how data base is used in information system.. naeem

1. INFORMATION
SYSTEM
Lecture # 12

2. Principles of
Information Systems
(Eighth Edition)
CHAPTER 5 (CONTINUED)
ORGANIZING DATA AND
INFORMATION

3. DATA MODELING AND THE
RELATIONAL DATABASE MODEL
 When building a database, an organization must
consider:
Edition
Principles of Information Systems, Eighth
 Content: What data should be collected and at what
cost?
 Access: What data should be provided to which users
and when?
 Logical structure: How should data be arranged so
that it makes sense to a given user?
 Physical organization: Where should data be
physically located?
3

4. DATA MODELING
 Building a database requires two types of designs
 Logical design: abstract model of how the data
should be structured and arranged to meet an
Edition
Principles of Information Systems, Eighth
organization’s information needs
 Physical design: starts from the logical database
design and fine-tunes it for performance and cost
considerations
4

5. DATA MODELING (CONTINUED)
 Data model: diagram of data entities and their
relationships
Edition
Principles of Information Systems, Eighth
 Entity-relationship (ER) diagrams: data
models that use basic graphical symbols to show
the organization of and relationships between
data
5

6. DATA MODELING (CONTINUED)
Figure 5.4: An Entity-Relationship (ER) Diagram for a Customer Order
Database
Principles of Information Systems, Eighth Edition 6

7. THE RELATIONAL DATABASE
MODEL
 Relational model: describes data in which all
data elements are placed in two-dimensional
tables, called relations, that are the logical
Edition
Principles of Information Systems, Eighth
equivalent of files
 Each row of a table represents a data entity
 Columns of the table represent attributes
 Domain: allowable values for data attributes
7

8. THE RELATIONAL DATABASE
MODEL (CONTINUED)
Edition
Principles of Information Systems, Eighth
Figure 5.5: A Relational Database Model 8

9. THE RELATIONAL DATABASE
MODEL (CONTINUED)
 Selecting: eliminates rows according to certain
criteria
Edition
Principles of Information Systems, Eighth
 Projecting: eliminates columns in a table
 Joining: combines two or more tables
 Linking: manipulating two or more tables that
share at least one common data attribute to
provide useful information and reports
9

10. THE RELATIONAL DATABASE
MODEL (CONTINUED)
Edition
Principles of Information Systems, Eighth
Figure 5.6: A Simplified ER Diagram Showing the Relationship Between
the Manager, Department, and Project Tables 10

11. THE RELATIONAL DATABASE MODEL
(CONTINUED)
Edition
Principles of Information Systems, Eighth
11
Figure 5.7: Linking Data Tables to Answer an Inquiry

12. THE RELATIONAL DATABASE MODEL
(CONTINUED)
 Data cleanup: process of looking for and fixing
inconsistencies to ensure that data is accurate and
complete
 Eliminate redundancies and anomalies
Principles of Information Systems, Eighth Edition 12

13. THE RELATIONAL DATABASE MODEL
(CONTINUED)
Edition
Principles of Information Systems, Eighth
Table 5.3: Fitness Center Dues
13

14. THE RELATIONAL DATABASE MODEL
(CONTINUED)
Table 5.4: Fitness Center Members
Table 5.5: Dues Paid
Principles of Information Systems, Eighth Edition 14

15. DATABASE MANAGEMENT SYSTEMS
(DBMSS)
 Creating and implementing the right database
system ensures that the database will support both
Edition
Principles of Information Systems, Eighth
business activities and goals
 DBMS: a group of programs used as an interface
between a database and application programs or a
database and the user
15

16. OVERVIEW OF DATABASE TYPES
 Flat file
 Simple database program whose records have no
relationship to one another
Edition
Principles of Information Systems, Eighth
 Single user
 Onlyone person can use the database at a time
 Examples: Access, FileMaker, and InfoPath
 Multiple user
 Allowsdozens or hundreds of people to access the
same database system at the same time
 Examples: Oracle, Sybase, and IBM
16

17. PROVIDING A USER VIEW
 Schema: description of the entire database
 Typically used by large database systems to define
tables and other database features associated with a
Edition
Principles of Information Systems, Eighth
person or user
 A DBMS can reference a schema to find where to
access the requested data in relation to another
piece of data
17

18. CREATING AND MODIFYING THE
DATABASE
 Data definition language (DDL): collection of
instructions and commands used to define and
describe data and relationships in a specific
Edition
Principles of Information Systems, Eighth
database
 Allows the database’s creator to describe the data
and relationships that are to be contained in the
schema
 Data dictionary: detailed description of all the
data used in the database
18

19. CREATING AND MODIFYING THE
DATABASE (CONTINUED)
Figure 5.10: Using a Data Definition Language to Define a Schema
Principles of Information Systems, Eighth Edition 19

20. CREATING AND MODIFYING THE
DATABASE (CONTINUED)
Figure 5.11: A Typical Data Dictionary Entry
Principles of Information Systems, Eighth Edition 20

21. STORING AND RETRIEVING DATA
 When an application program requests data from
the DBMS, the application program follows a
logical access path
Edition
Principles of Information Systems, Eighth
 When the DBMS goes to a storage device to
retrieve the requested data, it follows a path to
the physical location (physical access path) where
the data is stored
21

22. STORING AND RETRIEVING DATA
(CONTINUED)
Figure 5.12: Logical and Physical Access Paths
Principles of Information Systems, Eighth Edition 22

23. MANIPULATING DATA AND
GENERATING REPORTS
 Data manipulation language (DML):
commands that manipulate the data in a
database
Edition
Principles of Information Systems, Eighth
 Structured Query Language (SQL)
 Adopted by the American National Standards
Institute (ANSI) as the standard query language for
relational databases
 Once a database has been set up and loaded with
data, it can produce reports, documents, and
other outputs
23

24. MANIPULATING DATA AND GENERATING
REPORTS (CONTINUED)
Table 5.6: Examples of SQL Commands
Principles of Information Systems, Eighth Edition 24