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9IPT: Databases, databases!

posted Nov 8, 2012, 2:21 PM by Eddie Woo   [ updated Nov 8, 2012, 2:52 PM by Unknown user ]
With just over a week to go till your first HSC assessment, we don't have time to finish this entire topic. But we do have more than enough to get started on this topic and sink our teeth into some big ideas that will appear in the next exam, before we conclude this topic at the end of the term. 

Whether you recognise it or not, your life depends on databases. Every day, numerous things that you take for granted rely on massive databases doing their job without us noticing. Alarm clock on your phone? Listening to music while you study? Catching a bus or train? Going to roll call (or signing on late)? Working out what classroom to walk to? Buying groceries from the supermarket? Databases are there at every turn. They're tremendously important to the modern way of life. 
  1. Define a database.

  2. Describe the primary elements of a basic database.

  3. Distinguish between flat-file and relational databases.

  4. Consider this example database.
    • Is it a flat-file or a relational database?
    • Populate it with appropriate data.
    • Explain how the database could be made more efficient.

  5. In groups, identify ten examples of other databases that you use or benefit from on a daily basis. For each:
    • Identify whether it is flat-file or relational.
    • Describe its primary elements.
    • Give a concrete example of the data contained it.

  6. Download this sample database and then:
    • Identify the type of database contained in the file, and justify your choice (think back to the definitions).
    • Describe the entities represented in this database.
    • Identify three instances of analysing that are occuring in this database, and explain their usefulness.
    • Give examples of records and fields in this database.
    • Define a data dictionary.
    • Construct a data dictionary for the first 'sheet' in the database, titled "HSC Summary".
    • Discuss the use of an electronic format, over against a non-computer-based alternative, to store this database.

  7. Define the three main data types in a database

  8. Describe the six main numerical data types, with reference to their unique characteristics.

  9. Explain (with examples) why numbers will occasionally be represented with the text/char data type instead.



    The following questions relate to the data below, which represents example data from the "renter" table in a real estate agent's database.

  10. Construct a data dictionary to describe the data stored in the table.

  11. Justify your choice of data types and storage sizes.

  12. Calculate the approximate storage required if the table contains 1000 records.

  13. Renter Code
    Telephone Number
    Postcode 
    Rent 
    Occupation Date 
    Under Lease 
    458703
    9123 4567
    2056 $230.00
    3/12/2005 Y
    594223
    9567 4321
    2057 $395.00 4/3/1999 N
    934882
    02 46322345
    2570 $410.58 31/10/2001 N
    239922
    4589 7654
    2690 $195.00 4/3/2006 Y
    345533
    4322 8933
    2856 $240.00 16/7/2006 Y
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