Chapter 2 The Database Development Process Modern Database

Enterprise Data Model n n n n First step in database development Specifies scope and general content Overall picture of organizational data at high level of abstraction Entity-relationship diagram Descriptions of entity types Relationships between entities Business rules Chapter 2 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 2

Segment from enterprise data model Enterprise data model describes the highlevel entities in an organization and the relationship between these entities Chapter 2 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 3

Two Approaches to Database and IS Development n SDLC n n n System Development Life Cycle Detailed, well-planned development process Time-consuming, but comprehensive Long development cycle Prototyping n n Rapid application development (RAD) Cursory attempt at conceptual data modeling Define database during development of initial prototype Repeat implementation and maintenance activities with new prototype versions Chapter 2 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 4

Systems Development Life Cycle Planning Analysis Logical Design Physical Design Implementation Maintenance Chapter 2

Systems Development Life Cycle (cont. ) Purpose–preliminary understanding Deliverable–request for study Planning Analysis Logical Design Physical Design Database activity– enterprise modeling and early conceptual data modeling Chapter 2 Implementation Maintenance © 2009 Pearson Education, Inc. Publishing as Prentice Hall 6

Systems Development Life Cycle (cont. ) Purpose–thorough requirements analysis and structuring Deliverable–functional system specifications Planning Analysis Logical Design Physical Design Database activity–thorough and integrated conceptual data modeling Chapter 2 Implementation Maintenance © 2009 Pearson Education, Inc. Publishing as Prentice Hall 7

Systems Development Life Cycle (cont. ) Purpose–information requirements elicitation and structure Deliverable–detailed design specifications Planning Analysis Logical Design Physical Design Database activity– logical database design (transactions, forms, displays, views, data integrity and security) Chapter 2 Implementation Maintenance © 2009 Pearson Education, Inc. Publishing as Prentice Hall 8

Systems Development Life Cycle (cont. ) Purpose–develop technology and organizational specifications Deliverable–program/data structures, technology purchases, organization redesigns Planning Analysis Logical Design Physical Design Database activity– physical database design (define database to DBMS, physical data organization, database processing programs) Chapter 2 Implementation Maintenance © 2009 Pearson Education, Inc. Publishing as Prentice Hall 9

Systems Development Life Cycle (cont. ) Planning Analysis Purpose–programming, testing, training, installation, documenting Deliverable–operational programs, documentation, training materials Logical Design Physical Design Database activity– database implementation, including coded programs, documentation, installation and conversion Chapter 2 Implementation Maintenance © 2009 Pearson Education, Inc. Publishing as Prentice Hall 10

Systems Development Life Cycle Purpose–monitor, repair, enhance Deliverable–periodic audits Planning Analysis Logical Design Physical Design Database activity– database maintenance, performance analysis and tuning, error corrections Chapter 2 Implementation Maintenance © 2009 Pearson Education, Inc. Publishing as Prentice Hall 11

Prototyping Database Methodology Chapter 2 © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Prototyping Database Methodology (cont. ) Chapter 2 © 2009 Pearson Education, Inc. Publishing as

Packaged Data Models n n Model components that can be purchased, customized, and assembled into full-scale data models Advantages n n n Reduced development time Higher model quality and reliability Two types: n n Universal data models Industry-specific data models Chapter 2 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 17

Managing Projects n n Project–a planned undertaking of related activities to reach an objective that has a beginning and an end Involves use of review points for: Validation of satisfactory progress n Step back from detail to overall view n Renew commitment of stakeholders n n Incremental commitment–review of systems development project after each development phase with re justification after each phase Chapter 2 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 18

Managing Projects: People Involved n n n n n Chapter 2 Business analysts Systems analysts Database analysts and data modelers Users Programmers Database architects Data administrators Project managers Other technical experts © 2009 Pearson Education, Inc. Publishing as Prentice Hall 19

Database Schema • • • Internal level: describes how data is stored. The way perceived by the DBMS & OS. Conceptual level: describes what data stored in DB, and the relationships among the data. The way perceived by the DBA & programmers. External level: describes the part of the DB that user is interested in. The way perceived by the end users. Database Systems: A Practical Approach to Design, Implementation and Management, by T. Connolly and C. Begg. 20

Three-schema architecture Different people have different views of the database…these are the external schema The internal schema is the underlying design and implementation Chapter 2 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 21

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