Transaction allows a set of T-SQL statements to be executed together as a single unit. Transactions have ACID properties - Atomicity, Consistency, Isolation, and Durability. There are three types of transactions: autocommit, implicit, and explicit. Autocommit commits each statement individually while implicit and explicit transactions require COMMIT or ROLLBACK statements. SAVEPOINT allows rolling back to points within explicit transactions without rolling back the entire transaction.

1. Transaction

2. Whatistransaction?
IsasetofT-SQLstatementsthatareexecutedtogetherasaunitlikeasa
singleT-SQLstatement.IfalloftheseT-SQLstatementsexecuted
successfully,thenatransactioniscommittedandthechangesmadebyT-SQL
statementspermanentlysavedtodatabase

3. Transactionproperties(ACID)
Atomicity.Associatedmodificationsareanall-or-nothingproposition;eitherallare
doneornonearedone.
requiresthateachtransactionbe"allornothing":ifonepartofthetransactionfails,
thentheentiretransactionfails
Consistency.Afteratransactionfinishes,alldataisinthestateitshouldbein,all
internalstructuresarecorrect,andeverythingaccuratelyreflectsthetransactionthat
hasoccurred.
Isolation.Onetransactioncannotinterferewiththeprocessesofanothertransaction.
Durability.Afterthetransactionhasfinished,allchangesmadearepermanent.

4. Typeoftransaction
1. Autocommit
2. Implicittransaction
3. Explicittransaction

5. AutoCommit.EverySQLstatementisitsowntransactionandautomatically
commitswhenitfinishes.ThisisthedefaultmodeinwhichDBServeroperates.
Explicittransaction: Thisapproachprovidesprogrammaticcontrolofthe
transaction,usingtheBEGINTRANandCOMMIT/ROLLBACKTRAN/WORK
commands.
ThemaindifferencebetweenImplicitandExplicittransactionisthatimplicit
transactionisauto,controlledbySQLServerEngineandstatementlevel
transaction,whereasexplicittransactionisuserdefinedandbatch-scoped
transaction

6. Implicittransaction:
Inthismode,whenyouissuecertainSQLcommands,DBServer
automaticallystartsatransaction.Youmustfinishthetransactionby
explicitlyissuingtheCOMMIT/ROLLBACKTRAN/WORKcommands.
everyDDL(CREATE,ALTER,DROP,TRUNCATE),DML(INSERT,
UPDATE,DELETE)statements.AlltheseT-SQLstatementsrunsunderthe
implicittransaction

7. Transaction control
COMMIT:tosavethechanges.
ROLLBACK:torollbackthechanges.
SAVEPOINT:createspointswithingroupsoftransactionsinwhichtoROLLBACK

8. Thecommitcommand
•TheCOMMITcommandisthetransactionalcommandusedtosave
changesinvokedbyatransactiontothedatabase.
•TheCOMMITcommandsavesalltransactionstothedatabasesincethelast
COMMITorROLLBACKcommand

9. The Rollback command
•TheROLLBACKcommandisthetransactionalcommandusedtoundo
transactionsthathavenotalreadybeensavedtothedatabase.
•TheROLLBACKcommandcanonlybeusedtoundotransactionssincethe
lastCOMMITorROLLBACKcommandwasissued.

10. The save point
•ASAVEPOINTisapointinatransactionwhenyoucanrollthetransaction
backtoacertainpointwithoutrollingbacktheentiretransaction.

11. Syntax transaction
• BEGINTRAN[SACTION]
• Statement1
• Statement2
• etc…
• COMMIT[TRAN[SACTION]
OR
• ROLLBACK[TRAN[SACTION]

12. Example:-

13. ThankU4Discussing