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.
Describe the development process of Object oriented methods Object oriented methods have roots which are strongly anchored back in the 60s, functional and structured methods we
sir, could anybody help me in getting complete information about the mentioned topic
what is meant semantic query optimization? how does it differ from other query optimization techniques?
Greater potential for bugs: Since the sites of a distributed system operate simultaneously, it is more complex to ensure the correctness of algorithms. The art of constructing dis
With the help of a diagram defines the typical element modules of a DBMS? The functional elements of a database system can be widely divided into: 1) Storage manager and 2) q
Explain the disadvantages of a file processing system? Ans: Disadvantages of File Processing Systems include: 1) Data Redundancy 2) Data Inconsistency 3) Difficult to acce
how the string works as keyword?
Define the Third Normal Form: The third normal form (3NF) is a normal form employed in database normalization. 3NF was initially defined by E.F. Codd in 1971. Codd's definitio
explain multi key file organisation
i want help to complete my task
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