您需要阅读一本书(任何本书！)，或在网络上参阅许多教程...

唯一键和主键之间有区别.
MSDN:主键约束 [ MSDN:唯一键约束 [

You need to read a book (any book!) or refer number of tutorials on web...

There is a difference between unique key and primary key.
MSDN: Primary key Constraints[^]

MSDN: Unique Key Constraints[^]

After creating a table, you define the columns. There is a property window associated with a column created, use that for setting various properties/constraints for that column. There is a right click option too for setting selected constraints.

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