Added \Transactions (fun with transactions)

Transactions/010_transaction_names.sql

+/*
+	According to BOL (http://msdn.microsoft.com/en-us/library/ms188929.aspx) named transactions 
+	must adhere to the rules for identifiers, except names will be truncated at 32 characters.  
+
+	Nothing is mentioned about case-sensitivity.  
+
+	Transaction identifiers are always matched binary.  
+
+*/
+
+--create a case-insensitive db
+CREATE DATABASE TranDemo collate latin1_general_ci_ai
+GO
+USE TranDemo
+GO
+
+CREATE TABLE FooBar (ID int NOT NULL);
+GO
+
+--Test 1:  note the case of the transaction name is different...
+BEGIN TRANSACTION MyTrans
+	INSERT INTO FooBar VALUES (1);
+COMMIT TRANSACTION mytrans
+
+--...however, everything works as we would expect.  
+--this is because transaction name is IGNORED when specified with COMMIT and is solely
+--there to aid readability.  (http://msdn.microsoft.com/en-us/library/ms190295.aspx)
+SELECT @@trancount NumOpenTransactions, ID FROM FooBar
+
+--Test 2:  but this is not the case with ROLLBACK...
+BEGIN TRANSACTION MyTrans
+	INSERT INTO FooBar VALUES (2);
+ROLLBACK TRANSACTION mytrans
+
+--...which will throw an error and leave the transaction open
+SELECT @@trancount NumOpenTxAfterFailedRollback
+
+--rollback the open transaction 
+ROLLBACK;
+
+
+--cleanup
+USE master
+GO
+DROP DATABASE TranDemo;
+GO

Transactions/011_transaction_names.sql

+/*
+	According to BOL (http://msdn.microsoft.com/en-us/library/ms188929.aspx) named transactions 
+	must adhere to the rules for identifiers, except names will be truncated at 32 characters.  
+
+	Committing a named transaction is actually entirely meaningless.  You can commit 
+	any meaningless/non-existent name whatsoever and it works.  The rationale is that 
+	COMMIT will merely decrement @@TRANCOUNT regardless of the name, so the name is
+	simply ignored.  
+*/
+
+--create a case-insensitive db
+CREATE DATABASE TranDemo collate latin1_general_ci_ai
+GO
+USE TranDemo
+GO
+
+CREATE TABLE FooBar (ID int NOT NULL);
+GO
+
+--Test 3:  you can commit any transaction name
+BEGIN TRANSACTION MyTrans
+	INSERT INTO FooBar VALUES (1);
+COMMIT TRANSACTION BlahdyBlah   --this doesn't exist 
+
+SELECT @@trancount TranCount
+SELECT * FROM FooBar
+
+--cleanup
+USE master
+GO
+DROP DATABASE TranDemo;
+GO

Transactions/020_autonomous_tx.sql

+/*
+	Sometimes it would be nice if we had the ability to have "autonomous" transactions
+	like in Oracle  (https://docs.oracle.com/cd/B19306_01/appdev.102/b14261/autonotransaction_pragma.htm)
+
+	An example in SQL Server...logging.  
+
+*/
+
+CREATE DATABASE TranDemo 
+GO
+USE TranDemo
+GO
+
+CREATE TABLE FooBar (ID int NOT NULL PRIMARY KEY CLUSTERED);
+GO
+CREATE TABLE Logger (ID int NOT NULL IDENTITY(1,1) , Msg varchar(200));
+GO
+
+
+--start my batch processing
+BEGIN TRY
+BEGIN TRAN
+	INSERT INTO Logger (Msg) VALUES ('Starting my batch processing.');
+
+	INSERT INTO Logger (Msg) VALUES ('Inserting 1');
+	INSERT INTO FooBar VALUES (1);
+	INSERT INTO Logger (Msg) VALUES ('Inserting 2');
+	INSERT INTO FooBar VALUES (2);
+	INSERT INTO Logger (Msg) VALUES ('Inserting 3');
+	INSERT INTO FooBar VALUES (3);
+	INSERT INTO Logger (Msg) VALUES ('Inserting 1...again');
+	INSERT INTO FooBar VALUES (1);
+	INSERT INTO Logger (Msg) VALUES ('Completed my batch processing.');
+COMMIT
+END TRY
+BEGIN CATCH
+	ROLLBACK TRAN
+	INSERT INTO Logger (Msg) VALUES ('Error occurred during my batch processing');
+END CATCH
+
+--Let's look at Logger
+SELECT * FROM Logger
+
+--cleanup
+USE master
+GO
+DROP DATABASE TranDemo;
+GO

Transactions/021_autonomous_tx.sql

+/*
+	One method to simulate an autonomous transaction is with @TableVariables
+
+*/
+
+CREATE DATABASE TranDemo 
+GO
+USE TranDemo
+GO
+
+CREATE TABLE FooBar (ID int NOT NULL PRIMARY KEY CLUSTERED);
+GO
+CREATE TABLE Logger (ID int NOT NULL, Msg varchar(200));
+GO
+
+--@TableVariables do NOT participate in transaction management
+DECLARE @Logger TABLE (ID int NOT NULL IDENTITY(1,1) , Msg varchar(200));
+
+
+--start my batch processing
+BEGIN TRY
+BEGIN TRAN
+	INSERT INTO @Logger (Msg) VALUES ('Starting my batch processing.');
+
+	INSERT INTO @Logger (Msg) VALUES ('Inserting 1');
+	INSERT INTO FooBar VALUES (1);
+	INSERT INTO @Logger (Msg) VALUES ('Inserting 2');
+	INSERT INTO FooBar VALUES (2);
+	INSERT INTO @Logger (Msg) VALUES ('Inserting 3');
+	INSERT INTO FooBar VALUES (3);
+	INSERT INTO @Logger (Msg) VALUES ('Inserting 1...again');
+	INSERT INTO FooBar VALUES (1);
+	INSERT INTO @Logger (Msg) VALUES ('Completed my batch processing.');
+COMMIT
+END TRY
+BEGIN CATCH
+	ROLLBACK TRAN
+	INSERT INTO @Logger (Msg) VALUES ('Error occurred during my batch processing');
+END CATCH
+
+--FINALLY...update dbo.Logger 
+INSERT INTO Logger SELECT * FROM @Logger
+
+--Let's look at Logger
+SELECT * FROM Logger
+
+--cleanup
+USE master
+GO
+DROP DATABASE TranDemo;
+GO

Transactions/022_autonomous_tx.sql

+/*
+	Another method to simulate an autonomous transaction is with linked servers
+
+*/
+
+CREATE DATABASE TranDemo 
+GO
+USE TranDemo
+GO
+
+CREATE TABLE FooBar (ID int NOT NULL PRIMARY KEY CLUSTERED);
+GO
+CREATE TABLE Logger (ID int NOT NULL IDENTITY(1,1), Msg varchar(200));
+GO
+
+--build a linked server that does not participate in existing transactions
+EXEC sp_addlinkedserver 
+	@server = 'AutonomousLoopback',
+	@srvproduct = N'',
+	@provider = N'SQLNCLI',
+	@datasrc = @@servername;
+EXEC sp_serveroption 
+	@server = 'AutonomousLoopback',
+	@optname = N'RPC OUT',
+	@optvalue = 'TRUE';		--enables RPC
+EXEC sp_serveroption 
+	@server = 'AutonomousLoopback',
+	@optname = N'remote proc transaction promotion',
+	@optvalue = 'FALSE'; --when FALSE then calling a remote stored proc will not start a distributed tx
+GO
+
+--build two Logger stored procs...one does the work, the other is called over the Loopback linked server
+CREATE PROC LogMsgBase @Msg varchar(200)
+AS 
+	INSERT INTO dbo.Logger (Msg) VALUES (@Msg)
+GO
+CREATE PROC LogMsg @Msg varchar(200)
+AS 
+	EXEC AutonomousLoopback.TranDemo.dbo.LogMsgBase @Msg;
+GO
+
+
+--start my batch processing
+BEGIN TRY
+BEGIN TRAN
+	EXEC LogMsg 'Starting my batch processing.';
+
+	EXEC LogMsg 'Inserting 1';
+	INSERT INTO FooBar VALUES (1);
+	EXEC LogMsg 'Inserting 2';
+	INSERT INTO FooBar VALUES (2);
+	EXEC LogMsg 'Inserting 3';
+	INSERT INTO FooBar VALUES (3);
+	EXEC LogMsg 'Inserting 1...again';
+	INSERT INTO FooBar VALUES (1);
+	EXEC LogMsg 'Completed my batch processing.'
+COMMIT
+END TRY
+BEGIN CATCH
+	ROLLBACK TRAN
+	EXEC LogMsg 'Error occurred during my batch processing';
+END CATCH
+
+--Let's look at Logger
+SELECT * FROM Logger
+
+--cleanup
+USE master
+GO
+DROP DATABASE TranDemo;
+GO
+EXEC sp_dropserver @server = 'AutonomousLoopback';

Transactions/030_implicit_tx.sql

+/*
+	In this example SQL Server will help you if you mismatch your BEGIN and COMMIT TRAN statements.
+
+	Neither Wrapper nor CalledProcedure are taking into consideration the fact that other procedures
+	may have altered the open tran count of the workflow.  
+
+	But this behavior does not work when using implicit transactions
+
+	Demo:
+		1)EXEC Wrapper 1 with implicit_transactions OFF...note that Error 266 is thrown
+		2)EXEC Wrapper 0 with implicit_transactions OFF...note that Error 266 is thrown
+		3)EXEC Wrapper 0 with implicit_transactions ON...Error 3902 occurs in Wrapper Procedure
+		3)EXEC Wrapper 1 with implicit_transactions ON...in this case no error is thrown and we "dangled" a transaction
+
+*/
+
+CREATE DATABASE TranDemo 
+GO
+USE TranDemo
+GO
+
+--SET IMPLICIT_TRANSACTIONS ON;
+--GO
+
+CREATE PROCEDURE CalledProcedure @int INT AS 
+BEGIN TRY
+	BEGIN TRAN
+	SELECT 1/@int AS DivisionResult
+END TRY 
+BEGIN CATCH
+	ROLLBACK TRAN
+END CATCH 
+
+--missing COMMIT TRAN statement here
+GO
+
+CREATE PROCEDURE Wrapper @int INT AS 
+BEGIN TRANSACTION
+	EXEC CalledProcedure @int
+COMMIT 
+GO
+
+
+EXEC Wrapper 1
+GO
+
+SELECT @@trancount AS '@@TRANCOUNT'
+
+
+
+--cleanup
+IF @@TRANCOUNT > 0
+	ROLLBACK TRAN 
+GO
+USE master
+GO
+DROP DATABASE TranDemo;
+GO
+SET IMPLICIT_TRANSACTIONS OFF
+GO
\ No newline at end of file

Transactions/031_implicit_tx.sql

+/*
+	Your procedures should always be coded to respect the open transactions that may exist 
+	when the procedure is called and always commit back to that number of open transactions.  
+
+	In some cases we specifically do not want our procedure to be called in the context of an 
+	open transaction.  For example, when batch processing all rows in a table we may only want to 
+	process a few thousand rows at a time to avoid long-duration locking, chances of deadlocking, 
+	and lock escalations.   
+
+	Demo:
+		1)Error:  "BatchProcessing cannot be called in the context of an open transaction"
+		2)Even with SET IMPLICIT_TRANSACTIONS ON everything works correctly.  (Line 63-64)
+		3)But does not function correctly without the wrapper (Line 70-71).  Note that we have 2
+			transactions.  
+
+	http://msdn.microsoft.com/en-us/library/ms187807(v=sql.100).aspx :  states that a 
+	SELECT will start a transaction if one does not already exist when a SELECT is encountered.
+	But this is not true, see Lines 46-48.  Instead you must SELECT from an actual table.  
+	032_implicit_tx.sql has one possible fix.  
+
+*/
+
+CREATE DATABASE TranDemo 
+GO
+USE TranDemo
+GO
+
+--create and populate a test table with 10,000 rows
+CREATE TABLE BigTable (ID int NOT NULL, Processed BIT NOT NULL);
+;WITH TenRows(n) AS
+(
+	SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
+	SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 
+),
+OneHundredRows(n) AS (SELECT 1 FROM TenRows CROSS JOIN TenRows b),
+OneThousandRows(n) AS (SELECT 1 FROM OneHundredRows CROSS JOIN OneHundredRows b)
+INSERT INTO BigTable (ID, Processed)
+SELECT ROW_NUMBER() OVER(ORDER BY n) AS ID , 0 AS Processed FROM OneThousandRows ;
+GO
+
+--we want to set the Processed flag to 1 for 2000 rows at a time. 
+--this procedure should be written better to avoid locking problems, but we 
+--merely want to demo how transaction handling works.   
+CREATE PROCEDURE BatchProcessing AS 
+
+DECLARE @TRANCOUNT INT
+SELECT @TRANCOUNT = @@TRANCOUNT 
+IF @TRANCOUNT <> 0 
+BEGIN
+	RAISERROR ('BatchProcessing cannot be called in the context of an open transaction',16,1)
+	RETURN 1
+END 
+
+WHILE EXISTS (SELECT 1 FROM BigTable WHERE Processed = 0)
+BEGIN
+	BEGIN TRAN	
+		SELECT @@trancount AS 'TranCount in Loop'
+		UPDATE TOP (2000) BigTable SET Processed = 1 WHERE Processed = 0
+	COMMIT TRAN
+END;
+
+GO
+
+CREATE PROCEDURE Wrapper AS 
+BEGIN TRANSACTION
+	EXEC BatchProcessing
+COMMIT 
+GO
+
+--SET IMPLICIT_TRANSACTIONS ON;
+--GO
+
+EXEC Wrapper 
+GO
+
+--EXEC BatchProcessing
+--GO
+
+
+--cleanup
+IF @@TRANCOUNT > 0
+	ROLLBACK TRAN 
+GO
+USE master
+GO
+DROP DATABASE TranDemo;
+GO
+SET IMPLICIT_TRANSACTIONS OFF
+GO
\ No newline at end of file

Transactions/032_implicit_tx .sql

+/*
+	http://msdn.microsoft.com/en-us/library/ms187807(v=sql.100).aspx :  states that a 
+	SELECT will start a transaction if one does not already exist when a SELECT is encountered.
+	But this is not true.  This builds on 031_implicit_tx.sql.  
+
+	See the new code for Lines 33-35.  
+
+*/
+
+CREATE DATABASE TranDemo 
+GO
+USE TranDemo
+GO
+
+--create and populate a test table with 10,000 rows
+CREATE TABLE BigTable (ID int NOT NULL, Processed BIT NOT NULL);
+;WITH TenRows(n) AS
+(
+	SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
+	SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 
+),
+OneHundredRows(n) AS (SELECT 1 FROM TenRows CROSS JOIN TenRows b),
+OneThousandRows(n) AS (SELECT 1 FROM OneHundredRows CROSS JOIN OneHundredRows b)
+INSERT INTO BigTable (ID, Processed)
+SELECT ROW_NUMBER() OVER(ORDER BY n) AS ID , 0 AS Processed FROM OneThousandRows ;
+GO
+
+--we want to set the Processed flag to 1 for 2000 rows at a time. 
+--this procedure should be written better to avoid locking problems, but we 
+--merely want to demo how transaction handling works.   
+CREATE PROCEDURE BatchProcessing AS 
+
+DECLARE @TRANCOUNT INT
+--SELECT @TRANCOUNT = @@trancount
+SELECT TOP 1 @TRANCOUNT = @@TRANCOUNT FROM sys.objects  
+IF @TRANCOUNT <> 0 
+BEGIN
+	RAISERROR ('BatchProcessing cannot be called in the context of an open transaction',16,1)
+	RETURN 1
+END 
+
+WHILE EXISTS (SELECT 1 FROM BigTable WHERE Processed = 0)
+BEGIN
+	BEGIN TRAN	
+		SELECT @@trancount AS 'TranCount in Loop'
+		UPDATE TOP (2000) BigTable SET Processed = 1 WHERE Processed = 0
+	COMMIT TRAN
+END;
+
+GO
+
+--CREATE PROCEDURE Wrapper AS 
+--BEGIN TRANSACTION
+--	EXEC BatchProcessing
+--COMMIT 
+--GO
+
+SET IMPLICIT_TRANSACTIONS ON;
+GO
+
+--EXEC Wrapper 
+--GO
+
+EXEC BatchProcessing
+GO
+
+
+--cleanup
+IF @@TRANCOUNT > 0
+	ROLLBACK TRAN 
+GO
+USE master
+GO
+DROP DATABASE TranDemo;
+GO
+SET IMPLICIT_TRANSACTIONS OFF
+GO
\ No newline at end of file

Transactions/033_implicit_tx.sql

+/*
+	This further demos how to check if you are running under 
+	implicit transactions (IT) and some of the consequences 
+	of doing so.  
+
+*/
+
+CREATE DATABASE TranDemo 
+GO
+USE TranDemo
+GO
+
+SELECT 'Let''s set up a test.  Clean up my env.' AS Message
+SET IMPLICIT_TRANSACTIONS OFF
+IF @@TRANCOUNT > 0 ROLLBACK TRAN
+
+SELECT 'IT should be OFF and my @@trancount should be 0' AS Message
+SELECT CASE (2 & @@OPTIONS) WHEN 2 THEN 'ON' ELSE 'OFF' END AS [IT Status], @@trancount AS [@@trancount]
+
+SET IMPLICIT_TRANSACTIONS ON
+SELECT 'Turn on IT and doublecheck that @@OPTIONS is set correctly' AS Message
+SELECT CASE (2 & @@OPTIONS) WHEN 2 THEN 'ON' ELSE 'OFF' END AS [IT Status]
+
+SELECT 'TEST 1: IT ON, what is my trancount?  Should be zero, because I did no work yet' AS Message
+SELECT 'This runs contrary to:  http://msdn.microsoft.com/en-us/library/ms187807(v=sql.100).aspx'
+SELECT getdate() AS [a random SELECT]
+SELECT @@TRANCOUNT AS [@@trancount before querying a real table]
+SELECT 'TEST 2: SELECT must have a FROM clause to start an implicit transaction.'
+--The mere act of querying a "real table" causes a transaction to become "active"
+	select @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+
+SELECT 'TEST 3: Start an explicit transaction.  @@trancount is now 2.'
+SELECT 'But note that we do not see DMV rows for EVERY transaction'
+BEGIN TRAN 
+	select @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+
+
+SELECT 'ROLLBACK and start over.  Verify IT status and trancount'
+ROLLBACK TRAN 
+SELECT CASE (2 & @@OPTIONS) WHEN 2 THEN 'ON' ELSE 'OFF' END AS [Status of IT],@@TRANCOUNT [TranCount]
+
+SELECT 'TEST 4:  impl_tran on with nested user tran, DMV results are unexpected'
+set implicit_transactions ON
+	select 'Impl_tran ON only' AS [Test 4a], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+BEGIN TRAN
+	select 'Impl_tran ON with one user tran' AS [Test 4b], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+BEGIN TRAN MyNamedTransaction
+	select 'Impl_tran ON with two user trans' AS [Test 4c], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+if @@trancount > 0 rollback
+
+SELECT 'TEST 5:  What do the DMVs look like without using IT?'
+set implicit_transactions OFF
+	select 'Without a transaction' AS [Test 5a], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+BEGIN TRAN
+	select 'With one transaction' AS [Test 5b], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+BEGIN TRAN
+	select 'With two transactions' AS [Test 5c], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+if @@trancount > 0 rollback
+
+SELECT 'TEST 6:  What do the DMVs look like when I use named transactions'
+set implicit_transactions OFF
+	select 'Without a transaction' AS [Test 6a], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+BEGIN TRAN MyOuterTransaction
+	select 'With one transaction' AS [Test 6b], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+BEGIN TRAN MyInnerTransaction
+	select 'With two transactions' AS [Test 6c], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+if @@trancount > 0 rollback
+
+--so the rule seems to always be to show implicit_transaction when that is ON, else show the outermost user_transaction name (or just user_transaction if there is no name)
+--...or is this the rule?
+--let's see what happens with "marked transactions"
+
+SELECT 'TEST 7:  impl_tran OFF/nested "marked" user tran, expect OuterNamedTran'
+set implicit_transactions OFF
+begin tran OuterNamedTran WITH MARK 'OuterMark'
+begin tran InnerNamedTran WITH MARK 'InnerMark'
+	select 'Marked Transactions' AS [Test 7], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+if @@trancount > 0 rollback
+
+SELECT 'TEST 8:  impl_tran ON with marked transactions'
+set implicit_transactions ON
+begin tran OuterNamedTran WITH MARK 'OuterMark'
+	select 'OuterNamedTran and mark' AS [Test 8a], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+begin tran InnerNamedTran WITH MARK 'InnerMark'
+	select 'InnerNamedTran and mark' AS [Test 8b], @@TRANCOUNT AS [@@trancount],tat.name [dm tran name], tst.is_user_transaction,CASE WHEN tat.transaction_state = 2 THEN 'Active' END AS transaction_state, tat.transaction_status2  
+	from sys.dm_tran_active_transactions tat, sys.dm_tran_session_transactions tst 
+	where tat.transaction_id = tst.transaction_id and tst.session_id = @@spid 
+if @@trancount > 0 rollback
+
+/*
+So the rule is that sys.dm_tran_active_transactions returns the "name" of the OUTER transaction (or implicit_transaction) and never any rows for the inner transactions as
+long as transaction_status2 = 258 (which, I guess means non-marked transactions).  When a transaction is marked then sys.dm_tran_active_transactions returns the outer most
+named and marked transaction, regardless of whether there is an implicit_transaction.  We can deduce this because transaction_status2= 266 (which I guess means HasMarkedTransaction
+transaction_status2 is not supported and future compatibility is not guaranteed.
+*/
+
+
+--cleanup
+IF @@TRANCOUNT > 0
+	ROLLBACK TRAN 
+GO
+USE master
+GO
+DROP DATABASE TranDemo;
+GO
+SET IMPLICIT_TRANSACTIONS OFF
+GO
\ No newline at end of file

Transactions/README.MD

+Transaction Trivia
+
+Did you ever notice that sp_reset_connection is called A LOT? 
+Did you ever see an "orphaned spid" with an open transaction that caused you massive blocking? 
+Do you run jdbc or dblib data access technologies? 
+Have you ever had @@TRANCOUNT show an incorrect value?  
+Wouldn't it be nice to spin up a autonomous "auditing" transaction in the middle of your main transaction 
+that will not be rolled back?  If you answered yes to any of these then you are ready to delve deeper 
+into SQL Server transactions. You may be surprised that transaction handling doesn't always work the 
+way you think it does.
+
+`FunWithTransactions.pptx` : Presentation file.