Chapter 7 - Storing Organizational Information
What is information?
KEYS AND RELATIONSHIP
Information is everywhere in an organization
Information is stored in databases
Database –
maintains information about various types of objects (inventory), events
(transactions), people (employees), and places (warehouses)
Database models include:
Hierarchical database model – information is organized into a tree-like structure (using
parent/child relationships) in such a way that it cannot have too many
relationships – organizational chart
Network database model – a flexible way of representing objects and their relationships
Relational database model – stores information in the form of logically related
two-dimensional tables
ENTITY AND ATTRIBUTE
Entity – a person, place, thing, transaction, or
event about which information is stored
The rows in each table contain
the entities
Attributes
(fields, columns) – characteristics or
properties of an entity class
The columns in each table
contain the attributes
Primary keys and foreign keys identify the
various entity classes (tables) in the database
Primary key –
a field (or group of fields) that uniquely identifies a given entity in a table
Foreign key –
a primary key of one table that appears an attribute in another table and acts
to provide a logical relationship among the two tables
DATABASE ADVANTAGE
Database advantages from a business
perspective include
-Increased flexibility : A well-designed database should:
Handle changes quickly and
easily
Provide users with different
views
Have only one physical view
•Physical view – deals with the physical
storage of information on a storage device
Have multiple logical views
•Logical view – focuses on how users logically
access information
-Increased scalability and
performance : A database must scale to meet increased
demand, while maintaining acceptable
performance levels
Scalability –
refers to how well a system can adapt to increased demands
Performance –
measures how quickly a system performs a certain process or transaction
-Reduced information redundancy : Databases reduce information redundancy
Redundancy –
the duplication of information or storing the same information in multiple
places
Inconsistency is one of the primary problems
with redundant information
-Increased information integrity
(quality) : Information integrity means measures the quality of information
Integrity constraint –
rules that help ensure the quality of information
1.Relational integrity constraint - is used to ensure accuracy and
consistency of data in a relational database.
•Users cannot create an order
for a nonexistent customer.
•An order cannot be shipped
without an address.
2.Business-critical integrity
constraint –
•In database management, business-critical integrity constraints enforce a company's rules.
•For example, a company can code a constraint that prevents a checkout
counter from giving a customer a discount greater than 25 percent or refuses
returns of produce purchased more than 15 days ago.
-Increased information security : Information is an organizational asset and
must be protected
Databases offer several security features
including:
Password – provides authentication of
the user
Access level – determines who has access to the different types of
information
Access control – determines types of user access, such as read-only access
DATABASE MANAGEMENT SYSTEM
Database
management systems (DBMS) – A computer software
through which users and application programs interact with a database
DATA DRIVEN WEBSITE
Data-driven
Web sites – an interactive Web site kept constantly
updated and relevant to the needs of its customers through the use of a
database. A data-driven Web site invites visitors to select and view what they
are interested in by inserting a query, which the Web site then analyzes and
custom builds a Web page in real-time that satisfies the query.
The advantages :
-Development
-Content Management
-Future Expandability
-Minimizing Human Error
-Cutting Production and Update Costs
-More Efficient
-Improved Stability
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