Otherwise , if the full - text unique key size exceeds the maximum size allowed 900 bytes , full - text population will not be able to proceed 否则，如果全文唯一键的大小超过所允许的最大值（ 900个字节） ，全文填充将无法继续进行。
Names vs . keys : looking at the relational database , it might not be apparent that employeeid is a meaningless , unique , system - generated key 名称与键：查看关系数据库时，可能无法理解employeeid是一个系统生成的无意义的唯一键。
In visual basic , but the value can be a null reference nothing in visual basic and does not have to be unique 每对必须有一个唯一键，且这个唯一键不能为空引用（在visual basic中为nothing ） ，但是值可以为空引用（在visual basic中为nothing ）且不必是唯一的。
The statement was aborted because it would have caused a duplicate key value in a unique or primary key constraint or unique index identified by 0 defined on 1 此语句已放弃，因为它会在唯一键约束或主键约束中或在{ 1 }上定义的{ 0 }标识的唯一索引中导致重复键值。
