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#1 Created at ... [Delete] [Delete and Lock User]

添加唯一索引：
>ALTER TABLE students
ADD CONSTRAINT uni_name UNIQUE (name);

只添加唯一约束而不添加唯一索引：   
>ALTER TABLE students
ADD UNIQUE INDEX uni_name (name);

#2 Created at ... [Delete] [Delete and Lock User]

顺序反了吧？

添加唯一索引：

> ALTER TABLE students

ADD UNIQUE INDEX uni_name(name);

只添加唯一约束而不添加唯一索引：

> ALTER TABLE students

ADD CONSTRAINT uni_name UNIQUE(name);

#3 Created at ... [Delete] [Delete and Lock User]

确实写反了。