IS 340
Management
Information Systems
(NOTE:
the text instructs the reader to go to chapter 3 for foundational
database concepts; the presentation in these notes is the content and order
from the 3rd edition of the text, but includes all the information
from the 5th edition)
Database Design – the correct Data
Model (there are several types) is critical in creating an effective and
efficient organizational database
I.
Database
Management for Strategic Advantage – data must be Collected, Processed (into
information), and Distributed, but it must also be Stored and Retrieved. In order to do this efficiently, we use
Databases.
Database – a collection of related data organized to facilitate data searches
A. The Database Approach:
Foundation Concepts
Database Management System (DBMS) – software application that enables
creation, organization, storage, and distribution of data from one or several
databases
Entity – anything about which you collect data
Attribute – a description of an entity
Record – a collection of related attributes that describe a single entity
Table – a 2-dimensional representation of similar data, consists of Columns
(Field or Attribute) and Rows (Record or Tuple)
B.
Advantages of the Database Approach – instead of keeping each piece of
data multiple times in various locations, a database keeps each piece of data
ONCE (not strictly true, but that is the basic idea)
Not In Text: Advantages of the Database Approach:
1. Control Redundancy
2. Eliminate Inconsistency
3. Promote Data/Program Independence
C. Effective Management of Databases – a
database is a complicated, expensive software application that requires workers
with special training to administer and manage it; these persons are highly
trained, expensive to hire, and require ongoing training (expensive)
Database Administrator (DBA) –
responsible for development and management of the firm’s databases; the DBA
implements business decisions made by organizational managers
II.
Key Database Activities
A. Entering and Querying Data – some DBMS
software allows user to create and manage their own database applications
Form – used for
data input
Report – used for
data output
Query – a
question asked of the database
Structured Query Language (SQL) – the most
popular language for interfacing with the database
Query by Example (QBE) – a simple
method of interfacing with the database
B. Creating Database Reports – Report Generators
C. Database Design – a database must be carefully
designed to work effectively and efficiently for a particular set of situations
(for a specific organization)
Data Model – a map or
diagram representing the entities and their relationships in a given set of
circumstances; Entity Relationship Diagram (ERD) is the most popular data model
today
Primary Key –
attribute with a UNIQUE value that specifically identifies a particular
entity instance
Combination (Concatenated) Key – several
attributes joined together to create a primary key
Secondary Key – although
not the primary key, an attribute used to identify records that share a common
value
Foreign Key – a
primary key from one record that is used as a non-key attribute in another
record
D. Associations – relationships between
entities, may be One-To-One (a baseball team has one home stadium, and a
stadium has one home team), One-To-Many (a baseball team has many
players, but a player is on only one team), or Many-To-Many (a baseball
player is in many games, and each game has many players)
E. Entity-Relationship Diagramming – a modeling
technique that presents the Data as a series of entities and shows the
relationships (a line with a description) between the entities (rectangles with
the entity name); ERD is the most popular data model today
F. The Relational Model – a method of showing a
database as a series of 2-dimensional tables (Relations) of Columns
(Attributes/Fields) and Rows (Tuples/Records); the most popular database model
today; very powerful and intuitive
A good Relational Design eliminates
unnecessary duplication and is easy to maintain
G. Normalization – a method of arranging data
attributes in data relations (tables) to make complex databases more efficient
and more easily handled
H. Data Dictionary – holds information about the
database; helps enforce business rules; holds Metadata
Metadata – data
about the data (data types, sizes, names, etc.)
III. How Organizations Get the Most from Their
Data – watch out for too much data! An
enormous amount of data is available – how do you get just what you need
without being deluged by too much unneeded data? A database should help with this.
A. Linking Web Site Applications to
Organizational Databases – many firms are linking their databases to their
websites to provide real-time access to necessary information