CPosthw1 Ecn 306 Fall2014ess(1)

8/11/2019 CPosthw1 Ecn 306 Fall2014ess(1)

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Chapter 1B

The Database Environment

& Development Process


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Database Advantages

2Database Systems, 10th Edition


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DBMS Functions

4

File Related:

Data dictionarymanagement

stores metadata, lookup relationships, automatic changes

Data storagemanagement

complex structures, performance tuning, physical files

Data accessmethods (transformation & presentation)

DBMS transforms physically retrieved data to conform tousers logical expectations

Multiple viewsof the data

Database Systems, 10th Edition

DBMS

Software to ProcessQueries/Programs

Software to AccessStored Data


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DBMS Functions (2)

Multiple-User related:

Security management

User security and data privacy - rules for access (Blackboard)

Multiuser access controlconcurrent operations

Backup and recovery management

Data integrity management

Enforces integrity rules; min redundancy, max consistency Database access languagesSQL

Database communication interfaces

Multiple networks, forms input, website reports, email distribution


DBMS

Software to ProcessQueries/Programs

Software to AccessStored Data


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Database Types

Database Systems, 10th Edition6


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Two Approaches to Database

and IS Development System Development Life Cycle (SDLC)

Detailed, well-planned development process

Time-consuming, but comprehensive

Long development cycle

Prototyping

Rapid application development (RAD)

Cursory attempt at conceptual data modeling

Define database during development of initial prototype

Repeat implementation and maintenance activities withnew prototype versions



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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

SDLC


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Prototyping


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Evolution of DB Technologies

Parent

Child

ParentParent

ChildParent


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The Relational Model Developed by E.F. Codd (IBM) in 1970 Tables (relations)

Matrix consisting of row/column intersections

Each column in a relation is called an attribute

Each row in a relation is called a tuple

Allowable values for attributes - Domain

Relational models were considered impractical in 1970

Model was conceptually simple at expense of computer

overhead



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The Entity Relationship Model Widely accepted standard for data

modeling

Introduced by Chen in 1976

Graphical representation of entities and

their relationships in a database structure

Entity relationship diagram (ERD)

Uses graphic representations to modeldatabase components

Entity is mapped to a relational table



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Importance of Database Design


1. List the issues caused by this design.

2. Create a new design that addresses the issues identified.

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CPosthw1 Ecn 306 Fall2014ess(1)