Chapter 2 The Database Development Process Modern Database
Chapter 2: The Database Development Process Modern Database Management 7 th Edition Jeffrey A. Hoffer, Mary B. Prescott, Fred R. Mc. Fadden © 2005 by Prentice Hall 1
Objectives n n n n Definition of terms Describe system development life cycle Explain prototyping approach Explain roles of individuals Explain three-schema approach Explain role of packaged data models Explain three-tiered architectures Draw simple data models Chapter 2 © 2005 by Prentice Hall 2
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 © 2005 by Prentice Hall 3
Figure 2 -1 Segment from enterprise data model (Pine Valley Furniture Company) [simplified E-R diagram, repeat of figure 1. 3] Enterprise data model describes the high-level entities in an organization and the relationship between these entities Chapter 2 © 2005 by Prentice Hall 4
Information Systems Architecture (ISA) n n Conceptual blueprint for organization’s desired information systems structure Consists of: n n n Data (e. g. Enterprise Data Model – simplified ER Diagram) Processes – data flow diagrams, process decomposition, etc. Data Network – topology diagram (like fig 1. 9) People – people management using project management tools (Gantt charts, etc. ) Events and points in time (when processes are performed) Reasons for events and rules (e. g. decision tables) Chapter 2 © 2005 by Prentice Hall 5
Information Engineering n n n A data-oriented methodology to create and maintain information systems Top-down planning: a generic IS planning methodology for obtaining a broad understanding of the IS needed by the entire organization Four steps to Top-Down planning: n n Planning Analysis Design Implementation Chapter 2 © 2005 by Prentice Hall 6
Information Systems Planning (Table 2 -1) n n Purpose: align information technology with organization’s business strategies Three steps: 1. 2. 3. Identify strategic planning factors Identify corporate planning objects Develop enterprise model Chapter 2 © 2005 by Prentice Hall 7
Identify Strategic Planning Factors (Table 2 -2) n n n Organization goals – what we hope to accomplish Critical success factors – what MUST work in order for us to survive Problem areas – weaknesses we now have Chapter 2 © 2005 by Prentice Hall 8
Identify Corporate Planning Objects (Table 2 -3) n n n Organizational units – departments Organizational locations Business functions – groups of business processes Entity types – the things we are trying to model for the database Information systems – application programs Chapter 2 © 2005 by Prentice Hall 9
Develop Enterprise Model n Functional decomposition n See n Enterprise data model n See n Figure 2 -2 Figure 2 -1 Planning matrixes n See Chapter 2 Figure 2 -3 © 2005 by Prentice Hall 10
Figure 2 -2 -- Example of process decomposition of an order fulfillment function (Pine Valley Furniture) Decomposition -- breaking large tasks into smaller tasks in a hierarchical structure chart Chapter 2 © 2005 by Prentice Hall 11
Planning Matrixes n n Describe relationships between planning objects in the organization Types of matrixes: Function-to-data entity n Location-to-function n Unit-to-function n IS-to-data entity n Supporting function-to-data entity n IS-to-business objective n Chapter 2 © 2005 by Prentice Hall 12
Data Entity Types Business Function (users) Business Planning Product Development Materials Management Order Fulfillment Order Shipment Sales Summarization Production Operations Finance and Accounting Chapter 2 Customer Product Raw Material Order Work Center Work Order Invoice Equipment Employee Example business function-todata entity matrix (Fig. 2 -3) X X X X X X X X X X X X X © 2005 by Prentice Hall 13
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 © 2005 by Prentice Hall 14
Systems Development Life Cycle (Figures 2 -4, 2 -5) Project Identification and Selection Project Initiation and Planning Analysis Logical Design Physical Design Implementation Maintenance Chapter 2 © 2005 by Prentice Hall 15
Systems Development Life Cycle (cont. ) (Figures 2 -4, 2 -5) Project Identification and Selection Purpose --preliminary understanding Deliverable –request for project Project Initiation and Planning Analysis Logical Design Physical Design Database activity – enterprise modeling Implementation Maintenance Chapter 2 © 2005 by Prentice Hall 16
Systems Development Life Cycle (cont. ) (figures 2 -4, 2 -5) Project Identification and Selection Purpose – state business situation and solution Deliverable – request for analysis Project Initiation and Planning Analysis Logical Design Physical Design Database activity – conceptual data modeling Implementation Maintenance Chapter 2 © 2005 by Prentice Hall 17
Systems Development Life Cycle (cont. ) (figures 2 -4, 2 -5) Project Identification and Selection Purpose – thorough analysis Deliverable – functional system specifications Project Initiation and Planning Analysis Logical Design Physical Design Database activity – conceptual data modeling Implementation Maintenance Chapter 2 © 2005 by Prentice Hall 18
Systems Development Life Cycle (cont. ) (figures 2 -4, 2 -5) Project Identification and Selection Purpose – information requirements structure Deliverable – detailed design specifications Project Initiation and Planning Analysis Logical Design Physical Design Database activity – logical database design Implementation Maintenance Chapter 2 © 2005 by Prentice Hall 19
Systems Development Life Cycle (cont. ) (figures 2 -4, 2 -5) Purpose – develop technology specs Deliverable – program/data structures, technology purchases, organization redesigns Project Identification and Selection Project Initiation and Planning Analysis Logical Design Physical Design Database activity – physical database design Implementation Maintenance Chapter 2 © 2005 by Prentice Hall 20
Systems Development Life Cycle (cont. ) (figures 2 -4, 2 -5) Purpose – programming, testing, training, installation, documenting Deliverable – operational programs, documentation, training materials Project Identification and Selection Project Initiation and Planning Analysis Logical Design Physical Design Database activity – database implementation Implementation Maintenance Chapter 2 © 2005 by Prentice Hall 21
Systems Development Life Cycle (cont. ) (figures 2 -4, 2 -5) Project Identification and Selection Purpose – monitor, repair, enhance Deliverable – periodic audits Project Initiation and Planning Analysis Logical Design Physical Design Database activity – database maintenance Implementation Maintenance Chapter 2 © 2005 by Prentice Hall 22
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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 © 2005 by Prentice Hall 28
CASE n n Computer-Aided Software Engineering (CASE) – software tools providing automated support for systems development Three database features: Data modeling – entity-relationship diagrams n Code generation – SQL code for table creation n Repositories – knowledge base of enterprise information n Chapter 2 © 2005 by Prentice Hall 29
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 rejustification after each phase Chapter 2 © 2005 by Prentice Hall 30
Managing Projects: People Involved n n n Systems analysts Database analysts Users Programmers Database/data administrators Systems programmers, network administrators, testers, technical writers Chapter 2 © 2005 by Prentice Hall 31
Figure 2 -8 a Gantt Chart Shows time estimates of tasks Chapter 2 © 2005 by Prentice Hall 32
Figure 2 -8 b PERT chart Chapter 2 Shows dependencies between tasks © 2005 by Prentice Hall 33
Database Schema n Physical Schema n n Conceptual Schema n n Physical structures – covered in chapters 5 and 6 E-R models – covered in chapters 3 and 4 External Schema n n User Views Subsets of Conceptual Schema Can be determined from business-function/data entity matrices DBA determines schema for different users Chapter 2 © 2005 by Prentice Hall 34
Different people have different views of the database…these are the external schema The internal schema is the underlying design and implementation Chapter 2 © 2005 by Prentice Hall 35
Figure 2 -11 Three-tiered client/server database architecture Chapter 2 © 2005 by Prentice Hall 36
Pine Valley Furniture Preliminary data model (Figure 2 -12) Chapter 2 © 2005 by Prentice Hall 37
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