1. MANAGING DATA RESOURCES
CHAPTER 8.
MANAGING DATA RESOURCES

2. FILE ORGANIZATION BIT: Binary Digit (0,1;Y,N;On, Off)
BYTE: Combination of BITS which represent a CHARACTER
FIELD: Collection of BYTES which represent a Fact
RECORD: Collection of FIELDS
which reflect a TRANSACTION
FILE: A Collection of Similar
RECORDS

3. The layout of a personnel file in traditional file organization.
Managing Digital Data
The layout of a personnel file in traditional file organization.

4. FILE ORGANIZATION UPDATING SORTING
DATABASE: An Organization’s Electronic
Library of FILES
Primary FIELD or Key: Field in Each Record Uniquely Identifies
THIS Record For RETRIEVAL
UPDATING
SORTING

5. TRADITIONAL FILE ENVIRONMENT (FLAT FILE)
DATA REDUNDANCY
PROGRAM / DATA DEPENDENCY
LACK OF FLEXIBILITY
POOR SECURITY
LACK OF DATA SHARING & AVAILABILITY
Different information making up a student record retained in three different sites.

6. DATABASE MANAGEMENT SYSTEM (DBMS)
SOFTWARE TO CREATE & MAINTAIN DATA
*** ENABLES BUSINESS APPLICATIONS TO
EXTRACT DATA
*** INDEPENDENT OF SPECIFIC COMPUTER
PROGRAMS
DBMS

7. Managing Digital Data Traditional Files vs. Databases: Pros and Cons
Traditional File Advantages
Simplicity
Efficiency
Customization
Database Advantages
Reduced data redundancy
Application/data independence
Better control
Flexibility

8. COMPONENTS OF DBMS: DBMS THE SCHEMA: describe the structure of the
Database.
DATA DEFINITION LANGUAGE:
Defines Data Elements in Database
and Used to construct the schema
DATA MANIPULATION LANGUAGE:
Manipulates Data for Applications
DATA DICTIONARY:
Maintains all information supplied by the developer when constructing the schema *
DBMS

9. Data Definition Language (DDL)
Data definition language to create a schema in NOMAD

10. Components of Database Management Systems
Data Manipulation Language (DML)
Used to query the database
Figure 8.14 A Paradox query by example

11. DATA DICTIONARY
A typical data dictionary for a staff file

12. ADVANTAGES OF DBMS: DBMS * REDUCES COMPLEXITY REDUCES DATA REDUNDANCY
CENTRAL CONTROL OF DATA DEFINITIONS
REDUCES PROGRAM / DATA DEPENDENCE
REDUCES DEVELOPMENT / MAINTENANCE COSTS
ENHANCES SYSTEM FLEXIBILITY
INCREASES ACCESS / AVAILABILITY OF INFORMATION *
DBMS

13. Database Models HIERARCHICAL DATA MODEL
Records are related hierarchically –
each category is a subcategory of the next level up
Disadvantages of hierarchical databases
To retrieve a record, a user must start at the root and
navigate the hierarchy.
If a link is broken, the entire branch is lost.
Requires considerable data redundancy
ROOT
FIRST CHILD
2nd CHILD
Ratings
Salary
Compensation
Job
Assignments
Pension
Insurance
Health
Benefits
Employer

14. NETWORK DATA MODEL VARIATION OF HIERARCHICAL MODEL
Allows a record to be linked to more than one parent
USEFUL FOR MANY-TO-MANY RELATIONSHIPS
NETWORK A B C 1 2

15. RELATIONAL DATA MODEL
Consists of tables; links among entities are maintained with foreign keys
DATA IN TABLE FORMAT
RELATION: TABLE
TUPLE: ROW (RECORD) IN TABLE
FIELD: COLUMN (ATTRIBUTE) IN TABLE *

16. TYPES OR RELATIONS ONE-TO-ONE: STUDENT ID ONE-TO-MANY: CLASS STUDENT AB C
MANY-TO-MANY:
STUDENT A B C
CLASS 1 2

17. Relational Operations
Data Manipulation
Select : is the selection of records that meets certain condition.
Project: is the selection of certain columns from a table.
Join : is the joining of data from multiple tables.
Structured Query Language (SQL)
International standard DDL and DML for relational DBMS.
Advantages of using SQL
Users do not need to learn different DDLs and DMLs.
SQL can be embedded in widely used 3rd generation languages, increasing efficiency and effectiveness.
Programmer not forced to rewrite statements since SQL statements are portable.

18. Advantages and disadvantages of database models

19. Database Architecture
Shared Resource and Client/Server Systems
Four basic client/server models
Applications run at a server
Applications run on local PCs
Applications run on both the local PCs and the server
Applications and key elements of the database are split between the PCs and the server

20. Database Architecture
Distributed Databases
Replication :Full copy of the entire database is
stored at all sites
A replicated database: each computer holds a copy of the entire database

21. Database Architecture
Fragmentation: Parts of database are stored where they
are most often accessed
A fragmented database: each computer holds only the part of the database that is most frequently accessed by the local users

22. Web Databases Databases on the Web
Catalogs
Libraries
Directories
Client lists and profiles
When linking a database to the Internet, consider
Which application to use
How to ensure Web surfers do not interfere with database updates
How to maintain security

23. Data Warehousing Data warehouse Data Mining
Collection of data that supports management decision making
Phases in Building a Data Warehouse
Extraction Phase
Cleansing Phase
Loading Phase
Data Mining
Selecting, exploring, and modeling data to discover unknown relationships

24. Data Warehousing

25. Data-Mining
Potential applications of data-mining

26. DATABASE ADMINISTRATION
DEFINES & ORGANIZES DATABASE STRUCTURE AND CONTENT
DEVELOPS SECURITY PROCEDURES
DEVELOPS DATABASE DOCUMENTATION
MAINTAINS DBMS *

27. Ethical and Societal Issues A Too-Risky Info Highway
Out of Hand -- Out of Control
DBMSs allow organizations to collect, maintain, and sell vast amounts of private personal data easily.
Where is the Information Going?
Many consumers provide information daily without being aware of where it is actually going.
The Upside
Database technology enables better and faster services.