Transcript Managing Data Resources

Managing Data Resources
Chapter 7
Data hierarchy
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Bit
Byte
Field
Record
File
Database – a group of related files
Basic data concepts
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An entity is a person, place, thing or
event on which we maintain
information, for example, a student
record
An attribute is a field describing a
characteristic or quality of an entity, for
example, student name
A key field is an identifier field
Traditional File Environment
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Manually create several different data
management programs
As compared with modern database
management systems, traditional file
environment has many problems.
Problems with the traditional file
environment
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Data redundancy and confusion
Program-data dependence
Lack of flexibility
Poor security
Lack of data-sharing and availability
The database environment
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Avoid problems happened in the traditional file
environment
A single database serves multiple applications and
also easily allow users to draw together all the
information for other applications
The database management system acts as the
interface between the application programs and the
data
But is much more expensive and need professional
management
Can rent it through application software providers
(ASP)
Components of a DBMS
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A data definition language
A data manipulation language
A data dictionary
A data definition language
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Is used to specify the content and
structure of the database
Define each data element
A data manipulation language
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Is used to manipulate data in the
database for some application through
some application software
Structured query language, or SQL, is a
famous data manipulation language
Data dictionary
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An automated or manual file that stores
definition of data elements and data
characteristics such as usage, physical
representation, ownership,
authorization and security
Database trends
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OLAP vs. OLTP – On line transaction
processing does not analyze data using
multidimensional data analysis called on
line analytical processing
Data warehouses are databases that
store current and historical data of
potential interest to managers
throughout the company
Benefits of data warehouses
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Improved information
Easy access
The ability to model and remodel the
data in the warehouse
Uses OLAP and datamining to help
refocus businesses
Linking internal DB to the web
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Legacy system
Middle ware
SQL
Application server customer program
Internet
Web browser
Key organizational elements in
the database environment
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Data administration
Data planning and modeling
methodology
Database technology and management
users
Data administration
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Data as an organizational resource
Administration means to develop
information policy, to plan for data
including overseeing database design
and monitoring how information system
specialists and end-users use data
The head of it is called CIO
Database administration
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Define and organize database structure
and content
Develop security procedures to
safeguard the database
Develop database documentation
Maintains the database management
software