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MIS 710 Module 0 Database fundamentals

MIS 710 Module 0 Database fundamentals. Arijit Sengupta. Structure of this semester. MIS710. 1. Design. 2. Querying. 4. Advanced Topics. 0. Intro. 3. Applications. Database Fundamentals. Conceptual Modeling. Query Languages. Java DB Applications – JDBC. Transaction

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MIS 710 Module 0 Database fundamentals

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  1. MIS 710 Module 0Database fundamentals Arijit Sengupta

  2. Structure of this semester MIS710 1. Design 2. Querying 4. Advanced Topics 0. Intro 3. Applications Database Fundamentals Conceptual Modeling Query Languages Java DB Applications – JDBC Transaction Management Relational Model Advanced SQL Data Mining Normalization Newbie Users Designers Developers Professionals

  3. Today’s buzzwords • Organizational data cycle • Database • Database Management Systems • Data Independence • Centralized Database Systems • Client-Server Database Systems • Distributed Database Systems

  4. Objectives of today’s lecture • Know common database terminology • Understand requirements and uses of data • Know the differences between databases and flat files • Realize the importance and need for databases in problem-solving • Understand the different types of databases and their differences

  5. Data: A Resource • The Success of an organization depends on efficient use of its resources: • Buildings, factories, equipment • Technical know-how • Human resources • Data • Data: An important organizational resource

  6. User Decisions Knowledge Actions Data Information The Organizational Data Cycle

  7. Electronic Data • Why? • Large volume in a small space • Ease of sharing • Ease of use • Data analysis • How? • File-based system versus databases

  8. Legacy (File-based) Systems • Uncontrolled data redundancy, • Data inconsistency • Poor data sharing • Difficult to keep up with changes • Record format Vs. user requirements • Programs Vs. record format • Low productivity • High maintenance cost

  9. So what is a database? • According to Oxford English Dictionary: “A structured collection of data held in computer storage; esp. one that incorporates software to make it accessible in a variety of ways” • So does it make pretty much every collection of data a “database”?

  10. The Database • The data itself PLUS The data definitions (metadata), applications, queries and visualizations

  11. Database Approach • Non-redundant collection of logically related facts • representing some aspect of the real world • the data itself plus the data definitions • Permits sharing • Consistent representation for each piece of data • Avoids (minimizes) redundancy • Allows different user views • Users are isolated from most changes

  12. Why Databases? • Independence from representation formats • Control redundancy and consistency • Ensure integrity/security • Better scalability • Allow ad hoc access • Better maintenance • Better concurrency

  13. View Conceptual Physical Data Independence • Does data have to be part of programs? • Do we need to change one if the other changes? • Three-tier architecture of databases What the users see How we model data How data is stored

  14. Access Flexibility • Easy to ask ad-hoc questions • No need for separate codes • User-friendly interface • Command-based (e.g., SQL) • Graphical (e.g., QBE)

  15. Data Integrity • Ensures that the stored data are consistent and correct • Easy to define global rules • customer_age > 21 years • number_of_credits < 18 • Can allow multiple users to access data without compromising on data integrity

  16. Data Security • Access definition • Global • Local • Uniform access authorization

  17. Data Redundancy • Data need not be replicated • Less wastage of storage space • Less data anomaly • Reduced and controlled redundancy • Tighter control of replicated data

  18. Standardization • Everybody talks the same talk. • Less chance of misunderstanding • Easier to interpret other’s data • Easier to merge • Useful when several organizations combine to form one.

  19. Productivity and Maintenance • Increase in productivity • User-friendly interface • Independence from specific data structure • Easier maintenance • Less code to maintain • The DBMS is the bulk of the code. • Ad-hoc queries make it possible to make do with much less code. • The vendor makes revisions of the DBMS. • Economy of scale

  20. Productivity vs. Maintenance

  21. Disadvantages of Databases • Software complexity • Processing inefficiency • Need for co-ordination • Organizational impact • Risk

  22. DBMS • A Specialized piece of software that sits between the data and its users. DatabaseManagement System Intension + Extension Data

  23. DBMS Functions and Users • Four major uses of a DBMS package • Database Development, Interrogation, Maintenance, and • Application Development • Automated tools for design, query, and application development • Database users • Database administrators ( DBAs ) • Database designer • End Users

  24. Centralized Database Systems Database

  25. Client/Server Database Systems Client Database Server Client

  26. Database Server Database Server Database Server Distributed Database Systems

  27. Summary • Data is essential for an organization • A Database is usually the most effective way of storing and organizing data • File-based Vs. database systems • Database system properties • Types of database systems

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