MIS Ch7 Databases
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Transcript of MIS Ch7 Databases
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MANAGEMENT
INFORMATION SYSTEMS
Chapter 7: Storing Organizational Information Databases
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Learning Outcomes
1. Define the fundamental concepts of the relational database model.
2. Evaluate the advantages of the relational database model.
3. Define a database management system and its relationship to a website.
4. Explain why an organization would want to integrate its databases.
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Database Fundamentals
Information is everywhere in an organization
Information is stored in databases
Database = maintains information about various types of:
Objects (i.e. inventory)
Events (i.e. transactions)
People (i.e. employees)
Places (i.e. warehouses)
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Database Fundamentals
Database management system = computer program
used to manage and query a database
Database properties:
Data are managed to ensure integrity and quality
Allows shared access across a community of users
Has a schema
Supports a query language
7-4
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Database Models
Hierarchical database model = information is organized
into a tree-like structure (using parent/child
relationships) in such a way that it cannot have too
many relationships
Network database model = flexible way of representing
objects and their relationships
Relational database model = stores information in the
form of logically related two-dimensional tables
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Entities and Attributes
Entity = person, place, thing, transaction, or event about
which information is stored
Rows in each table contain the entities
In Figure 7.1 CUSTOMER includes Daves Sub Shop and
Pizza Palace entities
Attribute (fields, columns) = characteristics or properties
of an entity class
Columns in each table contain the attributes
In Figure 7.1 attributes for CUSTOMER include Customer
ID, Customer Name, Contact Name
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Keys and Relationships
Primary keys and foreign keys identify the various entity
classes (tables) in the database
Primary key = field (or group of fields) that uniquely
identifies a given entity in a table
Foreign key = primary key of one table that appears an
attribute in another table and acts to provide a logical
relationship among the two tables
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Keys and Relationships
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Advantages of Relational Database
Increased flexibility
Increased scalability and performance
Reduced information redundancy
Increased information integrity (quality)
Increased information security
7-9
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Increased Flexibility
Well-designed database should:
Handle changes quickly and easily
Provide users with different views
Have only one physical view
Physical view = deals with the physical storage of
information on a storage device
Have multiple logical views
Logical view = focuses on how users logically
access information
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Increased Scalability and Performance
Database must scale to meet increased demand, while
maintaining acceptable performance levels
Scalability = refers to how well a system can adapt to
increased demands
Performance = measures how quickly a system performs a
certain process or transaction
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Reduced Information Redundancy
Databases reduce information redundancy
Redundancy = duplication of information or storing the
same information in multiple places
Inconsistency is one of the primary problems with
redundant information
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Increase Information Integrity (Quality)
Information integrity = measures the quality of information
Integrity constraint = rules that help ensure the quality of information
Relational integrity constraint
Business-critical integrity constraint
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Increased Information Security
Information is an organizational asset and must be
protected
Databases offer several security features including:
Password = provides authentication of the user
Access level = determines who has access to the
different types of information
Access control = determines types of user access,
such as read-only access
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Database Management Systems
Database management systems (DBMS) = software
through which users and application programs interact with
a database
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Data-Driven Websites
Data-driven websites = interactive website kept constantly
updated and relevant to the needs of its customers through
the use of a database
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Advantages of Data-Driven Website
Development
Content management
Future expandability
Minimizing human error
Cutting production and update costs
More efficient
Improved stability
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Data-Driven Business Intelligence
BI in a data-driven website
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Integrating Information
Integration = allows separate systems to communicate directly with each other
Forward integration = takes information entered into a given system and sends it automatically to all downstream systems and processes
Backward integration = takes information entered into a given system and sends it automatically to all upstream systems and processes
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Integrating Information Forward Integration
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Integrating Information Backward Integration
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Integrating Information
Building a central repository specifically for integrated information