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!
This constraint shows that the key attribute value in each tuple must be unique, i.e., no two tuples have the similar value for the key attribute. This is because the value of the primary key is used to recognize the tuples in the relation.
Example: If A is the key attribute in the following relation R than A1, A2 and A3 must be unique.
A
B
A1
B1
A3
B2
A2
Example: In relation PERSON, PERSON_ID is primary key so PERSON_ID cannot be given as the similar for two persons.
Integrity Constraint
There are two kinds of integrity constraints:
" Wound-wait" scheme : It is based on a preemptive method. It is based on a simple rule: If Ti requests a database resource that is held by Tj
NEED ER DIAGRAM WITH MINIMUM ENTITY AND RELATIONSHIP of Hospital Management System
explain ER Modeling?
Process to find the non-concurrent objects Once we find out non-concurrent (mutually exclusive) objects, we can fold all objects together in one thread of process or control. O
Aggregation : One limitation of the E-R diagram is that they do not permit representation of relationships between relationships. In such a case the relationship along with its ent
Although, the essential features of E-R diagrams are enough to design many database situations. Though, with more difficult relations and advanced database applications, it is need
A Structure of a dependency diagram
Question 1 What do you mean by database management system? Question 2 Write a note on Object-Oriented Model Question 3 Explain Sequential File Organization Question
Using the concepts defined previous, we have identified that strong entities in COLLEGE database are FACULTY, STUDENT, COURSE and DEPARTMENT. This database also has one weak entity
What does Aggregation mean?
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