Sorting & Extracting Data


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Sorting & Extracting Data

  1. 1. Using Databases to Facilitate Learning and Develop Inquiry SkillsDefinitions, Planning and Design Issues, Higher-Order Thinking Skills, Advantages and Disadvantages
  2. 2. What Can You Do with a Database ?Databases can be used to:4  Analyze, collect, and manipulate data.4  Foster problem-solving activities (planning, organizing, categorization, dissemination, and logical thinking).4  Create an environment for inquiry.4  Classify and group data.
  3. 3. Definitions4  A database is a collection of related fields grouped into records.4  Fields are the smallest unit of data and are useless by themselves. All fields related to a particular subject form records.4  Records are used to represent all the information pertaining to one person, place, topic, or thing.4  The conglomeration of records forms the database.
  4. 4. Steps to Complete Before Planning a DatabaseThoroughly understand:4  The data to store and manipulate.4  The interdependencies among data.4  The reason why the data exists.4  The types of problems that can be solved using the data.4  The ways data can be managed and manipulated to produce a useable product.
  5. 5. Steps in Planning a Database4  Decide what data fields are needed now and project future needs.4  Define data fields and name them appropriately.4  Establish guidelines for the contents of each field.4  Enter data.
  6. 6. Planning the DatabaseFields contain text or numeric data. Insome databases, they can also containpictures, computations, times, or dates.The definition of fields is a critical part ofplanning the database. In order for thedatabase to be useful, it must have allinformation necessary for solving a givenproblem (i.e., many useful and relevantfields).
  7. 7. Planning the Database4  Fields should contain only one type of data in order to provide uniformity, make the database easy to use, produce consistent results from queries, and make the database more reliable.4  It is best to subdivide fields for accuracy and ease-of-use. Example: Name (John Doe) could become Last Name (Doe) and First Name (John) or Size = 9lbs. 2oz. could be Pounds (9) Ounces(2).
  8. 8. Planning the DatabaseNaming fields is also important. Long,unrelated names should be avoided andreplaced with short, concise, and easilyunderstood titles.Examples:4  City in the USA = City4  Things birds eat = Diet4  Length of reptile = Length
  9. 9. Planning the DatabaseAfter fields have been selected andappropriately named, it is essential to analyzethe field s contents and design applicablerules or guidelines for data entry.Without guidelines or predetermined rangesfor data entry, searching and sorting thesefields will produce inconsistent andinaccurate results.
  10. 10. Some Currently Available Database Packages4  Dbase4  Oracle4  ClarisWorks4  Microsoft Works for Windows4  Access
  11. 11. Database Structures4  Hierarchical4  Relational4  Network
  12. 12. Hierarchical Databases4  This is the simplest type of database.4  The tree structure illustrates this concept.
  13. 13. Hierarchical Databases4  Information is accessed from the top to the bottom (top-down).4  Illustrates a parent-child relationship where each item relates only to the one above and below it.4  Disadvantage – following the hierarchy is sometimes difficult, cumbersome, and time consuming.
  14. 14. Relational Database4  Allows multiple associations using common fields in multiple databases.4  Arranged in a two-dimensional table format.4  Files are known as relations, fields are columns, and records are called rows.4  Performs the following: joining, projection, and selection.
  15. 15. Relational Database4  Used in libraries effectively4  Users must define, create, and implement files. This is not automatically done by the relational database or database management system.4  Disadvantage: there is no way to link fields in a practical manner. Explicit links are formed by relations (or files rather than specific fields contained within files).
  16. 16. Network Databases4  These types of databases have a less rigid structures than the hierarchical model. They permit the use of pointers to establish the shortest path to specific information.4  This model is well suited for transaction processing like those found in banking, inventory control, and airline reservation systems.
  17. 17. Network Databases4  Good for standardized operations.4  Disadvantage: Complex pointer implementation makes modification involved, and requires care to keep established links from being lost.4  When transactions are not predictable or stable, a relational database is a better model.
  18. 18. Products from a DatabaseAfter the database has been created and dataentry has taken place, students or users canproduce reports or lists that sort, extract, andsummarize information from the database. Sort Arrange in ascending or descending order. Extract Produce a subset from the collection of information. Summarize Total amounts or a count of items located.
  19. 19. Data Extraction – Arithmetic and Boolean Operators = Equal to <> Not equal > Greater than >= Greater than or equal < Less than <= Less than or equal AND Include all items OR Include either item NOT Exclude item
  20. 20. Matching Database Functions with a Learning TaskModified from (Table 11-1, pp.259) of Morrison andLowther s Integrating Computer Technology into theClassroom, 2ed. Learning Task Database Function Combine, Match, Sequence Match and Sort Information Compare, Contrast, Sort, Analyze, Query Discriminate, Relate Classify, Identify, List Sort, Query Assemble, Report Report Customization
  21. 21. Advantages of DatabasesApplicability to many different types ofproblems involving:4  Data collection, analysis, and manipulation.4  Comparison, synthesis, and evaluation.4  Relationships between data.4  Arranging, organizing, and collecting data.
  22. 22. Advantages of Databases4  Fast, efficient data access and reporting.4  Built-in search and retrieval functions.4  Good for data integrated from many sources.4  Flexible, user-friendly formats for storing the contents of fields.
  23. 23. Advantages of Databases4  Reduce inconsistencies when users carefully define, enter, and verify data.4  Cost-effective way to generate answers to questions related to information processing needs.4  Save time when data must be located, updated, and retrieved.
  24. 24. Advantages of Databases4  Maintains data integrity when there is a few-to many relationship i.e., only one or two people actually define and update the database, while many use the data contained therein.4  Security is available through protected copies and passwords in many database packages.4  Built-in wizards, templates, and imported data.
  25. 25. Disadvantages of Databases4  Duplication or redundancy.4  Difficulty evolving the database over time.4  Difficulty building the database for complex problems and applications.4  Difficulty defining fields and establishing guidelines for data entry.
  26. 26. Student Misconceptions About Databases4  Queries and Filters are one in the same.4  The most important thing to remember about constructing a database is entering data appropriately.4  Databases are not used for calculation.
  27. 27. Correcting Misconceptions about Databases4  Queries and filters are one in the same Actually, these are different; queries are usually more specific, involve more steps, and utilize more data fields to select required criteria.4  The most important thing to remember about constructing a database is entering data appropriately. This is good, but it is more important to plan the database well by specifying needed data and establishing firm guidelines for data entry.
  28. 28. Queries vs. Filters4  Good situations for a setting a query: 3  Using more than one table for data selection. 3  Performing calculations on selected record values. 3  Viewing only some of the fields in a record.4  Good situations for setting a filter: Viewing only a subset of records.
  29. 29. Disadvantages of Filters 4  Filters allow you to select criteria one field-at-a-time, and they are very restrictive (all criteria must be met before a record is displayed).
  30. 30. Queries4  More powerful selection instrument, because you can use related tables.4  You only display the fields you add to the query.
  31. 31. Correcting Misconceptions about Databases4  Databases are not used for calculation. Although complex formulas and sophisticated computations are better served by other tools, you can create computed fields with numeric data fields and generate some statistical data (averages, minimum and maximum values, standard deviations, and grand totals) for reports.
  32. 32. Correcting Misconceptions about Databases 4  Once data is entered, the database should be used to construct reports. 4  Difference between sorting and indexing. 4  Specifying data types.
  33. 33. Correcting Misconceptions about Databases4  Once data is entered, the database should be used to construct reports. Data should be verified and validated before constructing reports.4  Difference between sorting and indexing. Sorting has to do with the physical arrangement of data, while indexing deals only with the organization of the common key field.
  34. 34. Correcting Misconceptions about Databases Difference between sorting and indexing. Sorting IndexingPhysical arrangement based on Records appear based on howa specified order. Example: they are entered, but a uniquearranging names alphabetically key field contains an– As listed before Bs, etc… Identification number for each record that identifies its position. Example: Abraham, Jane, might be listed after Hinton, Bob, but the key field uses an ID number that appropriated sequences these names alphabetically.
  35. 35. Correcting Misconceptions about Databases4  Specifying data types This is extremely important. If default data types (integer, character, fixed, etc.) are used, comparisons, calculations, and results will be inaccurate. Always specify the data s type to avoid confusion and ensure correctness.
  36. 36. ReferencesBitter, G., and Pierson, M. (2002). Using Technologyin the Classroom. 5th ed. Allyn and Bacon: Boston.Morrison, G., and Lowther, D. (2002). IntegratingComputer Technology into the Classroom. 2nd ed.Merrill Prentice Hall: New Jersey.
  37. 37. SummaryElectronic databases can save time and helpuser s prepare, manipulate, organize, anddisseminate data that answers questions andsolves information processing problems.The database s ability to compile,manipulate, and store large quantities ofinformation in short time periods makes it aviable and useful tool in both education andindustry.