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MIS 385/MBA 664 Systems Implementation with DBMS/ Database Management. Dave Salisbury salisbury@udayton.edu (email) http://www.davesalisbury.com/ (web site). Information Systems Architecture.
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MIS 385/MBA 664Systems Implementation with DBMS/Database Management Dave Salisbury salisbury@udayton.edu (email) http://www.davesalisbury.com/ (web site)
Information Systems Architecture • A conceptual blueprint or plan that expresses the desired future structure for the information systems in an organization.
Architecture example CIM Data validation and retention Integrated data warehouse Access analysis & presentation Tools Information delivery system Business Operations EDI Customers & Suppliers External database access External Events Decision makers Customers, Suppliers
Information Systems Architecture • Key Components: • data • processes which manipulate data • network which transports data • people who perform processes and send and receive data • events and points in time when processes are performed • reasons for events and rules which govern data processing
Information Engineering • An Information Systems Architecture is developed by IS planners following a particular methodology such as Information Engineering.
Information Engineering • Data-oriented methodology • Uses top-down planning in which specific information systems are deduced from a broad understanding of organization’s information needs, rather than relying on specific user information requests • Offers perspective on relationship of information systems to business objectives
Top-Down Planning: A methodology that attempts to gain a broad understanding of the information system needs of the entire organization Bottom-Up Planning: A methodology that identifies and defines IS development projects based upon solving operational business problems or taking advantage of business opportunities Top-Down vs. Bottom-Up
Information engineering • Information systems planning • Identify strategic planning factors (goals, CSFs, problem areas) • IT vision • Identify corporate planning objectives • Information system architecture • Develop enterprise model • Systems analysis • Systems design • Implementation
Project Identification & Selection Project Initiation & Planning Analysis Logical Design Physical Design Implementation Maintenance Systems Development Life Cycle
Database SDLC SDLC Database DevelopmentActivities Identify Project Enterprise Modeling Initiate and Plan Conceptual Data Modeling Analyze Logical DB Design Logical Design Physical DB Design/Creation Physical Design DB Implementation Implementation DB Maintenance Maintenance
Planning Matrixes • Show interrelationships between objects. • Location-to-Function • Unit-to-Function • Information System-to-Data Entity • Supporting Function-to-Data Entity • Information System-to-Objective
Enterprise Data Modeling • The first step in database development, in which the scope and general contents of organizational databases are specified.
Enterprise Modeling Conceptual Data Modeling Logical DB Design Physical DB Design/Creation DB Implementation DB Maintenance Enterprise Data Model • A model which includes: • overall range of organizational databases • general contents of organizational databases • Built as part of IS planning for the organization and not the design of a particular database • One part of an organization’s overall information systems architecture (ISA)
Enterprise Modeling Conceptual Data Modeling Logical DB Design Physical DB Design/Creation DB Implementation DB Maintenance Conceptual Database Modeling • Determine user requirements • Determine business rules • Build conceptual data model • outcome is an entity-relationship diagram or similar communicationtool • population of repository
Enterprise Modeling Conceptual Data Modeling Logical DB Design Physical DB Design/Creation DB Implementation DB Maintenance Logical Database Design • Select logical database model • commit to a database alternative • Map Entity-Relationship Diagrams • Normalize data structures • Specify business rules
Enterprise Modeling Conceptual Data Modeling Logical DB Design Physical DB Design/Creation DB Implementation DB Maintenance Physical Database Design • Select DBMS • Select storage devices • Determine access methods • Design files and indexes • Determine database distribution • Specify update strategies
Database implementation • Code and test database processing programs • Complete documentation • Install database and convert data Enterprise Modeling Conceptual Data Modeling Logical DB Design Physical DB Design/Creation DB Implementation DB Maintenance
Database Maintenance • Analyze database and applications to ensure evolving information requirements are being met • Tune database for improved performance • Fix errors • Provide data recovery when needed Enterprise Modeling Conceptual Data Modeling Logical DB Design Physical DB Design/Creation DB Implementation DB Maintenance
Documentation • most formal development methodologies are documentation based • helps managers monitor progress and quality of project • facilitates communication between team members • includes models • various stages are not complete until documentation is accepted
Some Keys to Success... • accurate requirements definition • commitment • effective change management • manageable size • champion
Three Schema Architecture for Database Development • Conceptual Schema • Analysis project phase • External Schema • Analysis and Logical Design phases • (subset of conceptual schema) • Internal Schema • Physical Design phase
Conceptual Schema • Describes the logical structure of the entire database • Independent of a specific DBMS • Avoids details of physical design • Stated in • ERDs • metadata
External Schema • Also called a user view • Specifications include screen formats, report formats, transaction definitions
Physical Schema • Describes physical structure of entire database • Specifies how data from a conceptual schema are stored in secondary memory • Sometimes called internal schema • Specifications include physical file and data structures, storage organization, and index structures
Rapid application development (RAD) • design methodology which speeds systems delivery through a combination of speedy design iterations, data modeling, user/developer teamwork, and automated development tools. • encompasses a set of techniques that can be used to build complex, strategic, and mission-critical applications in months rather than years
The RAD lifecycle • requirements planning • conduct joint requirement planning workshop • design • conduct JAD workshop • construction • members of team monitor evolution, system is prototyped • cutover • installation
Within the time box... Requirements planning User design construction phase Build & evolve prototype User review time box request for change Evaluate system cutover
Barriers to overcome... • poor training/ tools • reluctance to leave old methods behind • mindset that RAD is not adequate for large-scale systems development • speedy delivery does not mean low quality • “scope/function creep”