修改数据库时，提示：
saving changes is not permitted.The changes you have made require the following tables to be dropd and re-created.You have either made changes to a table that can’t be re-created or enabled the option Prevent saving changes that require the table to be re-vreated.
解决方法：不要捉急，这是因为你设置了保存修改时重建表（一般是默认的）
1.回到SQL Server Studio(SSMS)首页。
2. 选择Tools–>Options–>Designers–>Table and Database Designers ,去掉Prevent saving changes that require table re-creation .