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.
sql is relationally complete-justify
What is a view? Make a view of EMP table named DEPT 20, to display the employees in department 20 and their annual salary. Ans: View is a virtual table that does not consist
State the meaning of Object Representation The term object representation means "to represent object with the help of objects model symbols". Implementing objects is too simp
When a function module is activated syntax checking is performed automatically. YEs, a function module is activated syntax checking.
What is Conceptual Schema? Conceptual Schema - Conceptual schema elaborates the structure of the overall database for a community of users. It hides the details of physical sto
Give the levels of data abstraction? There are three levels of Data Abstraction a) Physical level b) logical level c) view level
Eliminate Repeating Groups The problem is, "Find out the list of employees, who knows DB2". For this problem we require to perform an awkward scan of the list looking for re
NEED FOR A DATABASE MANAGEMENT SYSTEM A Database is a structured, persistent collection of data of an organisation. The database management system (DBMS) manages the database o
For every n-ary relationship type R where n>2, we make a new table S to represent R. We contain as foreign key attributes in s the primary keys of the relations that show the parti
SET concept is used in which type of modelling? SET concept is used in Network Model.
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