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!
In a relation, tuples are not inserted in any definite order. Ordering of tuples is not defined as a part of a relation definition. Though, records may be structured later according to some attribute value in the storage systems. For instance, records in PERSON table may be structured according to PERSON_ID. Such organisation or data depends on the requirement of the underlying database application. Though, for the purpose of display we may get them displayed in the sorted order of age. The following table is sorted by age. It is also worth states here that relational model does not permit duplicate tuples
PERSON
PERSON_ID NAME AGE ADDRESS
2 Sharad Gupta 33 Pocket 2, Mayur Vihar.
1 Sanjay Prasad 35 b-4,Modi Nagar
3 Vibhu Datt 36 c-2, New Delhi
Super Keys, Candidate Keys and Primary Keys for the Relations
As discussed in the last section ordering of relations does not matter and all tuples in a relation are unique. Though, can we uniquely recognize a tuple in a relation? Let us talk about the concepts of keys that are primarily used for the purpose as above.
Benefits: It limits data access. It makes difficult queries look easy. It permits data independence. It presents dissimilar views of the similar data.
What is object containment? References among objects can be used to model dissimilar real-world concepts.
What are the two types of indices? The two types of indices are:- A) Dense index B) Sparse index
Define garbage collection. Garbage may be formed also as a side effect of crashes. Periodically, it is essential to find all the garbage pages and to add them to the list of fr
construct an er diagram for a hospital with a set of patients and a set of medical doctors. associate with each patient a log of various test and examination conducted.convert er d
Describe five main functions of a database administrator. Ans: A database administrator (DBA) is a person who is accountable for the environmental aspects of a database. Genera
The Database Approach In order to overcome the limits of a file system, a new approach was needed. Hence a database approach emerged. A database is a persistent collection of
Developer is required to do a task including: - Database Normalization - Database Analysis - ERM Diagram Details can be provided and then you can change your bid accord
What is meant by mean time to failure? The mean time to failure is the amount of time that the system could run continuously without failure.
What is foreign key? A relation schema r1 derived from an ER schema may contain among its attributes the primary key of another relation schema r2.this attribute is known as 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