Michael Emmerich Leiden Institute for Advanced Computer Science, Leiden University pptx

Introductory example Overview of the course Historical development of databases What is a database?. Database = A character in ’The simpsons’ I Database = a collection of data pieces and

Introductory example

Overview of the course

Historical development of databases

DatabasesIntroduction

Michael EmmerichLeiden Institute for Advanced Computer Science, Leiden

University

January 17, 2012

Michael T M Emmerich Databases

Introductory example Overview of the course Historical development of databases

Database people

I dr Michael Emmerich - Assistant Professor(emmerich@liacs.nl)

I drs Hossein Rahmani - PhD Student

I drs Martin Wimmers - Master Student

I N.N - Master Student

I our email: databases@liacs.nl

Introductory example Overview of the course Historical development of databases

Course regulations, grades

I Assignment 1: Basics and Practice: Modeling and SQL DMLand DDL

I Assignment 2: Advanced Topics: XML, Query Optimization,Transactions, Schema Refinement

I Exam (June, August)

I Final Grade = 0.2 * First Assignment + 0.2 * SecondAssignment + 0.6 Exam

I Assignments can be done in pairs, but also alone

Michael T M Emmerich Databases

Introductory example Overview of the course Historical development of databases

Introductory example Overview of the course Historical development of databases

What is a database?

I What is a database? Do you know examples?

Database = A character in ’The simpsons’

I Database = a collection of data pieces and meta-information(schema) on how this data is organized

I Database Management System = software used to managethe database

Michael T M Emmerich Databases

Introductory example Overview of the course Historical development of databases

What is a database?

I What is a database? Do you know examples?

Database = A character in ’The simpsons’

I Database = a collection of data pieces and meta-information(schema) on how this data is organized

I Database Management System = software used to managethe database

Introductory example Overview of the course Historical development of databases

What is a database?

I What is a database? Do you know examples?

Database = A character in ’The simpsons’

I Database = a collection of data pieces and meta-information

(schema) on how this data is organized

I Database Management System = software used to managethe database

Michael T M Emmerich Databases

Introductory example Overview of the course Historical development of databases

What is a database?

I What is a database? Do you know examples?

Database = A character in ’The simpsons’

I Database = a collection of data pieces and meta-information

(schema) on how this data is organized

I Database Management System = software used to manage

the database

Introductory example

Overview of the course Historical development of databases

How to organize address data?

Michael T M Emmerich Databases

I By means of which information should we sort the data andidentify data records?

I How can we deal with more complex data? (e.g relationsbetween persons: A knows B, B is married to C)?

I How can we ensure consistency and avoid redundant storage?

I How can we make sure that nobody reads our addresses?

I How can many people edit the address database concurrentlyfrom the internet?

Introductory example

Overview of the course

Historical development of databases

Overview of the course

I SQL DDL - how to define data in a databases?

I SQL Queries - how to retrieve data from a database andprogram constraints and triggers?

Michael T M Emmerich Databases

Introductory example

Overview of the course

Historical development of databases

Overview of the course

(2) Application programming

I Embedded SQL - how to call databases from C++ programs?

I JDBC - how to build database-backed internet applications?

I Large Objects - how to maintain pictures, sounds, etc inDatabases?

I Excursion: XML - an alternative way to build databases

Introductory example

Overview of the course

Historical development of databases

Overview of the course

(3) Theoretical aspects and distributed databases

I Algebra and calculus - how to reason formally about SQLqueries?

I Query optimization and indexes - how to make data accessefficient?

I Schema refinement - how to minimize redundancy?

I Transaction management - how to ensure consistency if manypeople use database at the same time?

Michael T M Emmerich Databases

Introductory example

Overview of the course

Historical development of databases

Overview of the course

(4) Advanced topics ( if time is left)

I Data-Mining - how to obtain patterns and knowledge in largedatabases?

I ProLog - how to allow for more difficult queries in systemscombining rules and facts?

I Data-warehousing - how to build systems that integrateseveral databases?

I your choice?

Introductory example Overview of the course

Historical development of databases

From ancient to modern

I Origins are non-electronical: Oral tradition, stone-plates,books, libraries, microfiche, etc

I not to be ingnored, many concepts/principles developed then

- look at town library’s organization!

I often hierarchical sorting of information (efficient access inlogarithmic time)

Michael T M Emmerich Databases

Introductory example Overview of the course

Historical development of databases

The early days

I 1960s: Computers become available for companies

I First database systems store data sequentially on punch cards

I Two main data-models emerge - network model (CODASYL)and hierarchical model (IBM) are developed

I Emphasize is on the physical organization and direct access ofthe data

I Change of data organization and record structure requirescomplete rewrite

I Data and programs get separated

I SABRE system by IBM and American Airlines is developed as

a major application

Introductory example Overview of the course

Historical development of databases

Towards the relational model

Edgar Codd

Larry Ellison Michael T M Emmerich Databases

Introductory example Overview of the course

Historical development of databases

Towards the relational model

I E F Codd (to that time employee at IBM) proposed

relational database model - e.g using tables with a schema toorganize data

I The relational model disconnects the data (physical storagemethod) from its schema (logical organization)

I This system has been standard since

I First implementation of relational model by Berkeley

University: Ingres

I First commercial exploitation of relational model by LarryEllisons Relational Software Inc called Oracle V2 introducesStructured Query Language (SQL)

I IBM sticks long time with hierarchical models, and much laterintroduces System R

Introductory example Overview of the course

Historical development of databases

Conceptual data models

I The conceptual model is a high level, often graphical,description of data

I In database design conceptual models are mapped to logicalmodels which are mapped to physical description of data

I Peter Pin-Chan Chen (1976) introduced Entity-Relationshipmodel (ER-model) as an universal graphical language todescribe data

Michael T M Emmerich Databases

Introductory example Overview of the course

Historical development of databases

Further evolution of databases

I 80ties: SQL develops and becomes standard

I New produts: Sybase, Paradox, Dbase-III (later FoxPro),System R/R+, IBM-DB2, Watcom SQL, etc

I Simple databases for personal computer arise, such as

Excel/Access

I 1990ties: The internet emerges and with it web-based

database technology

I Transaction processing and distributed DBMS gain importance

I Multimedia databases emerge

I large scale , often participatory, internet applications based ongigantic databases emerge (EBAY, Google*, Wikipedia,researchindex etc etc.)

I new, open, data formats and models are discussed:

WikiMedia, XML etc

Introductory example Overview of the course

Historical development of databases

Server-Farms

Figure: A server-farm for a database-backed internet application

Michael T M Emmerich Databases