meljun cortes computer information processing chapter 10 with notes
TRANSCRIPT
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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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DATABASE MANAGEMENT SYSTEMS
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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DATABASE MANAGEMENT SYSTEMS
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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DATABASE MANAGEMENT SYSTEMS
Data Security
Ensure data is not misused
Authorized accessAccess privileges
Examples
Read-only Full-update
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DATABASE MANAGEMENT SYSTEMS
Backup and Recovery
Make backups (copies) on a regular basis
Log
Before image
Actual change
After image
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DATABASE MANAGEMENT SYSTEMS
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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DATABASE ADMINISTRATION
Role of the user
Become familiar with the data
Specify additions to the database
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DATABASE ADMINISTRATION
Database Design Guidelines
Determine the purpose of the database
Design the tables
Design the fields for each table
Determine the relationships among the tables