To bring a SQL Server database online or offline you can use a command like the following if your database is named test.

sql ALTER DATABASE test SET OFFLINE;

ALTER DATABASE test SET ONLINE;


When running SQL Server on Amazon's Relational Database Service it is done a little different. While you can use the command above to take the database offline, you can't use the command to bring the database online.

I you have a database name test and you execute the following it will work

sql
ALTER DATABASE test SET OFFLINE

You can verify this by running the following

sql USE test GO


You get the following error

_Msg 942, Level 14, State 4, Line 1
  
Database 'test' cannot be opened because it is offline._

If you try running the following command to bring the database online

sql
ALTER DATABASE test SET ONLINE;

Now you get this error

_Msg 5011, Level 14, State 9, Line 1

User does not have permission to alter database ‘test’, the database does not exist, or the database is not in a state that allows access checks.

Msg 5069, Level 16, State 1, Line 1

ALTER DATABASE statement failed._

So what can you do? RDS has a special stored procedure that will bring the databse online, the name of this stored procedure is rdsadmin.dbo.rds_set_database_online

Here is how you use it

sql EXEC rdsadmin.dbo.rds_set_database_online ‘test’ GO


Now you can use the test database again

sql
USE test
GO

See, simple, you just have to be aware of these differences