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!
It defines that no primary key value can be null. This is as the primary key is used to recognize individual tuple in the relation. So we will not be able to recognize the records uniquely containing null values for the primary key attributes. This constraint is specified on single individual relation.
Example: Let R be the Table
A#
B
C
Null
B1
C1
A2
B2
C2
B3
C3
A4
B4
A5
C5
Note:
1) '#' shows the Primary key of a relation.
In the relation R above, the primary key has null values in the tuples t1 & t3. NULL value in primary key is not allowed, therefore, relation instance is an invalid instance.
OBJECTIVES After going through this unit you should be capable to: Explain the File Based system and its limitations; Explain the structure of DBMS; Explain the
Competition entrants can be either Individuals, or Teams. A Team is usually sponsored by a business, and, in that case, the team members would all wear T-shirts with the sponsoring
Assigning Responsibility for Operation Many operations might have obvious target objects, but some of these operations could be used at numerous places in an algorithm, by one
intent locking
PHYSICAL DBMS ARCHITECTURE The physical architecture defines the software components used to process and enter data, and how these software components are related and interc
what is query processing ,query optimization and performance turring?
What is Structured Query Langauge (SQL)? SQL is a powerful set-oriented language which was formed by IBM research for the databases that adhere to the relational model. It havi
Question: In relation to distributed database answer the following questions: (i) Give a brief definition of distributed database. Support your answer with an appropriate di
What is the difference between serial and sequential files? How searching is applied on both? Ans: A serial file is one where the records have been stored in the order where
Update Anomaly : This anomaly is occurred due to data redundancy. Redundant information makes updates more complex since, for example, varying the name of the instructor of MCS-014
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