Is it possible to upgrade a SQL Server 2000 database to 2005 without knowing it?

Is it possible to upgrade a SQL Server 2000 database to SQL Server 2005 in-place without knowing you did it? In other words, can this upgrade happen accidentally?

We had an incident today. Our application just stopped working. We requested 开发者_运维百科the consultant modify a stored procedure and within a few hours, the phone started ringing... no one could access our app and those that were able to, could not access SSRS.

Fast forward a few hours and many emails between all the players, the consultant concluded the database was upgraded to 2005.

If you're speaking of the SQL Server instance, then no. That takes a lot of effort, multiple steps, with Administrative credentials on the Windows machine.

If you're speaking of the database's compatibility level, then yes. All it takes is a few clicks in SSMS (Properties-Options-Compatibility level), or a one-liner of TSQL. It'd require db_owner credentials.

ALTER DATABASE MyDatabase SET COMPATIBILITY_LEVEL = 90;

or

sp_dbcmptlevel MyDatabase, 90

There's nothing 'automatic'. Only a script or mis-step in SSMS could 'silently' make this change.