CIS Database Notes
Introduction to Databases
BDS: Connolly, Begg, Holowczak
Pratt/Adamski
Elmasri/Navathe (3rded.)
Kroenke Book (7thed.)
McFadden (5thed.)
Mata-Toledo / Cushman
Ch. 1 and 2
Ch. 1
Ch. 1 and 2
Chap. 1 and 2
Chap. 1
Schaum's Outlines Ch. 1
Q: What is a Database ?
Answer from BDS: A shared collection of logically related data and descriptions of that data, designed to meet the needs of na organization.
Answer from Elmasri/Navathe:
A Database (DB) is collection of related data - with the following properties:
1. A DB is logically coherent and has some relevant meaning
2. A DB is designed, built and populated with data for a specific purpose
3. A DB represents some aspect of the real world.
We can also say that the database is a model of what the users perceive.
Three main categories of models:
User or Conceptual Models: How users perceive the world and/or the business.
Logical Models: Represent the logic of how a a business operates. For example, the relationship between different entities and the flow of data through the organization. Based on the User's model.
Physical Models: Represent how the database is actually implemented on a computer system. This is based on the logical model.
Database Management System (DBMS)
A Software system that enables users to define, create and maintain the database and provides controlled access to the database.
Database System (DBS) contains:
The Database +
The DBMS +
Application Programs (what users interact with)
Note: We will explore how the application, DBMS and database are distributed in the Database System Architecutres module later in the semester.
File Systems
File System: A collection of individual files accessed by applications programs
Limitations of a File System:
Separated and Isolated Data - Makes coordinating, assimilating and representing data difficult
Data Duplication - Wastes space and can lead to data integrity (inconsistency) problems
Application Program Dependencies
BDS: Connolly, Begg, Holowczak
Pratt/Adamski
Elmasri/Navathe (3rded.)
Kroenke Book (7thed.)
McFadden (5thed.)
Mata-Toledo / Cushman
Ch. 1 and 2
Ch. 1
Ch. 1 and 2
Chap. 1 and 2
Chap. 1
Schaum's Outlines Ch. 1
Q: What is a Database ?
Answer from BDS: A shared collection of logically related data and descriptions of that data, designed to meet the needs of na organization.
Answer from Elmasri/Navathe:
A Database (DB) is collection of related data - with the following properties:
1. A DB is logically coherent and has some relevant meaning
2. A DB is designed, built and populated with data for a specific purpose
3. A DB represents some aspect of the real world.
We can also say that the database is a model of what the users perceive.
Three main categories of models:
User or Conceptual Models: How users perceive the world and/or the business.
Logical Models: Represent the logic of how a a business operates. For example, the relationship between different entities and the flow of data through the organization. Based on the User's model.
Physical Models: Represent how the database is actually implemented on a computer system. This is based on the logical model.
Database Management System (DBMS)
A Software system that enables users to define, create and maintain the database and provides controlled access to the database.
Database System (DBS) contains:
The Database +
The DBMS +
Application Programs (what users interact with)
Note: We will explore how the application, DBMS and database are distributed in the Database System Architecutres module later in the semester.
File Systems
File System: A collection of individual files accessed by applications programs
Limitations of a File System:
Separated and Isolated Data - Makes coordinating, assimilating and representing data difficult
Data Duplication - Wastes space and can lead to data integrity (inconsistency) problems
Application Program Dependencies