yes。 看来你们的编号是primary key （或part of primarykey） 不许有重复的

The primary key of a relational table uniquely identifies each record in
the table. It can either be a normal attribute that is guaranteed to be
unique (such as Social Security Number in a table with no more than one
record per person) or it can be generated by the DBMS (such as a
globally unique identifier, or GUID, in Microsoft SQL Server). Primary
keys may consist of a single attribute or multiple attributes in
combination.

所有跟帖： 

• 谢谢你的解释，听起来非常专业啊。 -HenryLi- ♂ (0 bytes) () 01/05/2012 postreply 08:28:09

• copied。：） -130131- ♀ (0 bytes) () 01/05/2012 postreply 08:35:26