Title: Instructor's Perspective - Module 9
Course: CIS2321 Information Systems > Section: Module 9 - Data Design

Module 9: Data Design

In this module we cover files and tables that contain data about things that affect
the information system.

The overall data structure of a database consists of linked tables. A database
management system (DBMS) is a collection of tools used to manage the data in
a database. DBMSs are better than traditional file-oriented systems. It offers
scalability, support for organization-wide access, data sharing, balancing user
requirements, enforcement of standards, controls redundancy, security, flexibility,
and data independence.

Components of a DBMS include interfaces, a data manipulation language,
schemas, and a physical data repository. Additional data management
techniques include data warehousing and data mining. Data mining also includes
data about how users interact with a site, and market basket analysis, which can
identify product relationships and consumer patterns.

An entity in the system is anything for which data is collected and maintained. A
field, or attribute, is a single characteristic of an entity. A record, also referred to
as a tuple, is a set of related fields that describes one entity. Records are
grouped into files and tables.

A graphic representation of all system entities and the relationships among them
is called an entity-relationship diagram (ERD). It is based on entities and data
stores prepared during the systems analysis phase. There are three basic
relationships represented in an ERD; one-to-one (1:1), one-to-many (1:M), and
many-to-many (M:N).

To avoid problems in data design you should use normalization. A first normal
form (1NF) record has no repeating groups, second normal form (2NF) is if it is in
1NF and all non-key fields depend on the primary key, third normal form (3NF) is
if it is in 2NF and if no field depends on a non-key field.

Logical storage is information on how a person sees the data, regardless of how
or where that information actually is ordered or stored. Physical storage is the
actual location in the computer system where the data is stored. You must
implement file and database control measures to ensure the integrity of your
data.

Attachments

- Mod9_InstructorPerspective.pdf