the database environment where is the wisdom we have lost in knowledge? where is the knowledge we...
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THE DATABASE ENVIRONMENT
Where is the wisdom we have lost in knowledge? Where is the knowledge we have lost in information.
~ T.S. Eliot ~
Learning Objectives
Concretize the concepts of data, information, data management and metadata
Explain what a database is and why databases are important
Describe a database management system Differentiate between the DBMS and a database Describe the different data models and abstraction
layers Explain the similarities and differences among
DBMS products Explain DBMS history and modern uses Describe how data is physically stored in primary
and secondary storage
Activity: Data or Meta-Data?
1. A Zip Code: 132442. A Zip Code is 5 Characters XXXXX3. A List of First Names: Tom, Dick, Harry4. A Picture, Like This One:5. The Name of the Picture
file FrostTrees.jpg6. When you place an order, the quantity
of the item ordered must be a number >0
Something strange and confusing:
Data can be information: $5 (the amount of money in my wallet)
Information can be data: I calculate student final grades, then place
them on a form sent to the registrar’s office.
Metadata can be data: The names of MP3 files in your personal
collection.
Actually it’s all about context!
Elements of a Database
Meta-Data
Data
DatabaseData-Management
Data “In”
Information “Out”
End-User
DBMS is software. It stores the data/meta data and “enables” data-management
Clarification via Family Guy
Brian can write his novel on a typewriter or w/pen and paper.
But there are obvious advantages to using word processing software.
Most databases use DBMS’s just like most papers are written with word processors
Database Brian’s NovelDBMS WP Software
Enterprise DBMS Market Share
Product Share
Oracle 44.4%
IBM (DB2) 21.2%
Microsoft (SQL Server) 18.6%
Others: (Sybase, NCR Terdata, etc…) 5.9%Open Source (MySQL, PostgreSQL, etc…)
9.9%* Source: Computerworld 2007
Data Models: Abstraction Levels
Conceptual
Internal
External
Physical
Logical
Highly AbstractHardware and Software
Independent
Somewhat Abstract Hardware IndependentSoftware Dependent
Not Abstract (Concrete)Hardware and Software Dependent
Elements of the DBMS Approach
Enterprise Data Model Graphical model showing high-level entities and
relationships for the organization Relational Databases
Database technology involving tables (relations) representing entities and primary/foreign keys representing relationships
Use of Internet Technology Networks and telecommunications, distributed
databases, client-server and 3-tier architectures Database Applications
Application programs used to perform database activities CRUD for database users