EXEC sp_dbcmptlevel ‘yourDB’, ’90′;
go
ALTER AUTHORIZATION ON DATABASE::yourDB TO “yourLogin”
go

Syntax

sp_dbcmptlevel [ [ @dbname = ] name ]
    [ , [ @new_cmptlevel = ] version ]

Arguments

[ @dbname = ] name

Is the name of the database for which the compatibility level is to be changed. Database names must conform to the rules for identifiers. name is sysname, with a default of NULL.

[ @new_cmptlevel = ] version

Is the version of SQL Server with which the database is to be made compatible. version is tinyint, with a default of NULL. The value must be one of the following:60 = SQL Server 6.0

65 = SQL Server 6.5

70 = SQL Server 7.0

80 = SQL Server 2000

90 = SQL Server 2005

kaynak: http://msdn.microsoft.com