DATABASE DEVELOPMENT PROCESS Information Systems Planning –Information Systems ArchitectureInformation Systems Architecture –Information Engineering MethodologyInformation Engineering Methodology –Information Systems PlanningInformation Systems Planning Database Development Process –Prototyping for DB Development ProcessPrototyping for DB Development Process –An Example of Prototyping a DB ApplicationAn Example of Prototyping a DB Application –Database and IS Development ProcessDatabase and IS Development Process Three Schema Architecture for DB Development Three-Tiered Client/Server DB Architecture

Information Systems Architecture Data (Enterprise Data Model – simplified ER Diagram) Processes, which manipulate data (represented by data flow diagrams, object-models,.. ) Data Network, which transports data around the organization and.. ) People Events and Points in Time, when processes are performed (shown by state-transition diagrams and..) Reasons, for events and rules that govern the processing of data..

Information Engineering A data-oriented methodology to create and maintain information systems Top-down planning approach Four steps: –Planning - results in an Information Systems ArchitecturePlanning –Analysis - results in functional specifications…i.e. what we want –Design - results in design specifications…i.e. how we’ll do it –Implementation - results in final operational system

Information Systems Planning Align IT with the business strategies Identify strategic planning factors –Organization goalsgoals –Critical success factorsCritical success factors –Problem areasProblem areas Identify corporate planning objects –Organizational units –Organizational locations –Business functionsBusiness functions –Entity typesEntity types –application systemsapplication systems Develop enterprise model –Functional decomposition of business functionsFunctional decomposition –Enterprise data modelEnterprise data model –Planning matricesPlanning matrices

Example Results in IE Planning Phase Goals - what we hope to accomplish –Maintain 10% per year growth rate –Maintain 15% before-tax return on investment –Avoid employee layouts –Be a responsible corporate citizen Critical success factors - what must work in order to survive –High-quality products –On-time deliveries of finished products –High productivity of employees Problem areas - weaknesses we now have –Inaccurate sales forecasts –Increasing competition –Stockouts of finished products

Example of Corporate Planning Objects Organizational units Organizational locations Business functions –Business planning –Product development –Materials management –Marketing and sales Order fulfillment Order shipment –Production operations –Finance and accounting Entity types –Customer, Product, Raw Material, Order, Invoice, Employee, Equipment, Work Center Information systems –TPS: Order tracking, Order processing, Plant scheduling, Payroll –MIS: Sales management, Inventory control, Production scheduling

Example of process decomposition of an order fulfillment function Decomposition -- breaking large tasks into smaller tasks in a hierarchical structure chart

Enterprise Data Model Sets the range and general contents of organizational databases. Results in a total picture or explanation of organizational data, not in the design for a particular database. Entity-relationship diagram Descriptions of entity types Relationships between entitiesRelationships Business rules

Figure 2-1 Segment from enterprise data model (Pine Valley Furniture Company) Enterprise data model describes the entities in an organization & the relationship between these entities

Planning Matrices Function to data entity Location to function Unit to function IS application to data entity Supporting function to data entity –which data are captured, used, updated, deleted within each function IS application to business objective

Example function-to-data entry matrix Business PlanningX X X X Product Development X X X X Materials Management X X X X X X Order FulfillmentX X X X X X X X X Order ShipmentX X X X X X Sales SummarizationX X X X X Production Operations X X X X X X X Finance and AccountingX X X X X X X X Customer Product Raw Material Order Work Center Work Order Invoice Equipment Employee Business Function Data Entity Types

Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design

Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design Purpose --preliminary understanding Deliverable –request for project Database activity – enterprise modeling

Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design Purpose – state business situation and solution Deliverable – request for analysis Database activity – conceptual data modeling

Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design Purpose –thorough analysis Deliverable – functional system specifications Database activity – conceptual data modeling

Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design Purpose –information requirements structure Deliverable – detailed design specifications Database activity – logical database design

Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design Purpose –develop technology specs Deliverable – program/data structures, technology purchases, organization redesigns Database activity – physical database design

Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design Purpose –programming, testing, training, installation, documenting Deliverable – operational programs, documentation, training materials Database activity – database implementation

Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design Purpose –monitor, repair, enhance Deliverable – periodic audits Database activity – database maintenance

Database development activities during SDLC Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design Enterprise modeling Conceptual data modeling Logical db design Physical db design DB implementation DB maintenance

Database development activities: Enterprise Modeling Analyze current data processing Analyze the general business functions and their database needs Justify need for new data and databases in support of business

Database development activities: Conceptual Data Modeling Identify scope of db requirements for proposed IS Analyze overall data requirements for business functions supported by db Develop preliminary conceptual data model, including entities and relationships Compare preliminary conceptual data model with enterprise data model Develop detailed conceptual data model, including all entities, relationships, attributes, and business rules Make conceptual data model consistent with other models of IS Populate repository with all conceptual db specifications

Database development activities: Logical Database Design Analyze in detail the transactions, form, displays, and inquiries (db views) required by the business functions supported by the db Integrate db views into conceptual data model Identify data integrity and security requirements, and populate repository

Database development activities: Physical Database Design and Creation Define db to DBMS (often generated from repository) Decide on physical organization of data Design db processing programs

Database development activities: Database Implementation Code and test db processing programs Complete db documentation and training materials Install db and convert data from prior systems

Database development activities: Database Maintenance Analyze db and db applications to ensure that evolving information requirements are met Tune db for improved performance Fix errors in db and db applications and recover db when it is contaminated

Figure 2-6 The prototyping methodology and database development process

The prototyping methodology and database development process

Alternative Approaches to Database and IS Development SDLC –System Development Life cycle –Detailed, well-planned development process –Time-consuming, but comprehensive –Long development cycle Prototyping –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.

Three-schema database architecture

Database Schema Physical Schema –Physical structures – covered in chapters 5 and 6 Conceptual Schema –ER models – covered in chapters 3 and 4 External Schema –User Views –Subsets of Conceptual Schema –Can be determined from business-function/data entity matrices –DBA determines schema for different users –This is part of people-management in databases

Figure 2-8 Three-schema database architecture External schema Different people have different views of the database…these are the external schema Internal schema

Process of developing three-schema architecture for a database project

Three Schema Architecture for DB Development Conceptual Schema –Analysis project phase External Schema –Analysis and Logical Design phases –(subset of conceptual schema) Internal Schema –Physical Design phase

Three-tiered client/server database architecture

Gantt Chart Shows time estimates of tasks

PERT chart Shows dependencies between tasks

Database and IS Development Process Sources –Information systems planning –User application requests - bottom-up IS Development Approaches –Systems Development Life Cycle (SDLC) –Rapid Application Development (RAD) Prototyping CASE –Database drawing tools –Code generation (SQL) –Repository People

People in Database Development Systems analysts Database analysts Users Programmers Database and data administrators Systems programmers, network administrators, testers, technical writers

Figure 2-11 Preliminary data model for product line marketing support system

Figure 2-12 Definition of PRODUCT LINE table

Figure 2-13 Definition of PRODUCT table

Figure 2-14 Definition of ORDER table

Figure 2-15 Definition of ORDERED PRODUCT table

Figure 2-16 Database definition for Home Office product line marketing support system

Figure 2-17 Home Office sales-to-goal comparison query

Figure 2-18 Home Office product line sales comparison

Pine Valley Furniture Preliminary data model (figure 2-11)

Pine Valley Furniture MS Access data model prototype (figure 2-14)