Lecture 1 Introduction to Database (updated 22/2/2016) 21/2/2014TMC2034 Database Concept and Design1

Objectives In this chapter, you will learn: Data vs information What a database is? File system vs Database A Database System 21/2/2014TMC2034 Database Concept and Design2

Data vs Information 21/2/2014TMC2034 Database Concept and Design3

Data vs. Information Data (singular or plural) are raw facts Raw data - Not yet been processed to reveal the meaning Building blocks of information Information requires context to reveal meaning Eg, 123° 43' " W Raw data must be formatted for storage, processing, and presentation Data are the foundation of information, which is the bedrock of knowledge 21/2/2014TMC2034 Database Concept and Design4

Data vs. Information (cont’d.) Information produced by processing data Information used to reveal meaning in data Accurate, relevant, timely information is the key to good decision making Good decision making is the key to organizational survival Data management: focuses on proper generation, storage, and retrieval of data 21/2/2014TMC2034 Database Concept and Design5

Why do I care about databases? Good decisions require good information derived from raw facts Data is managed most efficiently when stored in a database Databases solve many of the problems encountered in data management Used in almost all modern settings involving data management: Business Research Administration Important to understand how databases work and interact with other applications 21/2/2014TMC2034 Database Concept and Design6

What a database is? 21/2/2014TMC2034 Database Concept and Design7

What a Database is? Database: shared, integrated computer structure that stores a collection of: End-user data: raw facts of interest to end user Metadata: data about data Provides description of data characteristics and relationships in data Complements and expands value of data Database management system (DBMS) Collection of programs Manages the database structure Controls access to data stored in the database 21/2/2014TMC2034 Database Concept and Design8

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File Systems and Databases 21/2/2014TMC2034 Database Concept and Design10

A Simple Database Everyone Can Do – Flat File 21/2/2014TMC2034 Database Concept and Design11

Flat file When data grow, processing may be difficult A dedicated program may create to read the flat file database Read line by line, fields are separated using a separator However, flat file database is subjected to structural, data dependence and data redundancy. 21/2/2014TMC2034 Database Concept and Design12

Evolution of File System Data Processing Reasons for studying file systems: Complexity of database design is easier to understand Understanding file system problems helps to avoid problems with DBMS systems Knowledge of file system is useful for converting file system to database system File systems typically composed of collection of file folders, each tagged and kept in cabinet Organized by expected use 21/2/2014TMC2034 Database Concept and Design13

A File System 21/2/2014TMC2034 Database Concept and Design14

Computerized File Systems 21/2/2014TMC2034 Database Concept and Design15

Evolution of File System Data Processing (cont'd.) Contents of each file folder are logically related Manual file systems Served as a data repository for small data collections Cumbersome for large collections Computerized file systems Data processing (DP) specialist converted computer file structure from manual system Wrote software that managed the data Designed the application programs 21/2/2014TMC2034 Database Concept and Design16

Evolution of File System Data Processing (cont'd.) Initially, computer file systems resembled manual systems As number of files increased, file systems evolved Each file used its own application program to store, retrieve, and modify data Each file was owned by individual or department that commissioned its creation 21/2/2014TMC2034 Database Concept and Design17

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A Simple File System 21/2/2014TMC2034 Database Concept and Design20

File System Redux: Modern End-User Productivity Tools Ubiquitous use of personal productivity tools can introduce the same problems as the old file systems Microsoft Excel Widely used by business users Users have become so adept at working with spreadsheets, they tend to use them to complete tasks for which spreadsheets are not appropriate – database substitute 21/2/2014TMC2034 Database Concept and Design21

Problems with File System Data Processing 21/2/2014TMC2034 Database Concept and Design22 Lengthy development timesDifficulty of getting quick answersComplex system administrationLack of security and limited data sharingExtensive programming

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A Database System 21/2/2014TMC2034 Database Concept and Design24

Database Systems An integrated database environment Access to the databases is controlled by a software package called database management system (DBMS) DBMS eliminates most of file system’s problems Current generation DBMS software: – Stores data structures, relationships between structures, and access paths – Defines, stores, and manages all access paths and components Logically related data stored in a single logical data repository Physically distributed among multiple storage facilities 21/2/2014TMC2034 Database Concept and Design25

Contrasting Database and File Systems 21/2/2014TMC2034 Database Concept and Design26

The Database System Environment 21/2/2014TMC2034 Database Concept and Design27

Role of the DBMS Serve data to end user Interact DBMS directly or indirectly Use SQL to retrieve the data from the DBMS Allow writing applications for other users Java, C, C++, C# … Allow designing, creating and maintaining the database with ease Carry out the task by database administrator (DBA) 21/2/2014TMC2034 Database Concept and Design28

Advantages of Database Systems (1) 21/2/2014TMC2034 Database Concept and Design29 Allow sharing of dataControl of redundancyEnsure data consistencyImprove data standardsMore control over concurrency

Advantages of Database Systems (2) 21/2/2014TMC2034 Database Concept and Design30 Better data securityImproved data integrityBetter backup and recovery proceduresFast development of new applicationsBetter data accessibility

Disadvantages of Database Systems 21/2/2014TMC2034 Database Concept and Design31 Increased costsManagement complexityMaintaining currencyVendor dependenceFrequent upgrade/replacement cycles

Preparing for Your Database Professional Career 21/2/2014TMC2034 Database Concept and Design32

Question? 21/2/2014TMC2034 Database Concept and Design33

Which is the following businesses require database? An ice-cream store A tuition center A computer hardware and repair store A pharmacy A car spare-part store A florist store A Real estate corporation A clinic A second hand car dealer A furniture store 21/2/2014TMC2034 Database Concept and Design34