SQL Server 2005 transaction locks

Utilizing the Dynamic Management Views is the best and easier way to do it ...

SELECT L.request_session_id AS SPID,
   DB_NAME(L.resource_database_id) AS DatabaseName, 
   O.Name AS LockedObjectName, 
   P.object_id AS LockedObjectId, 
   L.resource_type AS LockedResource, 
   L.request_mode AS LockType, 
   ST.text AS SqlStatementText, 
   ES.login_name AS LoginName, 
   ES.host_name AS HostName, 
   TST.is_user_transaction as IsUserTransaction, 
   AT.name as TransactionName, 
   CN.auth_scheme as AuthenticationMethod 
FROM sys.dm_tran_locks L 
   JOIN sys.partitions P ON P.hobt_id = L.resource_associated_entity_id 
   JOIN sys.objects O ON O.object_id = P.object_id 
   JOIN sys.dm_exec_sessions ES ON ES.session_id = L.request_session_id 
   JOIN sys.dm_tran_session_transactions TST ON ES.session_id = TST.session_id 
   JOIN sys.dm_tran_active_transactions AT ON TST.transaction_id = AT.transaction_id 
   JOIN sys.dm_exec_connections CN ON CN.session_id = ES.session_id 
   CROSS APPLY sys.dm_exec_sql_text(CN.most_recent_sql_handle) AS ST 
WHERE resource_database_id = db_id() 
   ORDER BY L.request_session_id 

sys.dm_tran_locks:

Shows us all locks held on all resources for all transaction. We start from this view since we want to get information about locked resources.

sys.partitions:

Contains information about partitions in the database. We can join it to the sys.dm_tran_locks on the hobt_id only for resource_type values 'HOBT', 'Page', 'RID'  and 'Key'. With this join we get the object_id of our locked table.

sys.objects:

Contains data for all schema scoped database objects. We join it to sys.partitions to get the Name of the locked object which is usually a table name.

sys.dm_exec_sessions:

Shows data about all active sessions on SQL server. We join it to sys.dm_tran_locks to get user login information for each held lock.

sys.dm_tran_session_transactions:

Shows data for all transactions for a session. By joining in to sys.dm_exec_sessions we get a link to all active transactions in the session.

sys.dm_tran_active_transactions:

Shows data for all active transactions in SQL Server. By joining it to sys.dm_tran_session_transactions we only get information for the session we want.

sys.dm_exec_connections:

Shows data for all connections in SQL Server. By joining it to sys.dm_exec_sessions we get connection info for our session.

sys.dm_exec_sql_text:

Returns SQL statement that is associated with the SQL handle input parameter. By cross applying it to the sys.dm_exec_connections we get the last executed statement for the connection, which in our case is the statement that is holding locks.