问题
I've got a SQL Database Table, which has 35 existing records. One of the fields in this table is called Name, nvarchar(100), not null
However, due to a recent change, I need to make this column nullable.
When I change the column to allow nulls in SQL Server Management Studio, and go to save my changes, I get the following error:
Saving changes is not permitted. The changes you have made require the following tables to be dropped and re-created
How can I allow this to automatically be dropped and re-created?
回答1:
I've found the solution. Go to "Tools > Options > Designers > Table and Database Designers":
回答2:
It's a setting in SSMS.
Tools - Option - Designers - Prevent saving changes that require table re-creation
回答3:
I had the same problem; wanting to Allow Nulls for a column that previously did not. Consider MS's warning to NOT turn off this option: http://support.microsoft.com/kb/956176
And their recommendation to use Transact-SQL to solve the problem, e.g. alter table MyTable alter column MyDate7 datetime NULL
This solved it for me.
来源：https://stackoverflow.com/questions/7711026/save-changes-is-not-permitted-when-changing-an-existing-column-to-be-nullable