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1 develop a flowchart using the decision structure to solve the following problema box lunch bonanza is a small catering company that offers 2
failures and recoveryin practice various things might occur to prevent a transaction from completing recovery methods are used to bring database
what is recovery during the life of a transaction ie a after the start of a transaction but before the transaction commits various changes may be
objectives define the terms recovery and integrity define recovery techniques explain error and error detection techniques and define types of
database recovery and securityintroductionin this part we will introduce two main issues relating to database management systemsa computer system
read-sett each data items that are read by a transaction ttimestamps for all transaction t the start-time and the end time are reserved for all the
optimistic concurrency controlis locking the only way to stop concurrency related problems there exist some other ways too one such way is known as
deadlock preventionone of the easiest approaches for avoiding a deadlock would be to obtain all the locks at the begin of the transaction though this
normalize the following tables upto and including the 3nf submit a 1 page printout of only the final set of normalized tables in data architect just
two phase locking 2plthe two-phase locking protocol having of two phasesphase 1 the lock acquisition phase if a transaction t needs to read an object
exclusive lock it is asked for by a transaction on a data item that it wants to update no other transaction can put either a shared lock or an
normalize the following table upto and including the 3nf submit a 1 page printout of only the final set of normalized tables in data architect just
shared lock or read lock it is requested by a transaction that needs to just read the value of data item a shared lock on a data item does not permit
multiple-mode locks it offers two locks exclusive locks and shared locks but why do we require these two locks there are a lot of transactions in the
types of locksthere are two necessary types of locks binary lock this locking mechanism has two states for to a data item locked or unlocked
locksserialisabilty is just a test whether a given interleaved schedule is ok or has a concurrency related trouble though it does not make sure that
you group has been hired by trainingruscom to keeps track of training revenues trainingruscom wants you to keep schedulingcourse table contains
serialisable schedulesif the processes of two transactions conflict with each other how to verify that no concurrency related problems have happened
the locking protocol to manage concurrency related problems we use locking a lock is mainly a variable that is associated with a data item in the
inconsistent analysis the problem as given with transactions t1 and t2 where two transactions interleave to make incorrect result during an analysis
dirty reads t10 reads a value which is updated by t9 this update has not been committed and t9 abortst9t10value of x old value 200t9t10update
unrepeatable reads assume t7 reads x twice during its implementation if it did not update x itself it could be very disturbing to see a dissimilar
lost updates suppose the two transactions t3 and t4 run simultaneously and they happen to be interleaved in the following way suppose the initial
conflicting operations in schedulethe three simple ways of interleaved instruction implement of transactions t1 and t2 please note that in the
step 1 using oracle create the tables identified in the preferred solution for assignment 2 technicians zipcode technicianid firstname lastname