Database 2 External Schema


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Database 2 External Schema

  1. 1. RECAP <ul><li>Role of Databases </li></ul><ul><li>Classification </li></ul><ul><li>Evolution of Databases </li></ul>
  2. 2. <ul><li>Aim </li></ul><ul><ul><li>General steps in Design & Development of Databases in context to information system Development process. </li></ul></ul><ul><li>Objectives </li></ul><ul><ul><li>Understand Information System Architecture </li></ul></ul><ul><ul><li>Database Analysis, Design and Implementation issues </li></ul></ul><ul><ul><li>Design Example </li></ul></ul>DATABASE DEVELOPMENT PROCESS
  3. 3. <ul><li>Database development Starts with Enterprise Data Modeling (EDM) </li></ul><ul><li>Steps in EDM </li></ul><ul><ul><li>Review current system </li></ul></ul><ul><ul><li>Analyse the business area to be supported </li></ul></ul><ul><ul><li>Data requirement </li></ul></ul><ul><ul><li>Plan DB Project (s) </li></ul></ul><ul><li>EDM considers general contents of organizational </li></ul><ul><li>databases. Overall picture </li></ul><ul><li>However, comprehensive architectural plan of IS </li></ul><ul><li>development is essential </li></ul><ul><li>Features </li></ul><ul><ul><li>ISA can grow & expand (vision) </li></ul></ul><ul><ul><li>Impact of Technology </li></ul></ul><ul><ul><li>Flexible </li></ul></ul><ul><ul><li>Eye on standards </li></ul></ul>ENTERPRISE DATA MODELING
  4. 4. <ul><li>Planning </li></ul><ul><li>Budget </li></ul><ul><li>Overall direction of IT & decision </li></ul><ul><li>Priority areas </li></ul>BENEFITS OF ISA
  5. 5. <ul><li>Data </li></ul><ul><li>Process (DFD, Models) </li></ul><ul><li>Network </li></ul><ul><li>People </li></ul><ul><li>Events & points in time (RTDB) </li></ul><ul><li>Reason for Events , Rules </li></ul>KEY COMPONENTS OF ISA
  6. 7. <ul><li>A Data oriented methodology for development of information systems. </li></ul><ul><li>For engineering IS, approach the Top-down methodology is followed where integration of individual system components takes place </li></ul>IS DEVELOPMENT
  7. 8. <ul><li>Planning : ISA, including EDM (results is an ISA) </li></ul><ul><li>Analysis : Conceptual Data Model & Logical data base </li></ul><ul><li>Design : Logical / Physical DB </li></ul><ul><li>Implementation : DB definitions , Tables, Indexes , Codes </li></ul>STEPS OF IS DEVELOPMENT
  8. 9. <ul><li>Goal : To support Business Strategies with IT </li></ul><ul><li>3 Steps </li></ul><ul><ul><li>Identify strategic planning factors – to develop planning context and to link information systems plan to the strategic plan of the organization </li></ul></ul><ul><ul><ul><li>Goals : Growth Rate, Return on Investment ( ROI )…….. </li></ul></ul></ul><ul><ul><ul><li>Success Factors : Quality, On-time, Employee productivity….. </li></ul></ul></ul><ul><ul><ul><li>Problem Areas : Competition, Maintenance of records…. </li></ul></ul></ul>IS PLANNING
  9. 10. <ul><li>2. Identify Corporate Planning objects – define the business scope </li></ul><ul><ul><ul><li>Organizational Units – Various departments </li></ul></ul></ul><ul><ul><ul><li>Locations – business places </li></ul></ul></ul><ul><ul><ul><li>Business Functions – business processes like product development </li></ul></ul></ul><ul><li>4. Entity Types : Categories of data about people, places & things managed by company </li></ul><ul><li>5. Information System : Application S/W & supporting procedures. </li></ul>IS PLANNING
  10. 11. <ul><li>3. Develop Enterprise Model – consists of a functional breakdown , an enterprise data model and various planning matrices. </li></ul><ul><li>1. Functional Decomposition – breaking down description of system into finer and finer details, identify important components. </li></ul><ul><li>2. High level ER diagram </li></ul><ul><li>3. Planning Matrices – A format for showing interrelationships between data entities. </li></ul><ul><ul><li>Functions Support Functions </li></ul></ul><ul><ul><li>Production Operation Scheduling, Fabrication, Assembly </li></ul></ul><ul><ul><li>Material Management Material requirement planning </li></ul></ul><ul><ul><li>- Purchasing </li></ul></ul><ul><ul><li>- Receiving </li></ul></ul><ul><ul><li>Marketing - Market research </li></ul></ul><ul><ul><li>- Order fulfillment </li></ul></ul><ul><ul><li>- Distribution </li></ul></ul>IS PLANNING
  11. 12. <ul><li>Develop Enterprise Model </li></ul><ul><ul><li>Decompose business function </li></ul></ul><ul><ul><li>Planning Matrixes (using ER) </li></ul></ul><ul><ul><li>Functional decomposition helps in simplify problems , identify important components. </li></ul></ul><ul><ul><li>Functions Support Functions </li></ul></ul><ul><ul><li>Production Operation Scheduling, Fabrication, Assembly </li></ul></ul><ul><ul><li>Material Management Material requirement planning </li></ul></ul><ul><ul><li>- Purchasing </li></ul></ul><ul><ul><li>- Receiving </li></ul></ul><ul><ul><li>Marketing - Market research </li></ul></ul><ul><ul><li>- Order fulfillment </li></ul></ul><ul><ul><li>- Distribution </li></ul></ul>
  12. 13. <ul><li>Sample Planning Matrix – for Order Fulfillment </li></ul><ul><ul><li>Identify 1 or more database (s) ,keeping in mind Enterprise view </li></ul></ul><ul><ul><li>Develop ER models,describe each entity,business rules </li></ul></ul><ul><ul><li>Develop planning Matrixes,linking various components </li></ul></ul>X PLANNING MATRIX Business Function Business Planning Material Manage Finance & Accts Customer Product Invoice Employee Data/Entity X X X X X X X X
  13. 14. <ul><li>Advantages </li></ul><ul><ul><li>Identify Orphans : indicate which data entities are not used by any function or which functions do not use any entities </li></ul></ul><ul><ul><li>Spot Missing Entities </li></ul></ul><ul><ul><li>Prioritize Development </li></ul></ul>PLANNING MATRIX
  14. 15. <ul><li>Types of Planning Matrices </li></ul><ul><ul><li>Location to Function : which business functions are performed at which business locations </li></ul></ul><ul><ul><li>Unit to Function : which business functions are performed at which business units </li></ul></ul><ul><ul><li>Information System to Data Entity : explains how each information system interacts with data entity </li></ul></ul><ul><ul><li>Supporting Function to Data Entity : Identified which data are captured , used , updated or deleted within each function </li></ul></ul><ul><ul><li>Information System to Objective : Shows which information system support which business objective </li></ul></ul>PLANNING MATRIX
  15. 16. Project Identification & selection Project Initiation & Planning Analysis Logical Design Physical Design Implementation Maintenance Enterprise Model Conceptual Data Model DATABASE DEVELOPMENT PROCESS Logical Data Base Design Physical Design Database Implementation Database Maintenance Database Development SDLC
  16. 17. <ul><li>In SDLC total specifications of IS is developed in pieces </li></ul><ul><li>Steps may overlap </li></ul><ul><li>Enterprise model </li></ul><ul><ul><li>Data needed for each IS, general contents of Data base </li></ul></ul><ul><li>Conceptual Data Modeling </li></ul><ul><ul><li>Entities & Relationships </li></ul></ul><ul><ul><li>Detailed Data model (Data base Analyst) </li></ul></ul><ul><ul><li>Identifying all organizational data </li></ul></ul><ul><ul><li>Business relationship </li></ul></ul><ul><ul><li>Rules for data integrity </li></ul></ul><ul><ul><li>Model may require improvements – ER,EER….. </li></ul></ul>SDLC and DBMS APPROACH
  17. 18. <ul><li>Logical Database Design </li></ul><ul><ul><li>Transform conceptual model Relations that are specific to DBMS used </li></ul></ul><ul><ul><li>Transactions, reports,displays to be supported </li></ul></ul><ul><ul><li>What data are to be maintained in DB? </li></ul></ul><ul><ul><li>Several users views to be integrated </li></ul></ul><ul><ul><li>Normalization : Process of designing well structured relations, avoid unnecessary duplication of data. </li></ul></ul><ul><li>Physical DB Design </li></ul><ul><ul><li>Identify programs to process transactions, generate reports </li></ul></ul><ul><ul><li>Efficiency , Security </li></ul></ul><ul><ul><li>H/W, OS, Network </li></ul></ul>SDLC and DBMS APPROACH
  18. 19. <ul><li>Database Implementation </li></ul><ul><ul><li>Create DB definition, Code, test, populate </li></ul></ul><ul><ul><li>SQL,VB, C </li></ul></ul><ul><ul><li>Train, Document, backup </li></ul></ul><ul><li>RAD </li></ul>Problem Early Prototype Implementation Problem Conceptual Data Model Prototyping Logical Data Base Code & Contents Analyse, Improve Revise DBMS APPROACH
  19. 20. <ul><ul><li>Automated support to assist system Development process </li></ul></ul><ul><ul><li>Draw data models using entity relationship </li></ul></ul><ul><ul><li>Generate code </li></ul></ul><ul><ul><ul><li>Database definition commands </li></ul></ul></ul><ul><ul><ul><li> DBMS </li></ul></ul></ul><ul><ul><ul><li>Compose SQL commands </li></ul></ul></ul><ul><ul><li>An information repository, which contains information needed to generate diagram, forms, reports. </li></ul></ul>CASE TOOLS
  20. 21. <ul><li>System Analyst Analyze Business </li></ul><ul><li>Data base Analyst Data base Component </li></ul><ul><li>User Needs </li></ul><ul><li>Programmer Coding </li></ul><ul><li>Database Administrator </li></ul><ul><li>Computer Architecture experts </li></ul><ul><li>Construct GANTT/PERT Charts </li></ul><ul><li>Review Points </li></ul>Senior DB/System Analyst is LEADER PROJECT DEVELOPMENT
  21. 22. <ul><li>Users View </li></ul><ul><li>Conceptual Schema </li></ul><ul><li>Physical or Internal Schema </li></ul><ul><li>ANSI Architecture </li></ul>User-1 User-2 User-n - - - Conceptual Scheme Internal Scheme Physical DB External Level Conceptual Level Internal Level MODEL / VIEW OF DATABASES
  22. 23. <ul><li>Data Independence is achieved by Inter-level Mapping </li></ul><ul><li>Queries are translated between levels automatically </li></ul><ul><li>Conceptual schema is encapsulated (independent of Database Management Technology) </li></ul><ul><li>Physical schema is also encapsulated (specs to allocate & manage secondary memory) </li></ul>Develop Conceptual Schema Develop User View Physical Schema CA Features Performance Enterprise Data Model User Needs MODEL / VIEW OF DATABASES
  23. 24. <ul><li>Centralized DB System </li></ul><ul><ul><li> </li></ul></ul>Database DBMS DATABASES ARCHITECTURES
  24. 25. Distributed DB System DATABASES ARCHITECTURES Data Manager Transaction Manager DB
  25. 26. Client Server DB <ul><li>Client : User System Interface & localized Data </li></ul><ul><li>Sever : Shared Data </li></ul>CLIENT CLIENT SERVER DB DBMS DATABASES ARCHITECTURES
  26. 27. Client Server (2 Tired) <ul><ul><li>Thin Client / Fat Server </li></ul></ul><ul><ul><li>Fat Client / Thin Server </li></ul></ul>DB Server Server DATABASES ARCHITECTURES
  27. 28. Client Server (3 Tiered) DB Server Client (s) DATABASE Dept. Server (Application Server) Organizational Server (Higher Level) Merging or Data DATABASES ARCHITECTURES
  28. 29. DB –Driven Web Applications <ul><li>Advantages </li></ul><ul><li>Multi –processing </li></ul><ul><li>Advantages of each computer platform (PCs, Servers) </li></ul><ul><li>Mix Client Technologies (Thin Client) </li></ul><ul><li>Processing close to data , reduces traffic </li></ul><ul><li>Open System Standards </li></ul>DB Server WEB+Application Server Internet DATABASES ARCHITECTURES
  29. 30. Summary <ul><li>General steps in DB development </li></ul><ul><li>ISA, EDM </li></ul><ul><li>DB Architectures </li></ul>