Database System Concepts
7th Edition
ISBN: 9780078022159
Author: Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Publisher: McGraw-Hill Education
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Expert Solution & Answer
Chapter 17, Problem 21E
Explanation of Solution
a.
Example of a schedule using pred_read operation:
The Phantom phenomenon occurs when two transactions do not access a common record and yet conflict.
Suppose the given additional operation pred_read(r, P) on relation r with predicate P.
Consider the example of a schedule which depicts the phantom phenomena:
| T1 | T2 |
| pred_read(t, P) | |
|
insert(r) write(B) commit | |
|
read(B) comm... |
Explanation of Solution
b.
Example of a schedule:
Consider the example of a schedule where one transaction makes use of the operation pred_read(r, P) and another transaction deletes a tuple from relation r, and still a phantom conflict is not exhibited:
| T1 | T2 |
| pred_read(t, t... |
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Microprocessor 8085 Lab Experiment
Experiment No. 3 Logical Instructions
Write programs with effects
1. B=(2Dh XOR D/2) - (E AND 2Eh+1) when E=53, D=1Dh
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