OCA Oracle 10G Administration-I
Chapter 8 Managing Consistency and Concurrency
Objectives
Undo Management
Monitor and administer undo. Configure undo retention. Guarantee undo retention. Use the Undo Advisor. Describe the relationship between undo and t
Predicates
1
Specification Problem
Consider the following fragment of a specification
written in natural language:
All files that are larger than 1,000 blocks are to be moved
to tape provided that they have not been referenced
within the last 100 days a
Propositions
1
University of Virginia
Specification Problem
Consider the following fragment of a
specification written in natural language:
There are two types of command that can be entered
into the computer system.
The command types are the USER comm
Integers and Division
IntegersandDivision:Whats
Important
Divides: a | b
Mod: a mod m; a b (mod m)
GCD(a,b): greatest common divisor
LCM(a,b): least common multiple
(Prime) Factors Unique for a given integer & each
integers prime factors are unique
Floor
Proofs
1
Logic
If "experts" could always be trusted to make the right moral decision,
then public participation would not be necessarybut they cannot be,
and so it is.
Source: Keay Davidson, Carl Sagan: A Life, John Wiley & Sons, 1999, p. xv.
- http:/www.
Functions!
1
A Bit Of Terminology
Relation R on sets A and B: R (A B)
Not all elements of A or B need be in R
So there are four sets that we need to be concerned
about:
A
Source set
B
Target set
The part of A actually used in R Domain
The part of B a
Modulo Equivalences and RSA
Encryption
Definition of Modular Congruence
We say that is congruent to mod , if and only
if is divisible by .
That is .
Modular Equivalences
Let a, b, and n be any integers and suppose n>1. The following statements
are all e
Relations
Specification Fragment
Software is required to maintain a database of telephone numbers
within an organization.
Users will be known by last name and can have more than one
telephone number.
Four digit telephone number extensions must be stored.
Sets
1
University of Virginia
Specification Problem
Consider the following fragments of specification
written in natural language:
Software is required to maintain details of the users of a
computer system. Users will be people who are
permitted to use