Inf 202 Introduction to Data and Databases (Spring 2011)

Transcription

1 Inf 202 Introduction to Data and Databases (Spring 2011) Jagdish S. Gangolly Informatics CCI SUNY Albany January 25, 2011

2 Database Environment & Development Process Terminology (Data, Metadata, Database, Information, DBMS, Data model, Entity, Relation, Relationship, Attribute, Table, Field, Database application, Enterprise Resource Planning (ERP), Systems Development Life Cycle (SDLC), Prototyping, Schema (Conceptual, Logical, Physical), Data warehouse Conventional file processing system (flat file) v. Database system, their advantages and disadvantages Database environment components People: Database designers, implementors, users, administrators

3 Database Terminology Data Facts about objects you would like to keep track of Example: Joe, a STUDENT who has senior standing and a major in history, is enrolled in Inf 202 for 3 credits Metadata Data about data Example: standing can take one of these values {freshman}, {sophomore}, {junior}, {senior}; credits can take integer values between 1 and 4... Database A repository where data is organised Example: A customer database, genome database, Crime database,... Information Data that has been processed to make it useful for decisions Example: Number of history majors in Inf 202 who are seniors

4 Database Terminology DBMS Database Management System, a software system for the management of the database. Consists of programs that maintain the data as well as metadata Example: Oracle, DB2, Sybase, ldots Entity A person, organisation, or object about which data is stored in the database. In databases, entity is a set concept Example: Set of Customers, set of orders, set of products, ldots Attribute A characteristic or property of an entity Example: standing and major are attributes of a student; credits is an attribute of a course. lationship Relationship that exists between one or more entities Example: enrollment is a relationship between entities COURSE and STUDENT

5 Database Terminology atamodel Conceptualisation of the design of a database. A blueprint for the database Example: Entity Relationship Diagram (ERD) is a popular data model The remaining terms will be covered as we go along

6 File-oriented vs. Database Systems In the traditional file-oriented systems, there is a dependency relationship between programs and data. This leads to data redundancy, lack of sharing of data and consequently lack of consistency of data. Databases, on the other hand, lead to Improved data consistency Increased data sharing Reduced (and planned) data redundancy Data independence due to which costs of application development and program maintenance are reduced, leading to increased productivity.

7 Database Environment & Development Process Figure: c Pearson Education,2011

8 File-oriented vs. Database Systems Database systems also impose costs Specialised personnel (data architects, database developers, database administrators, ldots) High hardware and software costs High cost of migration to database systems High costs of maintenance (backup and recovery) Need for consensus on definitions of data

9 Database Environments Personal Databases Two-tier Client-Derver Databases Multi-tier Client-Server Databases

10 Figure: Client-Server Database with Local Area Network c Pearson Education,2011

11 Database Environment & Development Process Figure: Three-tier Client-Server Database Architecture c Pearson Education,2011

12 Systems Development Life Cycle (SDLC) Figure: Systems Development Life Cycle (SDLC) c Pearson Education,2011

13 Prototyping Figure: Systems Development Life Cycle (SDLC) c Pearson Education,2011