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:
UNION If R1 and R2 are two union compatible relations then R3 = R1 ∪ R2 is the relation having tuples that are either in R1 or in R2 or in both. In case, R3 will have tuples
East Coast Aquarium Relational Database
What is the use of rename operation? Rename operation is used to rename both relations and an attributes. It uses the as clause, taking the form: Old-name as new-name.
What is a view? How it is related to data independence? A view might be thought of as a virtual table, that is, a table that does not really exist in its own right but is inste
what are the topics in data management
Determine the benefits of Object oriented design OOD also gives reusability, which saves time, costs and productivity gains through direct mapping to properties of Object-Orie
Express the ways provided by MySQL for Pattern Matching? MySQL provides two kinds of pattern matching. 1) One is based on SQL patterns 2) Regular expressions.
State the Design of Associations Before designing associations, it is essential to know the way they are used. For this, analysis of association traversals is required. It is
what is entity in database system?
Illustrate the Deployment Diagram A deployment diagram shows all nodes on network, their processor execution and interconnections. In a dynamic model, this is used to represen
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