Restore Database Failed: Exclusive access could not be obtained because the database is in use

Solution 1: Set to single user, then restore
Alter Database [<Database Name>]
  SET SINGLE_USER With ROLLBACK IMMEDIATE

RESTORE DATABASE [<Database Name>] FROM  DISK = N'E:\Databases\SampleDatabase.bak' WITH  FILE = 1,  MOVE N'Tfs_Silverlight' TO N'C:\Program Files\Microsoft SQL Server\MSSQL10_50.MSSQLSERVER\MSSQL\DATA\SampleDatabase.mdf',  MOVE N'SampleDatabase_log' TO N'C:\Program Files\Microsoft SQL Server\MSSQL10_50.MSSQLSERVER\MSSQL\DATA\SampleDatabase.LDF',  NOUNLOAD,  REPLACE,  STATS = 10
GO

Solution 2: Restart SQL Server service
1. Start -> Run and type in services.msc
2. Right click on the SQL Server instance (MSSQLSERVER), click Stop and then Start the service
3. Do the restore process

Basic template for Transactions in Sql Server

SET XACT_ABORT ON;

BEGIN TRY
    BEGIN TRANSACTION;

    -- Code goes here

    COMMIT TRANSACTION;
END TRY
BEGIN CATCH
    IF @@TRANCOUNT > 0
     ROLLBACK TRANSACTION;

    DECLARE
     @ERROR_SEVERITY INT,
     @ERROR_STATE INT,
     @ERROR_NUMBER INT,
     @ERROR_LINE  INT,
     @ERROR_MESSAGE NVARCHAR(4000);

    SELECT
     @ERROR_SEVERITY = ERROR_SEVERITY(),
     @ERROR_STATE = ERROR_STATE(),
     @ERROR_NUMBER = ERROR_NUMBER(),
     @ERROR_LINE  = ERROR_LINE(),
     @ERROR_MESSAGE = ERROR_MESSAGE();

    RAISERROR('Msg %d, Line %d, :%s',
     @ERROR_SEVERITY,
     @ERROR_STATE,
     @ERROR_NUMBER,
     @ERROR_LINE,
     @ERROR_MESSAGE);
END CATCH

Source