Oracle SQL and PL/SQL Quick Reference
UPPER() lower() InitCap() LENGTH() ROUND(num, 2) TRUNC(num,2)
SUBS/TR(string, initial (pos: from left, neg: from right), length (optional))
INSTR(string, lookup (case sensitive), starting pos, nth occurrence (optional))
LPAD(string, total length, fill), RPAD(string, total length, fill character)
REPLACE(‘original’, ‘find’, ‘replace’), TRIM(whattotrim FROM string)
MOD(number, divisor) -> return remainder
MONTHS_BETWEEN(date, date), ADD_MONTHS(date, # of months to add)
NEXT_DAY(date, ‘FRIDAY’)
Read MoreUnderstanding PC Components and Startup Processes
Understanding PC Components and Startup
What is the BIOS?
The BIOS (Basic Input/Output System) is what allows the computer to start. It controls the keyboard and floppy disk, and allows control to be passed to the operating system.
What is the CMOS?
The CMOS (Complementary Metal-Oxide-Semiconductor) is a small RAM chip that stores the system’s configuration.
What is Setup?
Setup is a crucial program recorded in the BIOS chip. It’s used to change the modes of transmission and the recognition (or non-recognition)
Read MoreUnderstanding Computer Capabilities: Diligence, Versatility, and Memory
Understanding Computer Capabilities
Diligence
Unlike humans, computers never tire of repetitive tasks. They can continually work for hours without creating errors. Even when a large number of executions are needed, each execution requires the same duration and is executed with the same accuracy.
Versatility
Versatility is the quality of being flexible. Today, computers are used in various fields of our daily lives. For example, they are used as personal computers (PCs) for home use, for business-oriented
Read MoreOracle Products and Database Architecture Explained
Oracle Products
Oracle Databases
The Oracle database is designed for Enterprise Grid Computing.
Oracle Application Server
Certified for Java 2 Platform Enterprise Edition (J2EE), Oracle provides the tools to develop and deploy Web-based applications.
Oracle Applications
Oracle E-Business Suite is a complete set of business applications.
Oracle Collaboration Suite
Oracle Collaboration Suite is a single integrated system for all data communications.
Global Grid Forum (GGF)
The Global Grid Forum (GGF) is an
Read MoreDatabase Transaction Concurrency: Failures, Logs, and Schedules
Homework #9
Lauri Burke
CINS 370
4/29/2016
21.1. Concurrent Execution in Multiuser Systems
A multiuser system is a system which can be used by more than one user at a time.
Why is Concurrency Control Needed?
Concurrency control is used to prohibit transaction conflicts. Here are some examples of problems that can occur without it:
- The Lost Update Problem: Two or more transactions try to read and update the same data concurrently. The last update overwrites previous updates, resulting in lost data.
- Temporary
NP-Complete Problems and Reductions: A Detailed Look
NP-Completeness: Key Concepts
NP (Non-deterministic Polynomial time): Problems where a proposed solution (certificate) can be verified in polynomial time. A ‘guesser’ proposes a solution, and a ‘verifier’ checks it. Both guessing and verifying happen in polynomial time.
Every problem in NP can be reduced to SAT (Satisfiability) – Cook-Levin Theorem.
Problem Definitions
Independent Set (IS)
Given a graph G = (V, E) and an integer K, is there a set I (subset of V) with |I| ≥ K such that for any u, v
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