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.
Describe the four main ways of optimising disk block access. Ans: a. Disk b. Non-volatile writes buffers c. File organization (Clustering) d. Log-based file system
Question 1 Discuss the classification of DBMS based on location of database Question 2 Explain with examples different SQL commands used for creating and deleting relations.
What are the key features of Oracle? Key features of Oracle are as follows: • Read Consistency • Concurrency • Locking Mechanisms • Quiesce Database • RAC • Portability
Define raid? Briefly explain it? A range of disk organization methods, collectively called redundant arrays of independent disks (RAID) o Improvement of reliability throug
Now that she understands more about the benefits of databases, the play-scheme manager would like to extend the play-scheme database to include data for schools and instructors as
Compare the Nested-loop join and block-nested loop join Ans: Nested loop join - It is costly as worst case cost, no. of block accesses needed is n r * b s + b r where b
Question 1 Explain the concept of Foreign Key. How a foreign key differs from a Primary Key? Can the Foreign Key accept nulls? Question 2 With a necessary example explain (i)
Define seek time. The time for repositioning the arm is known as the seek time and it enhances with the distance that the arm is known as the seek time.
Events4Fun is an event management company in Europe with branches in South America as well. The company is well-known for its efficiency, good-quality services, and affordable char
A relation has: Relational Schema Relation instance Relational Schema: A relational schema shows the relation's name, its attributes and the domain of every a
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