Chapter 6: Database and Information Management
6.1 - Organizing Data in Traditional File Environment
Problems with the Traditional File Environment
- data redundancy
- data inconsistency,
- program-data dependence: the coupling of data stored in files and the specfic programs
required to update and maintain those files so that changes in programs require changes to the
- lack of flexibility
- poor security
- lack of data sharing and availability
6.2- The Database Approach to Management
database management system (DBMS): software that permiits an organization to centralize
data, manage them efficiently, and provide access to the stored data by application programs
- DBMS relieves the programmer or end user from the task of understanding where and how the
data are actually stored by separating the LOGICAL and PHYSICAL views of the data.
LOGICAL: presents data as they would be perceived by end users or business specialists
PHYSICAL: shows how the data are actually organized and structured on physical storage
How a DBMS Solves the Problems of the Traditional File Environment
- enables the organization to centrally manage their data
relational DBMS: A type of logical database model that treats data as if they were stored in 2-D
tables (aka relations or tuples). It can relate data stored in one table to data stored in another as
long as the 2 tables share a common data element.
fields = columns
tuples: A row or record in a relational database
key field: A field in a record that uniquely identifies instances of that record so that it can be
retrieved, updated or sorted.
primary key: Unique identifier for all the info in any row of a database table
foreign key: Field in a database that enables users to find related info in another database
Operations of a Relational DBMS - in a relational database, 3 basic operations are used to develop useful sets of data
1. SELECT : creates a subset consisting of all records in the file that meet stated criteria.
2. JOIN: combines relational tables to provide user with more info than is available in individual
3. PROJECT: creates a subset consisting of columns in a table, permitting the user to create
new tables that contain only the information required.
object-oriented DBMS: store the data and procedures that act on those data as objects hat
can be automatically retrieved and shared.
- they are becoming more popular because they can be used to manage the various multimedia
components or Java applets used in Web applications, which typically integrate pieces of info
from a variety of sources.
- although OODMSs can store more complex types of info than relational DBMSs, they are
relatively slower for processing large numbers of transactions
object-relational DBMSs : Hybrid of OODMSs and DMSs , with the capabilities of both.
Capabilities of Database Managemen Systems
data definition: capability to specify the structure of the content of the database. it is used to
create database tables and to define the characteristics of the fields in each table.
data dictionary: an automated or manual file that stores definitions of data elements and their
Querying & Reporting
data manipulation: A language associate with a database management system that end users
and programmers use to manipulate data in the database.
- microsoft access has a rudimentary data dictionary that displays information about the size,
format, and other characteristics about each field in a database.
Structured Query Language:The standard data manipulation language for relational database
- the database requires both conceptual design and physical design
- the conceptual/logical design of a a database is an abstract model of the database from a
business perspective while the physical design shows how the database is actually arranged on
direct-access storage devices.
Normalization and Entity-Relationship Diagrams normalization: The process of creating small, stable, yet flexible and adaptive data structures
from complex groups.
- An unnormalized relation contains repeating groups.
repeating data groups: Unnormalized data wherein there can be multiple records associated
with high-impact loads or thousands of repetitions with low-impact loads.
referential integrity: Rules to ensure that relationships between linked database tables
entity-relationship diagrams: A methodology for documenting databases illustrating the
relationship between various entities in the database.
distributed database: one that is stored in more than one physical location.
- reduce the vulnerability of a single massive site.
6.3 - Using Databases to Improve Business Performance ad Decision Making
data warehouse: a database that stores current and historical data of potential interest to
decision maker throughout the company.
- the data warehouse makes the data available for anyone to access as needed, but it can’t be
- the data warehouse extracts current and historical data from multiple operational systems