Reviewer - Information Management

What is a database?

Collection of data organized so you can access, retrieve, and use it

Database Management System (DBMS)

Software system that allows you to define, construct, and manipulate databases used for storing customer and financial information of an organization

Flat File Databases

Simple text files that store data in a single table.

Relational Databases

Complex databases that store information in multiple tables.

Factors to consider in database design

Efficiency, Integrity, Privacy, Security, Flexibility.

Data Model

Determines the structure of data and sequence of storing, organizing, and manipulating the data in a database system.

Types of Data Model

Hierarchical model, Network model, Relational model, Object-oriented model, and Object-relational model.

Hierarchical model

Uses two types of data structures, records, and parent-child relationships to define the data and relationships among data.

Network model

Database model used to represent objects and relationships among them.

Relational model (1970, E. F. Codd)

Provides a simple, rigorously defined concept of how data is perceived by users.

Domain

Set of defined atomic values for an attribute

Attribute

Name of a role played by a domain in the relation.

Tuple

Each row in a relation, a set of related data values.

Data

Raw facts.

Information

Data that is organized and meaningful.

Data Integrity

Degree to which data is correct.

Garbage in, garbage out (GIGO)

Means you cannot create correct information from incorrect data.

Qualities of Valuable Information

Accurate, Verifiable, Timely, Organized, Accessible, Useful.

Hierarchy:

Database contains files, files contain records, records contain fields, and fields contain characters.

Field:

Combination of one or more characters. Smallest unit of data a user accesses.

Field size

Maximum number of characters a field can contain.

Field name

Uniquely identifies each field.

Data type

Specifies the kind of data a field contains.

Common Data Types:

Text, Numeric, AutoNumber, Currency, Date, Memo, Yes/No, Hyperlink, Object.

Record:

Group of related fields.

Key field or primary key

uniquely identifies each record.

Data File:

Collection of related records stored on disk.

File Maintenance:

Procedures to keep data current, e.g., adding, changing, or deleting records.

Validation:

Process of comparing data with a set of rules to check correctness. Reduces data entry errors and enhances data integrity.

Types of Validity Checks:

Check Digit, Alphabetic/Numeric Check, Completeness Check, Range Check, Consistency Check.

File Processing System

Each department/area within an organization has its own set of files. Records in one file may not relate to records in another file.

Database Approach:

Programs and users share data in a database, Secures data so only authorized users access certain data.

Strengths of Database Approach

Reduced data redundancy, Improved data integrity, Shared data, Easier access, Reduced development time.

Advantages of DBMS

Data Integrity, Data Security, Data Independence, Concurrent Access and Transactions, Data Redundancy Reduction, Data Query and Retrieval.

Disadvantages of DBMS

Complexity and Cost, Size and Resource Requirements, Risk of System Failure, Security Concerns.

Data Dictionary

Contains data about each file in the database and each field within those files. Request for specific data from a database

Form

Window on screen for entering or changing data in a database

Report Generator

Allows users to design a report on-screen, retrieve data into the report design, and display or print reports

Data Security

DBMS ensures only authorized users can access data

Read-only privileges

Users can view data but cannot change it.

Full-update privileges

Users can view and change data.

Backup

A copy of the entire database.

Log

A listing of activities that change database contents

Recovery Utility

Uses logs and/or backups to restore databases when damaged or destroyed.

Rollforward

DBMS uses log to re-enter changes made to the database since the last save or backup

Rollback

DBMS uses log to undo changes made to the database during a certain period of time

Data Model

Rules and standards that define how the database organizes data, Defines how users view the organization of data.

Relational Database

Stores data in tables consisting of rows and column, Each row has a primary key

Structured Query Language (SQL)

Allows management, update, and retrieval of data

Steps in Planning a Database

Determine the purpose of your database, Determine the fields needed, Determine the tables needed, Identify fields with unique values for each record, Determine relationships between tables, Filter the design, Re-examine what fields will go into your database, Enter data and create other database objects.

Database Analyst (DA)

Focuses on meaning and usage of data

Database Administrator (DBA)

Creates and maintains data dictionary, manages database security, monitors database performance, and checks backup/recovery procedures.

DBMS

Database Management System.

SQL

Structured Query Language.

DBA

Database Administrator.

GIGO

Garbage In, Garbage Out.

DA

Database Analyst.

Database

Collection of data organized so you can access, retrieve, and use it.

Data Warehouse

Huge database system that stores and manages data required to analyze historical and current transactions.

Data Dictionary

Contains data about each file in the database and each field within those files.

Field

Combination of one or more characters and the smallest unit of data the user accesses.

Data Integrity

Degree to which data is correct.

Information

Data that is organized and meaningful.

Rollback

DBMS uses a log to undo changes made to the database during a certain period.

File Maintenance

Procedures that keep data current.

Validation

Process of comparing data with a set of rules to check if data is correct.

Log

Listing of activities that change database contents.

Backup

A copy of the entire database.

Range Check

Determines whether a number is within a specified range.

Form

Window on screen for entering or changing data in a database.

Report Generator

Allows users to design a report on-screen, retrieve data into the report design, then display or print reports.

Data File

Collection of related records stored on disk.