Introduction to Database Systems

Июль 28, 2022

Главная
Разное
Introduction to Database Systems

Содержание

2. A. Silberschatz, H. F. Korth, S Sudarshan, Database System Concepts, 5th Ed., McGrow Hill, 2005 http://www.db-book.com
3. File Management vs Database Management (why do we need database?) Advantages of Database systems: storage persistence,
4. You cannot avoid it and it’s everywhere! You can say it actually makes the current society
6. Relational DBMS companies – Oracle, Sybase – are among the largest software companies in the world.
7. Imagine you want build an online shopping website Maintain products/categories (price, picture, properties, …) Customers accounts
8. Any question (access) on the data is a small program!! Data redundancy Data is not isolated
9. Allow access to the file only to the authorized personnel Ability to restrict access to parts
10. A database constraint is a logical constraint about the data expressed in a logical language. STUDENT.AGE
11. Collection of Files Hierarchical 60’s 70's 80's 90’s now Relational Choice for most new applications Object
12. Persistent Storage – Database not only provides persistent storage but also efficient access to large amounts
13. Airline Reservation Systems – Data items are: single passenger reservations; Information about flights and airports; Information
14. Client – Server architecture DBMS serves as a server and client queries are sent to servers
15. Coordinates all the activities of the database system; the database administrator has a good understanding of
16. Naïve – do not know about database too much, invoke application programs that are prepared already
17. The enterprise data can be described as a set of entities and a set of relationships
18. Example of schema in the entity-relationship model Entity-Relationship Model
20. Скачать презентацию

Слайд 2

A. Silberschatz, H. F. Korth, S Sudarshan,
Database System Concepts, 5th

Ed., McGrow Hill, 2005
http://www.db-book.com
Hector Garcia-Molina, Jeffrey D. Ullman, Jennifer Widom,
Database Systems, The Complete Book, Prentice Hall, 2002
http://www-db.stanford.edu/~ullman/dscb.html
Class notes

References

Слайд 3

File Management vs Database Management (why do we need database?)
Advantages

of Database systems: storage persistence,
programming interface, transaction management
Data Model (What is Data?)
Database Language (How to manipulate data?)
DBMS Architecture and Database System Components (How can you build a billion-dollar software, like Oracle? Or you can get it free, mySQL?)
Users classification (What you can do and what you cannot do?)

Database Overview

Слайд 4

You cannot avoid it and it’s everywhere!
You can say it actually

makes the current society and your life work!
Banking/Credit card /Social Security Info…
Online shopping/booking…

Where are databases?

Слайд 5

Слайд 6

Relational DBMS companies – Oracle, Sybase – are among the largest

software companies in the world.
IBM offers its relational DB2 system. With IMS, a nonrelational system, IBM is by some accounts the largest DBMS vendor in the world.
Microsoft offers SQL-Server, plus Microsoft Access for the cheap DBMS on the desktop, answered by “lite” systems from other competitors.
OpenSource: mySQL, postgreSQL

The DBMS Marketplace

Слайд 7

Imagine you want build an online shopping website
Maintain products/categories (price, picture,

properties, …)
Customers accounts
File is uninterpreted, unstructured collection of information
File operations: delete, catalog, create, rename, open, close, read, write, find, …
Access methods: Algorithms to implement operations along with internal file organization
Examples: File of Customers, File of Products; Access method: implementation of a set of operations on those files

Pre-Database Era: Stone Age of Data

Слайд 8

Any question (access) on the data is a small program!!
Data

redundancy
Data is not isolated from the access implementation (different format…)
Multiple application (concurrent program) on the same file

File Management System Problems

Слайд 9

Allow access to the file only to the authorized personnel
Ability to

restrict access to parts of the record
Ability to control operation usage by different users
Protection from unauthorized use
Protection from the derivation of unauthorized information

Security Problems

Слайд 10

A database constraint is a logical constraint about the data expressed

in a logical language.
STUDENT.AGE >15
If (STUDENT.CLASS ==cs43005) then (STUDENT.PRIOR_CLASS ==cs31001)
Database is consistent if data at each time satisfies all integrity constraints.
Input to any application is a set of consistent data. An application output is a set of consistent data.

Data Integrity

Слайд 11

Collection of Files
Hierarchical
60’s
70's
80's
90’s
now
Relational
Choice for most new applications
Object Bases
Knowledge Bases
Network

Слайд 12

Persistent Storage – Database not only provides persistent storage but also

efficient access to large amounts of data
Programming Interface – Database allows users to access and modify data using powerful query language. It provides flexibility in data management
Transaction Management – Database supports a concurrent access to the data

Advantages of Databases

Слайд 13

Airline Reservation Systems – Data items are: single passenger reservations; Information

about flights and airports; Information about ticket prices and tickets restrictions.
Banking Systems – Data items are accounts, customers, loans, mortgages, balances, etc. Failures are not tolerable. Concurrent access must be provided
Corporate Records – Data items are: sales, accounts, bill of materials records, employee and their dependents

Early Database Applications

Слайд 14

Client – Server architecture
DBMS serves as a server and client queries

are sent to servers
Where to locate servers
Multimedia Applications
Multidatabase Applications
Data Warehouses
It’s everywhere!!

Modern Database Applications

Слайд 15

Coordinates all the activities of the database system; the database administrator

has a good understanding of the enterprise’s information resources and needs.
Database administrator's duties include:
Schema definition
Storage structure and access method definition
Schema and physical organization modification
Granting user authority to access the database
Specifying integrity constraints
Acting as liaison with users
Monitoring performance and responding to changes in requirements

Data Administrator

Слайд 16

Naïve – do not know about database too much, invoke application

programs that are prepared already
Application Programmers – know how to interact with the system but may not know how DBMS is designed
Sophisticated users that know advanced use of the system and can use the system and packages on the top of the system
DBMS system users – write specialized database applications that do not fit into the traditional data processing framework

Database Users

Слайд 17

The enterprise data can be described as a set of entities

and a set of relationships between them.
Entity – a data that pertains to, or describes some component of the enterprise
Each entity is characterized by a set of attributes
Relationship – describes an interconnection between different entities
Entity Set – a set of entities that are characterized by the same entity definition
Relationship Set – a set of relationships of the same type

A Little Design Methodology: Entity-Relationship Model

Слайд 18