meljun cortes computer information processing chapter 10 with notes

7/31/2019 MELJUN CORTES Computer Information Processing Chapter 10 With Notes

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CCT101: Chapter 10

Databases


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OBJECTIVES

Explain why data and information are important to an

organization

Differentiate between file processing and databases

Discuss the advantages of using a databasemanagement system (DBMS)

Describe characteristics of relational and object-oriented

databases

Discuss the responsibilities of the data and databaseadministrators


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DATA AND INFORMATION

Data

Collection of items such as words, numbers, images,

and sounds that are not organized and have littlemeaning individually

Information

Data that is organized and meaningful For example, Grade report


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DATA AND INFORMATION

Data Integrity

Reliable data entry

GIGO

Data security

Ensure data is not misused or lost

Backup


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DATABASE MANAGEMENT SYSTEMS

Software or a set of programs designed to

control access to the database and manage data

resources efficiently

Available for various sizes and types of

computers


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Data Dictionary

Stores data about each file in the database

and each field within those files

Perform validation checks

Default values


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Data Maintenance and Retrieval

Query

To retrieve data from a database

Various methods of accessing data

Query language

Query-by-example (QBE)

Form/ Data entry form

Report generator/ Report writer


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Data Security

Ensure data is not misused

Authorized accessAccess privileges

Examples

Read-only Full-update


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Backup and Recovery

Make backups (copies) on a regular basis

Log

Before image

Actual change

After image


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Recovery utilities

Rollback/ Backward recovery

The log is used to reverse any changes made

Roll-forward/ Forward recovery

The log is used to re-enter changes automatically since the

last save or backup

Some database recovery utilities use acombination of both techniques


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Types of Data Model

Hierarchical

Network

Relational

Object oriented

Object relational


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RELATIONAL DATABASES

Relation or table

Tuple or row

Attribute or column

Relationships

Relational algebra

Uses variable and operations to build a new relation

Projection

Selection

Join


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RELATIONAL DATABASES

Structured Query Language (SQL)

Keywords and rules used to implement

relational algebra operations


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OBJECT-ORIENTED DATABASES

Object contain both data and the activities to

read or manipulate data

Advantages

Can store more types of data

Faster way to access data

Object query language

Used to develop object-oriented and object-relational

databases


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DATABASE ADMINISTRATION

Role of the Data and Database

Administrators

Designing databases

Creating and maintaining data dictionary

Monitoring security and performance

Implementing and testing backup andrecovery procedures


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Role of the user

Become familiar with the data

Specify additions to the database


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Database Design Guidelines

Determine the purpose of the database

Design the tables

Design the fields for each table

Determine the relationships among the tables

meljun cortes computer information processing chapter 10 with notes

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