FEN 2015-08-31 1

Introduction to the database field:

Applications, concepts and terminology

Seminar:Introduction to relational databases

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Databases and Database Applications

Textual and numerical databasesMultimedia DatabasesGIS (Geographic Information Systems)Data WarehouseReal-time and active databasesAnd many-many more

FEN 2015-08-31

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What is a Database?

A database is a collection of related data.A database is a logical coherent collection of data with some inherent meaning. Hence a random collection of data is not a database. A database is designed, built and populated with data for a specific purpose for a specific group of users with requirements for specific applications.A database represents some aspect of the real word, sometimes called the miniworld or domain.

FEN 2015-08-31

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What is a DBMS?

A DBMS (Database Management System) is a collection of programs that enables the users to create and maintain databases.This involves

Defining a database (data types, structures and constraints) and handling meta data.Storing the data on some suitable storage medium and controlling the storage. Manipulating the database (executing queries and updating the database)Sharing the database allowing multiple users and application to access the database simultaneously. Providing interfaces to interactive users and/or application programs.

FEN 2015-08-31

Sometimes called a Database Server or Database Engine

Do you know some DBMS?

For instance:OracleMySQLMS SQL ServerPostgreSQL

and many more

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What is a Database System?

A database system is a database and a database management system put together:

Database + DBMS == Database system

FEN 2015-08-31

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Overview

DatabaseDBMSDatabase System

FEN 2015-08-31

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Data Models

Database systems are build upon a data model.A data model is a collection of concepts used to describe the structure of a database.A data model provides data abstraction, hides storage details and gives users (and developers) a conceptual view of the database.A data model should provide means to describe:

Structure Data typesRelationshipsConstraintsOperations

FEN 2015-08-31

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Data Models

Legacy (pre-relational)HierarchicalNetworkRecord based

Relational

Post-relationalKey-Value storesObject orientedObject-relationalTemporalXMLCubes in Data Warehouse...

FEN 2015-08-31

The relational model is still very central and

the most used.

Also known as NoSQL databases (NoSQL

means Not Only SQL).

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Relational DatabasesAll data is organised in tables with atomic valuesAssociations are represented by primary key/foreign key connectionsEvery operation operates on tables and returns tables

FEN 2015-08-31

Small exercise (5 min..):• Describe step by step (which tables are

used and how) how you will retrieve this information:

• When did Mr Smith attend the “Intro to Computer Science” course, who was the instructor and what grade did he receive?