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Data Management in Information Systems

Explore why data management is crucial in information systems, ensuring data is available, current, accurate, and secure. Learn about file processing and database processing.

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Data Management in Information Systems

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  1. Data Management in Information Systems www.assignmentpoint.com

  2. Why Data Management is Needed in Information Systems • Data must be kept usable by the system • Data management ensures that the data is: • Available • Current • Accurate • Secure www.assignmentpoint.com

  3. File Processing • File is the simplest way to store data • A file is made up of records • A record is made up of fields • A field is made up of characters • Records are uniquely identified by a key (also called a key field in each record) • Key fields are coded fields of characters www.assignmentpoint.com

  4. File Processing (cont’d) www.assignmentpoint.com

  5. File Processing (cont’d) • File organization • Sequential • Records are organized in sequence • Records can only be accessed sequentially • Key field in a record in a sequential file identifies which record was retrieved www.assignmentpoint.com

  6. File Processing (cont’d) • File organization (cont’d) • Sequential (cont’d) www.assignmentpoint.com

  7. File Processing (cont’d) • File organization (cont’d) • Direct • Also called random • Where the record is stored is determined by the key field value • Can be retrieved in random order • Must use secondary storage with random access capabilities www.assignmentpoint.com

  8. File Processing (cont’d) • File organization (cont’d) • Direct (cont’d) www.assignmentpoint.com

  9. File Processing (cont’d) • File organization (cont’d) • Indexed • Also called indexed sequential • Actually two files - a data file and an index file • Data file is sequential with records in increasing order by key field www.assignmentpoint.com

  10. File Processing (cont’d) • File organization (cont’d) • Indexed (cont’d) • Index file has one record per record in the data file • Index record contains the key value and location of each record in the data file • Can be accessed sequentially or randomly, requiring random storage www.assignmentpoint.com

  11. File Processing (cont’d) • File organization (cont’d) • Indexed (cont’d) www.assignmentpoint.com

  12. File Processing (cont’d) • File management • Files are kept current by regular updates • Updates can mean • Adding records • Deleting records • Changing data in records • Computer programs perform updates www.assignmentpoint.com

  13. File Processing (cont’d) • File management (cont’d) • Sequential files must be recreated • Direct and indexed files are updated • Validation: process of checking data as it is entered into a file to ensure accuracy • Availability is accomplished through regular backups and offsite storage • Security prevents unauthorized access www.assignmentpoint.com

  14. File Processing (cont’d) • Advantages • Simple to use • Some information systems only need a single file • Sequential files are used in simple cases • Direct or indexed files are used for random access • Direct files are not common www.assignmentpoint.com

  15. File Processing (cont’d) • Disadvantages www.assignmentpoint.com

  16. File Processing (cont’d) • Disadvantages (cont’d) • Data may be duplicated • Requires extra storage • Difficult to access data from more than one file at a time • Programs must have specific instructions for each file, creating dependencies www.assignmentpoint.com

  17. Database Processing • Databases can overcome some file processing disadvantages • All data is stored together • A database management system or DBMS allows creation, update, and deletion of data • Users and programmers access data through the DBMS www.assignmentpoint.com

  18. Database Processing (cont’d) www.assignmentpoint.com

  19. Database Processing (cont’d) • A database is a collection of data and relationships • Data in the database is arranged into related groups, similar to records • The user sees only a single set of stored data • Relationships describe the ways in which the groups of data are related www.assignmentpoint.com

  20. Database Processing (cont’d) www.assignmentpoint.com

  21. Database Processing (cont’d) • Database management • Data is made available in the database through the DBMS • Access can involve one or many groups of related data • DBMS handles security and validation www.assignmentpoint.com

  22. Database Processing (cont’d) • Advantages • Reduced data duplication • Easier to process groups of data • Programs aren’t dependent on the organization of the data www.assignmentpoint.com

  23. Database Processing (cont’d) • Disadvantages • Expensive • Data can be more vulnerable since all data is stored in one place instead of several files • Databases can be complex to process www.assignmentpoint.com

  24. Database Organization • Data relationships • The key to database processing is the relationships between the data • Different types of relationships are used in different databases • 3 Main relationships: 1:1, 1:M, M:M www.assignmentpoint.com

  25. Database Organization (cont’d) • Data relationships (cont’d) • 1:1 www.assignmentpoint.com

  26. Database Organization (cont’d) • Data relationships (cont’d) • 1:M www.assignmentpoint.com

  27. Database Organization (cont’d) • Data relationships (cont’d) • M:M www.assignmentpoint.com

  28. Database Organization (cont’d) • Types of databases • Data is organized in a way that people can easily understand • 3 Main types • Hierarchical • Network • Relational (most databases) www.assignmentpoint.com

  29. Database Organization (cont’d) • Types of databases (cont’d) • Hierarchical www.assignmentpoint.com

  30. Database Organization (cont’d) • Types of databases (cont’d) • Network www.assignmentpoint.com

  31. Database Organization (cont’d) • Types of databases (cont’d) • Relational www.assignmentpoint.com

  32. Database Organization (cont’d) • Types of databases (cont’d) • Relational (cont’d) www.assignmentpoint.com

  33. Database Organization (cont’d) • Types of databases (cont’d) • Comparison of database types • Hierarchical (first type) • Developed in 1960s • Good for data such as family trees • Not good for M:M relationships www.assignmentpoint.com

  34. Database Organization (cont’d) • Types of databases (cont’d) • Comparison of database types (cont’d) • Network • Developed in 1970s • Good for complex data • Can do M:M relationships www.assignmentpoint.com

  35. Database Organization (cont’d) • Types of databases (cont’d) • Comparison of database types (cont’d) • Relational • Developed in 1970s • Became widespread in 1980s • Easiest for users to understand • Processing is relatively simple www.assignmentpoint.com

  36. Database Organization (cont’d) • Object-oriented databases • Stores objects: a combination of data and its processing instructions • Objects in the database are persistent, vs. transient objects in programs • Not yet widespread, but growing • Hybrids are called object-relational www.assignmentpoint.com

  37. Common Database Software • DBMSs can be hierarchical, network, or relational • Mainframe DBMSs developed in 1960s • Minicomputer DBMSs developed in 1970s • PC DBMSs developed in 1980s • Networked computer DBMSs in 1990s www.assignmentpoint.com

  38. Common Database Software (cont’d) • Personal computer database software • Simplest form of DBMS • Most use relational approach • Provide update, reporting, forms design, and programming languages • Cost between $100 and $500 • Examples: Access, Paradox, dBase www.assignmentpoint.com

  39. Common Database Software (cont’d) • Multiple-user computer database software • Large, complex programs • Cost $25,000 to $250,000 • Require specially trained computer professionals to utilize and maintain them • Examples: IMS (hierarchical), IDMS (network), DB/2 and Oracle (relational) www.assignmentpoint.com

  40. Common Database Software (cont’d) • Networked computer database software • Runs on a database server • Examples: Oracle, Informix, Sybase (all relational) • Client computers use software to access data on DB servers • Example: PowerBuilder www.assignmentpoint.com

  41. Common Database Software (cont’d) • Networked computer DBMS (cont'd) • Cost depends on licenses • Object-oriented DBMSs can also be networked computer DBMSs • Examples: GemStone, ObjectStore • Distributed DBs: When parts of a database are stored on different servers www.assignmentpoint.com

  42. Using Database Software (cont’d) • Query languages • Allows users to retrieve and update DBs • Enters an instruction or command into the DBMS, which returns the result • SQL=Structured Query Language • SQL is used with relational databases • Query-by-example (QBE) helps users • QBE is used with relational databases www.assignmentpoint.com

  43. Using Database Software (cont’d) • Query languages (cont’d) www.assignmentpoint.com

  44. Database Use In Information Systems • Personal databases are used in individual information systems • Simple databases • Small amounts of data • Used by only one person • Example: Sales database for a sales person www.assignmentpoint.com

  45. Database Use In Information Systems (cont’d) • Shared databases are used for organizations, workgroups, other multiple-user situations • Large amounts of data • Complex designs • Used by many people • May use views to restrict access by users to specific parts of a database www.assignmentpoint.com

  46. Database Warehouses • Most databases contain current data • Data warehouses contain historical data • May be several databases combined into one large database • Data warehouse data is typically used to analyze trends and spot problems • Datamarts are small data warehouses with data relating to a specific subject www.assignmentpoint.com

  47. Database Administration • Large, complex databases require special computer professionals to manage the data • Database administrators or DBAs design, develop, and implement databases • DBAs also control access/security www.assignmentpoint.com

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