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Chapter 5

Chapter 5. Introduction to Database Management. Data. Vital organizational resource Data resource management is a managerial action that applies technology to the task of managing data. Data Concepts.

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Chapter 5

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  1. Chapter 5 Introduction to Database Management

  2. Data • Vital organizational resource • Data resource management is a managerial action that applies technology to the task of managing data

  3. Data Concepts • Character - a character is a single element of data and can be alphabetic, numeric, or some other ‘legal’ character • Field - A field is a grouping of characters that describes an attribute of and entity • Record - A logical grouping of fields relating to the same entity

  4. Data Concepts cont. • Records can be fixed length or variable length • File - A group of related records is a file or commonly known as a table. Tables are classified by levels of permanence • transaction - daily sales or production • master - employee_master, item_master • history - usually backups

  5. Database • A database is an organized and integrated collection of records • Data in a database is independent of the programs that use the data

  6. The Database Management Approach • Foundation of modern data management • Database management approach - data records and objects are consolidated and accessed by multiple application programs • Database Management System - software interface between users and databases - uses DBMS software to create, interrogate, update, and maintain a database to provide information for users

  7. Database Management Approach • Three common activities • update and maintain common databases to reflect transactions and organizational data • provide information for end users applications • provide easy interface for ad hoc (on demand) requests, generation of reports, and database interrogation

  8. DBMS • A database management system is a set of programs that control four necessary functions in the database world • database development • database interrogation • database maintenance • application development

  9. Database Development • Database management application packages allow for the development of databases • Database administrators (DBAs) use a data definition language to design and develop tables, relationships, and a data dictionary • Data dictionary - A catalog or directory of information about the data (meta data)

  10. Database Interrogation • Database interrogation (extracting data/information) is accomplished by using a query or a report generator • Query language offer • immediate response to request • no difficult programming

  11. Database Interrogation cont • A report generator offers • immediate video or paper response to queries • No difficult programming • Can format or design reports to meet individual needs/preferences

  12. SQL and QBE • Structured Query Language - A ‘standardized’ language that allows for simple database interrogation • Basic form for SQL statement is • Select ….. • From…… • Where…..

  13. SQL and QBE • Query By Example - query language similar to SQL except the query is written in the ‘background’ as the user points and clicks • Graphical and Natural queries are essentially point and click utilities that are translated into SQL

  14. Database Maintenance • Database maintenance occurs through transaction processing and the ACID functions • A - add • C - change • I - inquiry • D - delete

  15. Application Development • Databases are the backbone of system development • A data manipulation language allows for necessary data handling needs

  16. Database types • There are several major types of databases • operational databases • data warehouses • distributed • external

  17. Operational Databases • These databases store data that is necessary for the operations of an organization such as transaction databases, subject area databases • Very important for this type of database to be accurate

  18. Data Warehouse • A data warehouse stores data from previous years or time periods that are not necessary for the current operations of an organization • May be subdivided into DATA MARTS that contain certain data elements • Data mining is the process of extracting data, trend analysis, and historical patterns

  19. Distributed Databases • Can be copies of organizational databases that reside in different geographical areas, on different servers (for functional areas), or on handheld or labtop devices

  20. External Databases • Privately owned online databases usually accessible for a fee • Can be free • Usually associated with Internet

  21. Data Resource Management • Data resource management involves several tasks • Database Administration • Data Planning • Data Administration

  22. Database Administration • Provides for the development and maintenance of the data dictionary • Monitoring of database and resource performance • Enforcement of standards and security

  23. Data Planning • Corporate planning and analysis function • Data architecture for firms data needs (must fit within the strategic missions) • Should be a major issue in strategic planning • Long range planning

  24. Data Administration • Establishment and enforcement of policies and procedures for managing data resource • Collect, store, and disseminate information in an organizationally standardized manner • Planning and support of data and the establishment of data planning activities • Develop policies and standards for database design

  25. Benefits/Limitations • Reduction of replication and redundant data • Data integration • Users can obtain information in more usable form • Programming is simplified • Data integrity and security is ensured

  26. Benefits/Limitations • Complexity • Can be very expensive to develop and maintain • Large investment LARGE • More difficult processing procedures (must work through and additional layer of software)

  27. Technical Foundationsof Database Management • Data resources must be organized in a logical manner • This allows for easy access, efficient processing, quick retrieval of data • Multiple structures………...

  28. Hierarchical • Early mainframe packages used the hierarchical structure of database management • Treelike structure • Records are dependent on a root record • Relationships are one to many (only related to the element above it)

  29. Network Structure • Able to represent more complicated structures and relationships • Still used in many mainframe packages • Allows for many to many relationships • Access is not one dimensional and can follow many paths

  30. Relational Structure • Most popular in use today • Used by most micro databases, also used in mini systems and mainframe systems • Data elements stored in tables • Table related through the use of a common field

  31. MultidimensionalDatabase Structure • Variation of the relational model • Compact and easy to use • Support OLAP

  32. Object OrientedStructure • The key technology of multimedia web-based applications • An object consists of data plus the instructions to be applied • Inheritance is the acceptance of characteristics of other objects

  33. Database Access • Databases rely on identifying characteristics called key fields or in the case of older DB types a pointer field • Key field is the primary identifier • Must be unique among all other records

  34. Sequential Access • Records are stored in a specific order based on the key field • Sequential processing is fairly fast when dealing with similar records (fixed length) • Requires sorting, indexing, etc. • Best in batch processing situations

  35. Direct Access • No fixed arrangement of records • Works with immediate response systems • Three ways for direct access to occur • Key transformation • Index • Indexed Sequential access

  36. Next Week • Chapter 5 data base planning and design • Chapter 6 IS for Business Operations and E-commerce

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