Page 31 - DCAP402_DCAO204_DATABASE MANAGEMENT SYSTEM_MANAGING DATABASE

Database Management Systems/Managing Database

Notes
Projection 1
Eid Dep-Name Sex Relationship
12354261 Nivedita F Mother
12354263 Lizzi F Sister
12354267 Raven F Doughtier

2. (DNo = 7 AND Address = ‘New Jersey’) OR (DNo = 8 AND Address = ‘Detroit’) EMPLOYEE

This condition selects the rows from employee which satisfy the conditions.
DNo = 7 and address = ‘New Jersey’ OR the condition
DNo = 8 and address ‘Detroit’.
If either of the conditions are satisfied then that row is selected.
The boolean operators used here convey the following meaning.

A AND B = TRUE if A, & B, are true i.e., the row must satisfy both conditions (A & B ) in
1 1 1 1
order to get selected.
(A B ) A OR B = TRUE if either A OR B is true.
1 1 1 1 1 1
(A B ) A AND B = False if either of A & B are false.
1 1 1 1 1 1
(A B ) A OR B = False if both of A, and B, are false.
1 1 1 1
The resulting relation is,
Projection 2

Age Ename Eid Bdata Address Sex ($) Salary Dno Phone No.
41 John 12345261 10-8-1965 New Jersey M 25000 7 773213218
51 Bill 12345265 12-5-1955 Detroit F 35000 8 773271142

Some examples of the select operator:
DEPARTMENT
manager-id = 4341
EMPLOYEE
(Salary > 40000 AND age < 40) OR (Salary 20000 AND age 20)
DEPENDENT. Different comparison operators can be
(Dep-Name = ‘Raven’) OR (relationship = ‘Brother’)
used with select operator.
(a) < Less than

(b) > Greater than
(c) = Equal to
(d) Not equal to
(e) Less than or equal to
(f) Greater than or equal to.

We can even use boolean operator “not” to negate a condition.
3. Display all the information of projects except those which are located in Chicago.
= PROJECT
Not Plocation ‘Chicago’

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