Name already exists in the database."

在添加之前检查所有项目将是一项开销.我建议你选择第一名.只需确保正确处理异常，以使用户在看到技术错误时不会惊慌失措. :)

Checking all the items before adding will be an overhead. I suggest you go with #1. Just make sure to handle exceptions properly so users will not freak out when they see technical errors. :)