MIS 385/MBA 664 Systems Implementation with DBMS/ Database Management Dave Salisbury [email protected]

(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 Business Operations CIM Customers & Suppliers External Events EDI External database access Data validation and retention Integrated data warehouse Access analysis & presentation Tools Information delivery system Decision makers Customers, Suppliers

A more sophisticated example...

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 vs. Bottom-Up  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

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

Systems Development Life Cycle

Project Identification & Selection Project Initiation & Planning Analysis Logical Design Physical Design Implementation Maintenance

Database SDLC

SDLC

Identify Project Initiate and Plan Analyze Logical Design Physical Design Implementation Maintenance

Database Development Activities

Enterprise Modeling Conceptual Data Modeling Logical DB Design Physical DB Design/Creation DB Implementation DB 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

Business Function-to-Data Entity Planning Matrix

Information System-to-Objective Planning Matrix

Functional Decomposition

Enterprise Data Modeling  The first step in database development, in which the scope and general contents of organizational databases are specified.

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 communication tool  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 Enterprise Modeling Conceptual Data Modeling Logical DB Design Physical DB Design/Creation DB Implementation DB Maintenance

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

3-schema architecture

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

3-schema development process

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

RAD

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 request for change Evaluate system cutover time box

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”

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