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!
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 such that R3 = {t | R1 ∋ t ∨ R2 ∋ t}.
Example
R1
X
Y
A1
B1
A7
B7
A2
B2
A4
B4
R2
A
B
A3
B3
R3 = R1 ∪ R2 is
Q
Note: 1) Union is a commutative operation, i.e, R ∪ S = S ∪ R.
2) Union is an associative operation, i.e.
R ∪ (S ∪ T) = (R ∪ S) ∪ T.
We define a view in SQL through using the create view command. To describe a view, we must provide the view a name and must state the query in which computers the view. The form of
What are the functions of an accumulator? The accumulator is the register associated with the ALU operations and sometimes I/O operations. It is an integral part of ALU. It hol
1.Why we need data mining? Give an example to illustrate your answer. 2. Why data mining is considered as "misleading name"? 3. Distinguish the difference between database an
Define the terms i) DDL ii) DML DDL: Data base schema is specified by a set of definitions expressed by a special language known as a data def
Construct an ER diagram for a hospital along with a set of patients and a set of medical doctors Associate with every patient a log of the several tests and examinations conducted.
What does Aggregation mean?
non numeric literals
What are the various properties of Relational tables? Relational tables have 6 properties: 1. Each row is unique. 2. Column values are of the same kind. 3. Values are
Define a table in SQL known as Client that is used to store information about the clients. Define CLIENT_NO as the primary key whose first letter must begin with ‘C'. Also ensure t
What are the authentication modes in SQL Server? How can it be changed? Windows mode and Mixed Mode - SQL and Windows. To alter authentication mode in SQL Server click Start, P
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