Computer

Introduction

 

Definition: A computerized record keeping system A user would want to be able to do (at least):

– – – – – – Adding a new empty table (or file for the time being) Inserting new data Retrieving data Updating data Deleting data Removing tables

1/16/2012

CSC4341

1

An Example of A Relation (a table)

BIN# 2 3 6 12 21 22 30 43 45 48 50 51 52 58 64 72 WINE Chardonnay Chardonnay Chardonnay Joh Riesling Fume Blanc Fume Blanc Gewurztraminer Cab Sauvignon Cab Sauvignon Cab Sauvignon Pinot Noir Pinot Noir Pinot Noir Merlot Zinfandel Zinfandel PRODUCER Buena Vista Geyeser Peak Simi Jekel Ch St. Jean Robt Mondavi Ch St. Jean Windsor Geyeser Peak Robt Mondavi Gary Farrell Fetzer Dehlinger Clos du Bois Cline Rafanelli YEAR 1997 1997 1996 1998 1997 1996 1998 1991 1994 1993 1996 1993 1996 1994 1994 1995 BOTTLES 1 5 4 1 4 2 3 12 12 12 3 3 2 9 9 2 READY 1999 1999 1998 1999 1999 1998 1998 2000 2002 2004 1999 2000 1998 2000 2003 2003

1/16/2012

CSC4341

2

SELECT BIN#, WINE, PRODUCER FROM CELLAR WHERE READY = 2000;

BIN# WINE 43 Cab Sauvignon 51 Pinot Noir 58 Merlot PRODUCER Windsor Fetzer Clos du Bois

INSERT INTO CELLAR (BIN#, WINE, PRODUCER, YEAR, BOTTLES, READY) VALUES (53, ‘Pinot Noir’, ‘Saintsbury’, 1997, 6, 2001); UPDATE CELLAR SET BOTTLES = 4 WHERE BIN# = 3; DELETE FROM CELLAR WHERE BIN# = 2;

1/16/2012 CSC4341 3

What Is A Database System?

• A computerized system whose overall purpose is to maintain information and to make it available on demand • Four components: Data, Hardware, Software, Users DBMS

Database

Application programs

1/16/2012 CSC4341

End users

4

Database Systems (continued)



Data

– Integrated A unification of several distinct files or tables – Shared Individual data shared among different users



Hardware

– Secondary storage – Hardware processors



Software

– A layer between physical database itself and users – a. k. a. Database Management Systems (DBMS) – Support user...