弹出如下信息.
Saving changes is not permitted. The changes you have made require the following tables to be dropped and re-created.You have either made changes to a table that can't re-created or enabled the option Prevent saving changes that require the table to be re-created
解决方法:
Tools->Options->Designers->Table options->Prevent saving changes that require the table re-creation
把这一项uncheck