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
To eliminate duplicate rows (distinct operator) Example: SELECT DISTINCT DEPTNO FROM EMP;
The Conceptual Level or Global level The conceptual level presents a logical view of the complete database as a unified whole. It permits the user to bring all the data in th
Prove that a relation which is 4NF must be BCNF. Ans Let R be in 4NF. Suppose it is not in BCNF. Hence, there exists an FD X→Y in R such that x is not a super key. Although
The following variant of the primary copy asynchronous-update replication protocol has been proposed for totally replicated systems. (a) A transaction executing at site A updat
Speedup Query Processing: A query that includes data at various sites can be split into sub-queries. These sub- queries can be implemented in parallel by various sites. Such parall
A domain is a set of permissible values that can be given to an attribute. So each attribute in a table has a definite domain. Values to these attributes cannot be assigned outside
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
FDs in Entities : Student entity : Enrolment number → Student name, Address Course Entity :
Data Base Management System 1. Draw the Architecture of MySQL and explain about its subsystems briefly. 2. Elaborate with the help of an example the concept of Primary key a
What is an entity relationship model? The entity relationship model is a collection of basic objects known as entities and relationship between those objects. An
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