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define the two phase locking protocol this is a protocol that is used to make sure serializability of transactions this protocol needs that every
define deadlock avoidance these protocols as well ensure that the system will never enter a deadlock state although the way it is done is different
define deadlock detection if a system does not employ a few protocols that make sure deadlock freedom after that a detection and recovery scheme
define deadlock prevention these protocols make sure that the system will never enter a deadlock state there are two methods to deadlock prevention
define two phase committwo phase commit to make sure atomicity all the sites where a transaction is being executed must agree on the final outcome of
define thomas write rulethomas write rule the thomas write rule is a modification of timestamp-ordering protocol for concurrency control assume that
what is a hashing function what are the properties of a good hashing function describe the folding technique for hashing functions
define serializable scheduleserializable schedule an interleaved schedule of much more than one transaction is known as a serializable schedule if it
define shared locksans shared lock throughout concurrent execution of transactions earlier than a transaction can access a data item it has to obtain
how does a query tree represent a relational algebra expression discuss any three rules for query optimisation giving example as to when should
what are the three data anomalies that are likely to occur as a result of data redundancy can data redundancy be completely eliminated in
define the terms entity attribute role and relationship between the entities giving examples for each of them ans
define physical and logical data independence how does this architecture help in achieving thesedata independence entails that change in one view
q1 briefly discuss the different layers of ansi sparc architectureans the three layers of ansi sparc architecture are like this1 internal view is at
define what are the desirable properties of a decompositionans what are the desirable properties of decomposition - dependency preserving because
what is data integrityans it is the data consisted of in database that is accurate and consistent data integrity means that the data should be
define in which normalisation form if an attribute of a composite key is dependent on an attribute of other composite keyans 3nfa relation is in 3 nf
define an abstraction by which relationships are treated as higher level entitiesans aggregation it is an abstraction by which relationships are
define according to the levels of abstraction the schema at the intermediate level is called ans as per to the levels of abstraction the schema at
what is a disjoint less constraintans it needs that an entity belongs to no much more than one level entity set disjoint less constraint needs
the clause in sql which specifies that the query result should be sorted in ascending or descending order based upon the values of one or much more
determine the rule that a value of a foreign key should appear as a value of some particular table is called a ans referential constraint
determine the language that needs a user to specify the data to be retrieved with no specifying exactly how to get it isans non-procedural
1 which model is used to store data in tree structuresans hierarchical model is used to store data in tree
1 determine that the checkpoints are a part of ans checkpoints are a part of recovery