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 algorithm of ER To Relational Mapping ?
ER-to-Relational Mapping Algorithm:
1) Step 1: Mapping of regular entity types: For each strong entity type E, form a relation T which involves all the easy attributes of a composite attribute.
2) Step2: Mapping of weak entity types: For each weak entity type W along with owner entity type E, create relation R and involve all easy attributes (or simple components of composite attributes) of W as attributed of R. In addition, involves as foreign key attributes of R, the primary key attribute (s) of relation(s) which correspond to the owner(s) and the partial key of the weak entity type W, if any.
3) Mapping of relationship types: form a relation R, for relationship along with primary keys of participating relations A and B as foreign keys in R. Further to this, any attributes of relationship become an attribute of R also.
4) Mapping of multivalued attributes: For every multilvalued attribute A, form a new relation R. This relation R will involve an attribute corresponding to A, plus primary key attribute K-as a foreign key in R-of the relation which represents the entity category or relationship type that has A as an attribute.
Define tuple variable? Tuple variables are used for comparing two tuples in the same relation. The tuple variables are explained in the from clause by way of the as clause.
What is candidate key? Candidate Key - A candidate key of an entity set is a minimal superkey, which uniquely identifies each row in the relation.
Difference between LEFT OUTER JOIN and RIGHT OUTER JOIN In left outer join tuples from the left-hand-side relation which do not match any tuple in the right-hand-side relation
find the name of supplier who supply some red part
Views in relational algebra: 1. Basic expression contains either a) A relation in the database. b) A constant relation. 2. General expressions are madde out of sma
Given the following relations TRAIN (NAME, START, DEST) TICKET (PNRNO., START, DEST, FARE) PASSENGER (NAME, ADDRESS, PNRNO.) Write SQL expressions for the following queries: No
Database Manager It is the interface among low-level data, queries and application programs. Databases typically need a large amount of storage space. It is kept on disks, as
discuss the purpose of the concurrency control?
I am going to develop a web site to present decision tree structure. For this, I want a web application with AJAX technology to connect the database and prepare the decision tree's
Define the Canonical cover Ans: A canonical cover F c for F is a set of dependencies like F logically implies all dependencies in F c , and F c logically entails all dependen
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