Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Explain the Cartesian product:
The Cartesian product operation does not need relations to union-compatible. The meaning of this is that the involved relations may have dissimilar schemas. Let R & S be relations that may have dissimilar schemas.
DEF: Cartesian product
The Cartesian product of relations R and S, denoted R X S, is the set of all probable combinations of tuples of the two operation relations. Every resultant tuple contains all the attributes of R and S.
The resultant relation has
Cardinality = (cardinality of R) * (cardinality of S); and
arity = (arity of R) + (arity of S).
For instance, in given table, STUDENT X MODULE is equal to
Describe an data dictionary? A data dictionary is a data structure which keeps meta data about the structure of the database ie. the schema of the database.
Greater potential for bugs: Since the sites of a distributed system operate simultaneously, it is more complex to ensure the correctness of algorithms. The art of constructing dis
How does a query tree represent a relational algebra expression? Discuss any three rules for query optimisation, giving example as to when should each rule be applied. Ans
If the insertion violates one or more constraints, then two alternatives are available: Default option: - Insertion can be discarded and the reason of refusal can also be ex
What is relational model feature? A relational model feature is much more data independence than some other database models.
Define canonical cover? A canonical cover Fc for F is a set of dependencies like F logically implies all dependencies in FC and Fc logically shows all dependencies in F.
What is DDL? Make a list of commands with short description used in DDL Ans: Data Definition Language that is abbreviated as DDL is a computer language for defining data struct
Explain about database system structure? Storage manager Authorization and integrity manager Transaction manager File manager Buffer manager Storage manager
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 database. A lock can be located
What is a view? How it is related to data independence? A view might be thought of as a virtual table, that is, a table that does not really exist in its own right but is inste
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd