presentation on MIS

1. Lecture 3: Organizing Data
&
Information

2. Data
Data
A necessity for almost any enterprise to carry out its business. Consists of raw
facts, and when organized may be transformed into information
Database
A collection of data organized to meet users’ needs
Database management system (DBMS)
A group of programs that manipulate the database and provide an interface
between the database and the user of the database or other application programs

3. Hierarchy of Data
Hierarchy of data Example
Database
Files
Records
Fields
Characters
(bytes)
Personel file
Department file
Payroll file
(Project database)
005-10-6321 Johns Francine 10-7-65
549-77-1001 Buckley Bill 2-17-79
098-40-1370 Fiske Steven 1-5-85
(Personnel file)
098-40-1370 Feleke Steven 1-5-85 598 (Record containing SSN,
last name, first name, date
of hire)
FELEKE (Last name field)
1000100 (Letter ‘F’ in ASCII)

4. Terminology
Database
A collection of integrated and related files
File
A collection of related records
Record
A collection of related fields
Field
A group of characters
Character
Basic building block of information, represented by a byte

5. Data Entities, Attributes, and Keys
Entity
 A generalized class of people, places, or things (objects) for which data are
collected, stored, and maintained
E.g., Customer, Employee
Attribute
A characteristic of an entity; something the entity is identified by
E.g., Customer name, Employee name
Keys
A field or set of fields in a record that is used to identify the record
E.g, A field or set of fields that uniquely identifies the record

6. Keys and Attributes
Key field Attributes (fields)
Entities
(records)
Employee # Last name First name Hire date Dept. #
005-10-6321 Johns Francine 10-7-65 257
549-77-1001 Buckley Bill 2-17-79 650
098-40-1370 Fiske Steven 1-5-85 598

7. The Traditional Approach
The traditional approach…
Separate files are created and stored for each application program
Schematic

8. Application programs
Payroll
Payroll
programs
Reports
Data Files Users
Invoicing
Invoicing
programs
Reports
Inventory
control
Inventory
control
programs
Reports
Management
inquiries
Management
inquiries
programs
Reports
The Traditional Approach

9. Drawbacks
Data redundancy
Duplication of data in separate files
Lack of data integrity
The degree to which the data in any one file is accurate
Program-data dependence
A situation in which program and data organized for one application
are incompatible with programs and data organized differently for
another application

10. Database Approach
The database approach…
A pool of related data is shared by multiple application programs
Rather than having separate data files, each application uses a
collection of data that is either joined or related in the database
Schematic

11. Payroll data
Inventory
data
Invoicing
Data
Other
data
Database
management
system
Payroll
program
Inventory
program
Invoicing
program
Other
programs
Reports
Reports
Reports
Reports
Database Interface Applications programs Users
Database Approach

12. Advantages
 Improved strategic use of corporate data
 Reduced data redundancy
 Improved data integrity
 Easier modification and updating
 Data and program independence
 Better access to data and information
 Standardization of data access
 A framework for program development
 Better overall protection of the data
 Shared data and information resources

13. Disadvantages
Relatively high cost of purchasing and operating a DBMS in a
mainframe operating environment
 Increased cost of specialized staff
 Increased vulnerability

14. Data Modeling and Database Models (1)
Planned data redundancy
A way of organizing data in which the logical database design is
altered so that certain data entities are combined
Summary totals are carried in the data records rather than calculated
from elemental data
Some data attributes are repeated in more than one data entity to
improve database performance

15. Data Modeling and Database Models (2)
Data model
A map or diagram of entities and their relationships
Enterprise data modeling
Data modeling done at the level of the entire organization
Entity-relationship (ER) diagrams
A data model that uses basic graphical symbols to show the organization of and
relationships between data

16. Example:
Entity Relationship (ER) Diagram for a Customer
Ordering Database
Schematic

17. Order
Customer Product
1:N one-to-many
relationship
Last name Colour
Identification
number
Name
First
name
Identification
number
Attributes
Entities
1 N

18. Hierarchical Database Model
Hierarchical database model
A data model in which data are organized in a top-down, or inverted tree structure
Department
C
Employee
1
Employee
2
Employee
3
Employee
4
Employee
5
Employee
6
Department
B
Projects
Department
A

19. Network Data Model
Network data model
An expansion of the hierarchical database model with an owner-member
relationship in which a member may have many owners
Project
1
Project
2
Department
A
Department
B
Department
C

20. Relational Data Model
Relational data model
All data elements are placed in two-dimensional tables, called
relations, that are the logical equivalent of files
Schematic

21. Project Number Description Dept. Number
155 Payroll 257
498 Widgets 632
226 Sales manager 598
Dept. Number Dept. Name Manager SSN
257 Accounting 421-55-99993
632 Manufacturing 765-00-3192
598 Marketing 098-40-1370
SSN Last Name First Name Hire Date Dept. Number
005-10-6321 Johns Francine 10-7-65 257
549-77-1001 Buckley Bill 2-17-79 650
098-40-1370 Fiske Steven 1-5-85 598
Data Table 1: Project Table Data Table 2: Department Table
Data Table 3: Manager Table
Relational Data Model

22. Relational Database Terminology
Selecting
Data manipulation that eliminates rows according to certain criteria
Projecting
Data manipulation that eliminates columns in a table
Joining
Data manipulation that combines two or more tables
Linked
Relating tables in a relational database together

23. Linking Data Tables to Answer an Inquiry
Project Number Description Dept. Number
155 Payroll 257
498 Widgets 632
226 Sales manager 598
Dept. Number Dept. Name Manager SSN
257 Accounting 421-55-99993
632 Manufacturing 765-00-3192
598 Marketing 098-40-1370
SSN Last Name First Name Hire Date Dept. Number
005-10-6321 Johns Francine 10-7-65 257
549-77-1001 Buckley Bill 2-17-79 650
098-40-1370 Fiske Steven 1-5-85 598

24. Building and Modifying a Relational Database
Using Microsoft Access

25. Schemas and Subschemas
Schema
A description of the entire database
Subschema
A file that contains a description of a subset of the database and
identifies which users can perform modifications on the data items in
that subset
Schematic

26. DBMS
Schema
Subschema
B
Subschema
A
Subschema
C
User
1
User
2
User
3
User
4
User
5
Schemas and Subschemas

27. Data Definition Language
Data Definition Language (DDL)
A collection of instructions and commands used to define and describe data and data relationships in
a specific database
statements are used to define the database structure or schema. Some examples:
CREATE - to create objects in the database
ALTER - alters the structure of the database
DROP - delete objects from the database
TRUNCATE - remove all records from a table, including all spaces allocated for the records are
removed
COMMENT - add comments to the data dictionary
RENAME - rename an object

28. Data Manipulation Language (DML)
Data Manipulation Language (DML) statements are used for managing data within
schema objects. Some examples:
SELECT - retrieve data from the a database
INSERT - insert data into a table
UPDATE - updates existing data within a table
DELETE - deletes all records from a table, the space for the records remain
MERGE - UPSERT operation (insert or update)
CALL - call a PL/SQL
LOCK TABLE - control concurrency

29. Transaction and data control language
Data Control Language (DCL) statements used to control the data modifications. Some
examples:
GRANT - gives user's access privileges to database
REVOKE - withdraw access privileges given with the GRANT command
Transaction Control (TCL) statements are used to manage the changes made by DML
statements. It allows statements to be grouped together into logical transactions.
COMMIT - save work done
SAVEPOINT - identify a point in a transaction to which you can later roll back
ROLLBACK - restore database to original since the last COMMIT
SET TRANSACTION - Change transaction options like isolation level and what
rollback segment to use

30. Data Dictionary Features
Provide a standard definition of terms and data elements
Assist programmers in designing and writing programs
Simplify database modification
Reduce data redundancy
Increase data reliability
Faster program development
Easier modification of data and information

31. Logical and Physical Access Paths
Logical access path (LAP)
Application requires information from the DBMS
Physical access path (PAP)
DBMS accesses a storage device to retrieve data
Schematic

32. Data on
storage
devices
DBMS
Management
inquiries
Other
software
Application
programs
Physical access path (PAP)
Logical access path (LAP)

33. Manipulating Data
Concurrency control
A method of dealing with a situation in which two or more people need
to access the same record in a database at the same time
Data manipulation language (DML)
The commands that are used to manipulate the data in a database
Structured query language (SQL)
A standardized data manipulation language

34. Structured Query Language (SQL)
“Invented” at IBM’s Almaden Research Centre (San Jose,
CA) in the 1970s
E.g.,
Select all (“*”) columns from the EMPLOYEE table in
which the JOB_CLASSIFICATION field is equal to “C2”
SELECT * FROM EMPLOYEE WHERE
JOB_CLASSIFICATION = “C2”

35. Database Output

36. Popular Database Management Systems for End Users
Microsoft Access
Lotus Approach
Inprise (formerly Borland) dBASE
DBMS Selection Criteria
Database size
Number of concurrent users
Performance
Integration
Features
The vendor
Cost

37. Distributed Databases
Distributed database…
A database in which the actual data may be spread across several
smaller databases connected via telecommunications devices
‘Pretty’ picture

39. Data Warehouse
Data warehouse
A relational database management system designed specifically to support
management decision making
Current evolution of Decision Support Systems (DSSs)
Data mart
A subset of a data warehouse for small and medium-size businesses or
departments within larger companies
Schematic

40. Relational
databases
Hierarchical
databases
Network
databases
Flat files
Spreadsheets
Data
extraction
process
Query and
analysis
tools
Data
warehouse
Data
cleanup
process
End user access

41. Designing a Customer Data Warehouse
Sharply define your goals and objectives before you build the
warehouse
Choose the software that best fits your goals
Determine who/what should be in the database
Develop a plan
Measure results

42. Data Mining Applications
Data mining
The automated discovery of patterns and relationships in a data warehouse
Data mining applications
Market segmentation
Customer queries
Fraud detection
Direct marketing
Market basket analysis
Trend analysis

43. On-Line Analytical Processing (OLAP)
On-line analytic processing (OLAP)
Access to multidimensional databases providing managerially useful
display techniques
Now used to store and deliver data warehouse information
Data warehouse and OLAP
Provides top-down, query-driven analysis
Data mining
Provides bottom-up, discovery-driven analysis

44. Open Database Connectivity (ODBC)
Open database connectivity (ODBC)
A set of standards that ensures software written to comply with
these standards can be used with any ODBC-compliant database
Schematic

45. dBASE
ACCESS database
Lotus 1-2-3 spreadsheet
Paradox database
ODBC Import
ODBC Link
ODBC Export

46. Thank You!