SQL Server 2008: Making Database read only & changing it to read/write

Here is a way to alter the database to ready only and making it back to read/write.

Make Database Read Only

USE [master]
GO
ALTER DATABASE [TESTDB] SET READ_ONLY WITH NO_WAIT
GO

Make Database Read/Write

USE [master]
GO
ALTER DATABASE [TESTDB] SET READ_WRITE WITH NO_WAIT
GO