ER Diagram in Sql server 2005

To see the ER diagram for sql server 2005.

• Right click the Database Diagrams on the particular table and select new database diagram

Error i Got

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.

How i Solved

• Right on database ,Choose properties
• Go to options menu
• check whether the compatibility level :SQL Server 2005(90)
• Click ok

Still i got the same error . After that i executed
ALTER AUTHORIZATION ON DATABASE::DatabaseName TO sa

Every thing working fine and i got ER diagram