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DB Development Process

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DB Development Process

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    1. DB Development Process BEDU 496, Records Administration Using Database Jan. 23, 2006 Dr. Jae Park, jae.park@emich.edu STS, Eastern Michigan University

    2. © Jae H. Park 2006 2 Entity, Relationship, Attribute - Definition Entity Anything (such as a person, place, thing, or event) about which data are to be collected and stored Could be physical objects (customer, product, student, etc.) or abstraction (enrollment, flight route, order, etc.) Relationship Association among (two or more) entities Cardinality: One-to-one, one-to-many, many-to-many relationships Attributes Characteristics of an entity Student’s (entity) attributes: student ID, student name, address, etc.

    3. © Jae H. Park 2006 3 Three Schema components External Schema (views) How users see the data Conceptual schema Defines logical structure of data using E-R or other notation (independent from data management technology) Internal schema Logical schema Representation of data for a type of data management technology Physical schema Describes files and indexes used

    4. © Jae H. Park 2006 4 DB Development DB is a part of an information system DB development is a part of information systems development process Therefore, DB has to be developed in coordination with other development activities of information system

    5. © Jae H. Park 2006 5 Systems Development Life Cycle (SDLC) Traditional methodology used to develop, maintain, and replace information systems also known as a cascade or waterfall model each step follows into the next Steps overlap in time, thus can be conducted in parallel Possible to backtrack to previous steps if necessary

    6. © Jae H. Park 2006 6 Systems Development Life Cycle (SDLC)

    7. © Jae H. Park 2006 7 SDLC Project Identification and Selection To develop a preliminary understanding of the business situation that has caused the request for a new or an enhanced information system To deliver a formal request to conduct a project to design and develop an information systems solution to the business problems or opportunities Project Initiation and Planning To state business situation and how information systems might help solve a problem or make an opportunity possible To deliver a written request to study the possible changes to an existing system or the development of a new system

    8. © Jae H. Park 2006 8 SDLC Analysis To analyze the business situation thoroughly to determine requirements, to structure those requirements, and to select among competing system features To deliver the functional specifications for a system that meets user requirements and is feasible to develop and implement Logical Design To elicit and structure all information requirements To deliver detailed functional specifications of all data, forms, reports, displays, and processing rules

    9. © Jae H. Park 2006 9 SDLC Physical Design To develop all technology and organizational specifications To deliver program and database structures, technology purchases, physical site plan, and organizational redesigns Implementation To write programs, build data files, test and install the new system, train users, and finalize documentation To deliver programs that work accurately and to specifications, documentation, and training materials

    10. © Jae H. Park 2006 10 SDLC Maintenance To monitor the operation and usefulness of a system, and to repair and enhance the system To deliver periodic audits of the system to demonstrate whether the system is accurate and still meets needs

    11. © Jae H. Park 2006 11 DB development in SDLC Enterprise Modeling

    12. © Jae H. Park 2006 12 Enterprise Modeling The beginning step of database development process Analyze current data processing Analyze the general business functions and their database needs Justify need for new data and databases in support of business

    13. © Jae H. Park 2006 13 A Segment of Enterprise Data Model in diagram

    14. © Jae H. Park 2006 14 Conceptual Data Modeling Identify scope of database requirements for proposed information system Analyze overall data requirements for business functions supported by database 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 information system Populate repository with all conceptual database specifications Top-down analysis

    15. © Jae H. Park 2006 15 Preliminary Conceptual Data Model (Chen ERD)

    16. © Jae H. Park 2006 16 Detailed Conceptual Data Model (Chen ERD)

    17. © Jae H. Park 2006 17 Detailed Conceptual Data Model (Crow’s ERD)

    18. © Jae H. Park 2006 18 Logical Database Design Analyze in detail the transactions, forms, displays, and inquiries (database views) required by the business functions supported by the database Integrate database views into conceptual data model Identify data integrity and security requirements and populate repository Bottom-up analysis

    19. © Jae H. Park 2006 19 Physical Database Design and definition Define database to DBMS Decide on physical organization of data Design database processing programs

    20. © Jae H. Park 2006 20 Database Implementation Code and test database processing programs Complete database documentation and training materials Install database and convert data from prior systems

    21. © Jae H. Park 2006 21 Database Maintenance Analyze database and database applications to ensure that evolving information requirements are met Tune database for improved performance Fix errors in database and database applications and recover database when it is contaminated

    22. © Jae H. Park 2006 22 Prototyping One of the most popular Rapid Application development (RAD) methods An iterative process of systems development in which requirements are converted to a working system that is continually revised through close work between analysts and users Improved development time

    23. © Jae H. Park 2006 23 Prototyping and DB development

    24. © Jae H. Park 2006 24 CASE Computer-Aided Software Engineering tools Software that provide automated support for some portion of the system development process main features Ability to help users draw (database intelligent) data models using entity-relationship and other notations Ability to generate code (e.g., database definition commands, SQL commands, C or other language commands, etc) Ability to integrate drawings and codes to store in repository

    25. © Jae H. Park 2006 25 Business Rules A statement that defines or constraints some aspect of the business In a form of natural language, a structured data model, or other information systems documentation E.g., A student may register for a section of a course only if he or she has successfully completed the prerequisites for that course A preferred customer qualifies for a 10 percent discount, unless he has an overdue account balance A student must have one faculty advisor A student is any person who has applied for an admission or taken a course or training program from any credit or non-credit unit of the university Documenting rules and policies of an organization that govern data is what data modeling is all about In database, data about each student will be associated with data about some faculty advisor

    26. © Jae H. Park 2006 26 Gathering Business Rules Gather description of business functions, events, policies, units, stakeholders, etc. can be found in interview notes, organization documents (personnel manual, policies, contracts, marketing brochures, and tech instructions) and other sources. Who, when, where, what, why, and how of the organization

    27. © Jae H. Park 2006 27 Data Names and Definitions Data objects are must be named and defined before they can be used unambiguously in a model of organizational data In E-R model, we have to give entity, relationship, and attributes clear and distinct names and definitions Definition does not have to be provided to common terms such as ‘day’, ‘month’, ‘television’, etc.

    28. © Jae H. Park 2006 28 Naming Guidelines Relate to business not technical characteristics Customer, faculty, but not file1, bit2, … Be meaningful Avoid to use person, it, has, is, … Be unique Home_address vs. Campus_address Readable Composed of words taken from approved list Maximum not ceiling, upper limit Repeatable Student_ID, Faculty_ID

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