ITEC 3220 Lecture Notes - Lecture 1: Saved Game, Database
Document Summary
Transaction is all the reads meaning access and writes meaning insert or update, of database object in database. Read operating will copy from secondary storage to ram. From ram the page goes to the processor. It is important to maintain concurrency usage, multiple users operating on database. As soon as a query is typed, the transaction is initiated by dbms implicitly. To explicitly do it we need to set transaction, commit meaning end of all transaction and save point. If the dbms closed suddenly, transaction is automatically aborted, the rollback command will terminate transaction so the changes will be not implemented on database. Save point command marks the point in the session, all the changes associated with transaction are splatted into two parts, then we can make changes to transaction until certain point therefore being able to define boundary. Ri(o) is read, wi(o) is write, then we have abort, commit and end command.
