Information Resources Management January 23, 2001

Agenda n Administrivia n Development Methodologies n People Involved n Schema Architecture n CASE Tools n Homework #2

Administrivia n Homework #1 n Book? n Web Page n Registration

Development Methodologies n Information Engineering n Waterfall Model n RAD Model n Phased (Incremental) n Prototyping n Spiral n Customization

Information Engineering n Data-oriented n Top-down approach n Broad understanding first n Then, specific systems identified n Information systems related to business objectives

Information Engineering Steps n Planning n Analysis n Design n Implementation

Info. Eng. Planning Phase n Identify strategic planning factors n goals, CSFs, problems n Identify corporate planning objectives n units, locations, functions, types n Develop enterprise model n functions, data, relationships

Waterfall Model (SDLC) n System Developmen Lifecycle n Linear and sequential n “Classical” n Specific, predefined phases n Definite end points for each n Historically, most widely used n Template for other models

Waterfall SDLC n Single system development n Information Engineering or other approach for overall strategic systems planning

Waterfall Model Time Initiation Analysis Logical Design Physical Design Implement Maintain Identification

Database Lifecycle 1. Enterprise Modeling 2. Conceptual Data Modeling 3. Logical Database Design 4. Physical Database Design and Creation 5. Database Implementation 6. Database Maintenance

Waterfall Model Time Initiation Analysis Logical Design Physical Design Implement Maintain Identification Enterprise Modeling Conceptual Data Modeling Logical Data Modeling Physical Database Design and Creation Database Implementation Database Maintenance

Waterfall Problems n Projects aren’t so sequential n Requirements finalized early n Delay before system delivered n All or nothing n Sequential dependencies create delays forcing others to wait

RAD Model n Rapid Application Development n Complete Development Approach n “RAD/FAST” or “JAD” Session n “Components” n Fully functional and useful n Completely specified, built and installed in days n Concurrent

RAD Model Business Modeling Data Modeling Process Modeling Application Generation Testing & Turnover Business Modeling Data Modeling Process Modeling Application Generation Testing & Turnover Business Modeling Data Modeling Process Modeling Application Generation Testing & Turnover Team 1 Team 2 Team 3 Time

RAD Drawbacks n System requires proper “components” n Resources & skills for large number of teams n High level of user involvement and commitment required n System performance may suffer n Technical risks dramatically increase project risks

Phased (Incremental) Model n System is delivered in “increments” n Initial increment is “core product” n Increments larger than RAD system pieces n Focus on specific increment - delay decisions on future increments n System revised as development progresses n Sequential

Incremental Model AnalysisDesignCodeTest AnalysisDesignCodeTest AnalysisDesignCodeTest Deliver #1 Deliver #2 Deliver #3

Incremental Drawbacks n System must have “increments” n Increments must be useful to users n Overall, longer (much longer) development time n Business procedure changes with each increment delivered

Prototyping Model n Geared toward requirement collection, unfamiliar technology, complex interface design n Prototype is a way of managing risk as much as an exploration of new ideas Listen to Customer Build/ Revise Customer Test Drive

Prototyping n Prototype: software model of system n Closed-Ended - throwaway n Open-Ended - evolutionary n Explorative - identify requirements n Experimental - try options n “Entire” System n Key elements only

Prototyping Cycle n Time between prototypes n Influences number of prototypes n Shorter time between - more prototypes n More prototypes (generally) better product n Company standard of fixed number of prototypes

Candidates for Prototyping n Dynamic visual displays n Heavy user interaction n Complex algorithms or calculations n Ambiguous or conflicting requirements

Prototyping Considerations n User Resources n Decision Makers n IS Resources - Tools, People n User Understanding of Prototype n Time to completion n Full functionality n Performance requirements n Closed-ended n “Paper Prototype”

Spiral Model n Evolutionary software development n Task Regions n Predefined tasks in each n Multiple passes n Around the spiral n Through each region n Increasing complexity and level of detail n Prototyping usually involved

Spiral Model

Spiral Drawbacks n Unfamiliarity - newer model n Developer training n User training n High user involvement n When do spirals end? n Management and control very important n Risk assessment is critical n Expertise is needed

Methodology Customization n Fit the structure of the solution to the structure of the problem n Don’t use a hammer to drive in a screw n Customize based on system size or complexity, development risk, staff and tool availability, user experience, controls required and system risk n Customize a single approach n Combine multiple approaches

People Involved n Project manager n Systems analysts & designers n Database analysts & designers n Users n Programmers n Database Administrators (DBAs) n Networking experts n Other technical experts

Project Manager n Assemble project team n Build detailed project plans n Monitor people and plan n Work with other management n Ultimately held responsible for success of system development project

System Analysts & Designers n Focus on business needs n “Bridge” business and technology n System functions and data n Analyst - “What should be done?” n Designer - “How should it be done?” n Greater technology focus

Database Analysts and Designers n Focus on business needs n “Bridge” business and technology n Primary focus on data requirements n Analyst - “What data is needed?” n Designer - “How should it be stored?”

Users n Ultimate users of new system n Provide requirements, business needs n Review documentation n Test & accept new system n Train other users n May represent “actual” users

Programmers n Design programs (detailed design) n “Write” programs n Test programs n Write SQL for database access

Database Administrators n Ultimately responsible for databases n current and future n Provide data and modeling expertise n Provide DBMS expertise n Monitor and tune databases

Other Technical Experts n Provide expertise in specified areas n networking n operating systems n hardware n development languages n development methodologies and tools

Database Schema Architecture n Schema - view or model of a database n Different views of same database n Three kinds of schemas n Conceptual n External n Physical

Conceptual Schema n Logical model of database n Data model n Entity-Relationship Diagram n Independent of DBMS n Focus on data and relationships

External Schema n Also, User View n Subset of conceptual schema n data for specific task n specific users n specifc programs n Independent of DBMS n Entity-Relationship Diagram

Physical Schema n Description of how data will actually be stored n Structure n Data types n Based on conceptual schema n Specific process for conversion n Tied to specific DBMS

Schema Relationships Physical Schema Conceptual Schema External Schema 1 External Schema 2 External Schema n

Schema Development Physical Schema Conceptual Schema External Schemas Enterprise Modeling Conceptual Data Modeling Logical Database Design Physical Database Design Database Implementation & Maintenance

CASE Tools n Computer-Aided Software Engineering n Computer-Automated? n Features n Types n Repository n Tools

CASE Features n Diagrams n Documentation n Data Dictionary n Team Coordination n Prototyping n Code Generation n Reverse Engineering

CASE Types n Full development - integrated n iCASE n Analysis & Design n upper CASE n Implementation & Maintenance n lower CASE

CASE Repository n Data dictionary - data element definitions and descriptions n Ensures consistency n Repository is much more n Database with linkages for all system development products and activities n Integration n Even across different CASE tools

CASE Tools n Visio Microsoft n on laptops n Visible Analyst - Visible Systems n ER/Studio - Embarcadero n ERWin - Computer Associates n Oracle Designer - Oracle n Power Designer - Sybase

Homework #2 n Database Jobs n Search any source; find 5 jobs n Review requirements n Find your job & review n Table of results n Analyze number and type of jobs and the knowledge needed