Database diagram support objects cannot be installed because this database does not have a valid owner. To continue, first use the Files page of the Database Properties dialog box or the ALTER AUTHORIZATION statement to set the database owner to a valid login, then add the database diagram support objects
出现上述问题的原因：是因为你把另外一个服务器上的数据库导出后，对于当前数据库没有兼容好，解决如下：
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1。右键点击你的数据库，选择属性
2。转到“选项”
3。在右边标有“兼容级别”的下拉选择“SQL Server 2005中（90）”
4。转到“文件”
5。所有者“文本框中输入”SA“。
6。点击OK
还要执行下列语句：\
EXEC sp_dbcmptlevel 'yourDB', '90';
go
ALTER AUTHORIZATION ON DATABASE::yourDB TO "yourLogin"
go
use [yourDB]
go
EXECUTE AS USER = N'dbo' REVERT
go
eg:
EXEC sp_dbcmptlevel 'aa','90';
go
ALTER AUTHORIZATION ON DATABASE::aaTO "sa"
GO
use aa
go
EXECUTE AS USER = N'dbo' REVERT
go
然后就OK了
来源参考：geekswithblogs.net/shahed/arch…
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