Transcript Management Information Systems

Chapter 8
Data and Knowledge Management
Management Information Systems, 4th Edition
1
Managing Digital Data
• The Traditional File Approach
– Disadvantages
• Program/Data Dependency
• Data Redundancy
• Data Integrity
• Moving to Databases
– Database Management System (DBMS)
• Queries: Request data from specified fields
• Security: Giving users different views addresses
security issue
Management Information Systems, 4th Edition
2
Managing Digital Data (Cont)
Management Information Systems, 4th Edition
3
Managing Digital Data (Cont.)
Management Information Systems, 4th Edition
4
Traditional Files vs. Databases: Pros
and Cons
• Traditional File Advantages
– Simplicity
– Efficiency
– Customization
• Database Advantages
–
–
–
–
Reduced data redundancy
Application/data independence
Better control
Flexibility
Management Information Systems, 4th Edition
5
The Hierarchical 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
Management Information Systems, 4th Edition
6
The Hierarchical Model
Management Information Systems, 4th Edition
7
The Network Model
• Allows a record to be linked to more than one
parent
• Supports many-to-many relationships
• Advantage of the network model
– Reduced data redundancy
• Disadvantages of the network model
– Complicated to build and difficult to maintain
– Difficult to maintain and navigate
Management Information Systems, 4th Edition
8
The Network Model (Cont.)
Management Information Systems, 4th Edition
9
The Relational Model
• Consists of tables; links among entities are
maintained with foreign keys
• Advantages of relational databases
– Same advantages of a network database without the
complications
– Easier to conceptualize and maintain
– Virtually all DBMSs offered for microcomputers
accommodate the relational model
Management Information Systems, 4th Edition
10
The Relational Model (Cont.)
Management Information Systems, 4th Edition
11
The Object-Oriented Structure
• Useful for data and information that cannot be
organized into fields
• Does not store records, but data objects
• Advantages include ability to represent data
dynamically
• Disadvantages include dependence between
applications and data
Management Information Systems, 4th Edition
12
Components of Database
Management Systems
• The Schema
– Describes the structure of the database
• The Data Dictionary (Metadata)
– Maintains all information supplied by the developer
when constructing the schema
Management Information Systems, 4th Edition
13
Relational Databases:
Design and Keys
• Data Modeling
– Analyzing data and identifying relationships
– Entity Relationship (ER) Diagram, a graphical
representation of all entity relationships
– Understand symbols when reviewing a diagram
– Key: a field whose value identify records
• Primary Key
• Linking
Management Information Systems, 4th Edition
14
Relational Databases:
Design and Keys (Cont.)
Management Information Systems, 4th Edition
15
Relational Databases:
Design and Keys (Cont.)
Management Information Systems, 4th Edition
16
Components of Database
Management Systems
• The Schema
– Describes the structure of the db
• Names, types of fields, general relationships
– Types of data
• Numeric, alphanumeric, graphic, time-related
– Building a Database
Management Information Systems, 4th Edition
17
Components of Database
Management Systems (Cont.)
Management Information Systems, 4th Edition
18
The Data Dictionary
• All information supplied by db developer in the
schema is maintained here
– Table names
– Record names and types
– Field names and types
– Relationships among record types
– Who is responsible for updating the db
Management Information Systems, 4th Edition
19
The Data Dictionary (Cont.)
Management Information Systems, 4th Edition
20
Data Definition Language (DDL)
• Used to construct the schema
• Usually transparent to user of modern relational
DBMS
Management Information Systems, 4th Edition
21
Data Manipulation Language
(DML)
• Software used to query the database
• Either enter a statement requesting information, or
a Query by Example (QBE)
• Programmers use this for developing applications
Management Information Systems, 4th Edition
22
Data Manipulation Language
(DML)
Management Information Systems, 4th Edition
23
Relational Operations
• Data Manipulation
– Select, Project, Join
• Structured Query Language (SQL)
– International standard DDL and DML for
relational DBMS
Management Information Systems, 4th Edition
24
Relational Operations (Cont.)
• SQL (cont.)
– Advantages
– 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.
Management Information Systems, 4th Edition
25
Database Architecture
• Distributed Databases
– Replication
• Full copy of the entire database is stored at all sites
– Fragmentation
• Parts of database are stored where they are most
often accessed
Management Information Systems, 4th Edition
26
Database Architecture (Cont.)
Management Information Systems, 4th Edition
27
Database Architecture (Cont.)
Management Information Systems, 4th Edition
28
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
Management Information Systems, 4th Edition
29
Databases on the Web
• Catalogs
• Libraries of books, articles, CDs, and movie
clips
• Directories
• Client lists and profiles
• Package tracking
• Customer relationship management
• Financial transactions databases
Management Information Systems, 4th Edition
30
Databases on the Web (Cont.)
• Points to Consider
• Which application to use
• How to ensure Web surfers do not interfere with
database updates
• How to maintain security
Management Information Systems, 4th Edition
31
Data Warehousing
• Data warehouse: a collection of data that supports
management decision making
• Data Mart: smaller collection of data focusing on a
particular subject or department
Management Information Systems, 4th Edition
32
Data Warehousing (Cont.)
• From Database to Data Warehouse
– Transactional db usually not suitable for analysis
because they contain current, not historical data
– Hardware must meet capacity needs
– Data and software and scalability must be
considered
Management Information Systems, 4th Edition
33
Phases in Building a Data
Warehouse
• Extraction Phase
– Builders create the files from transactional db and
save on server
• Cleansing Phase
– Data is made consistent
• Loading Phase
– Builders transfer files to data warehouse database
Management Information Systems, 4th Edition
34
Data Mining and Online Analysis
• Data mining
– Sequence or path analysis
– Classification
– Clustering
– Forecasting
Management Information Systems, 4th Edition
35
Data Mining and Online Analysis
(Cont.)
Management Information Systems, 4th Edition
36