Y11Term2HolidayHWSol

Document Sample
Y11Term2HolidayHWSol Powered By Docstoc
					Year 11       Software Development                          Term 2 Holiday Homework

Chapter 10 Database Management pgs 512 to 546

Part 1. Complete the following sections (pgs 545 and 546). Write the question and answer:

          True/False
   1. Data is a collection of unprocessed items, which can include text, numbers, images, audio
       and video. – TRUE
   2. A database management system allows user to create forms and reports from the data in
       the database. – TRUE
   3. A range check ensures users enter only numeric data in a field. – FALSE
   4. A check digit often confirms the accuracy of a primary key value. – TRUE
   5. Databases require less memory, storage and processing power than a file processing
       system. – FALSE
   6. A report is a window on the screen that provides areas for entering or modifying data in a
       database. – TRUE
   7. Continuous backup is a backup plan in which all data is backed up whenever a change is
       made. – TRUE
   8. A relationship is a link within the data in a database. – TRUE
   9. Normalisation is the process designed to ensure the data within the relations (tables) is
       duplicated so that it is not lost. – FALSE
   10. The data in a distributed database exists in many separate locations throughout a network
       or the Internet. – TRUE


          Multiple Choice
   1. TIMELY (B) information has an age suited to its use.
   2. In some tables, the primary key consists of multiple fields, called a (A) COMPOSITE KEY.
   3. (D) FILE MAINTENANCE procedures include adding records to, modifying records in,
       and deleting records from a file.
   4. A range check (B) DETERMINES WHETHER A NUMBER IS WITHIN A SPECIFIED
       RANGE.
   5. All of the following are strengths of the database approach, except (A) LESS
       COMPLEXITY.
   6. Because the (B) DATA DICTIONARY contains details about data, some call it metadata
       (meta means more comprehensive).




                                              Page 1 of 6
7. Many organisations adopt the (B) PRINCIPLE OF LEAST PRIVILEGE policy, where
   users’ access privileges are limited to the lowest level necessary to perform required tasks.
8. The database analyst (DA) (A) DECIDES ON THE PROPER PLACEMENT OF FIELDS.




                                         Page 2 of 6
          Matching
   1. Field Name – uniquely identifies each field.
   2. Field size – defines the maximum number of characters a field can contain
   3. Data type – specifies the kind of data a field can contain and how the field is used.
   4. Primary key – field that uniquely identifies each record in a file
   5. Query language – consists of simple, English-like statements that allow users to specify the
       data to display, print, or save.
   6. Log – listing of activities that modify the contents of a database.
   7. Recovery utility – uses the logs and/or backups to restore a database when it becomes
       damaged or destroyed.
   8. GIS – database that stores maps and other geographic data.
   9. Data modeller – person who focuses on the meaning and usage of data
   10. Database administrator – creates and maintains the data dictionary, manages security of
       the database, monitors the performance of the database, and checks backup and recovery
       procedures.


          Short Answer
     1. What is validation?
It is the process of comparing data with a set of rules or values to find out if the data is correct.
         What are five types of validity checks?
It is a check that analyses entered data to help ensure that is correct. See page 523 for details.
          Alphabetic/Numeric check
          Range Check
          Consistency Check
          Completeness Check
          Check Digit

     2. Why is data redundancy a weakness of file processing systems?
It is a weakness because the same data is stored in multiple files. If a change is made to data, it
needs to be changed in all files. This wastes a lot of time and also can cause problems with
incorrect data if data in all files is not updated.

         Why is isolated data a weakness of file processing systems?
It is a weakness because it can be difficult to access separate files in separate departments. Sharing
data from multiple files is a complicated procedure and usually needs an experienced programmer
to be able to do this.

   3. What is the database approach?
A system used to store and manage data in which many programs and users share the data in a
database.

       Describe five strengths of the database approach. See pages 525 and 526 for details.
      Reduced data redundancy - Specific data is stored in one file only, this reduces memory
       wastage and reduces duplicate data

                                                Page 3 of 6
      Improved data integrity - when files are changed they make changes to one file instead of
       multiple files, reducing inconsistencies
      Shared data - Data can be shared over networks or the internet with the use of a database
       program, this allows for greater access and implementable restrictions based on user
       privileges.
      Easier access - Databases can be implemented with a friendly user interface allowing less
       advanced users to be able to use the system
      Reduced Deployment time - Databases are easier and faster to construct a file processing
       system, as modern databases come with development tools

    4. Describe how you might use a Simple Query Wizard.
Used to simplify the query process – Firstly select the fields you want to be displayed in your
report window. Secondly request a file or general name that the database can search for. Thirdly
manually look through the results page to find the queried data.
See page 528 and 529.

       What is query by example?
A feature that has a graphical user interface to assist users with retrieving data See example on
page 529.

    5. What are the advantages of object-oriented databases?
These databases store data in objects. An object is an item that contains data, as well as the actions
that read or process that data. Advantages include:
     Can store more types of data
     Access this data faster
     Allow programmers to reuse objects.

   Describe four examples of object-oriented databases.
    Multimedia database – stores images, audio clips, and/or video clips.
    Groupware database – stores documents such as schedules, calendars, manuals, memos
      and reports.
    Computer-aided design database – stores data about engineering, architectural and
      scientific designs.
    Hypertext database -contains text links to other types of documents.
    Hypermedia database – contains text, graphics, video and sound.

Part 2. Define the following terms:

   1. Backup – duplicate of a file, program or disk placed on a separate storage medium that can
       be used if the original is lost, damaged, or destroyed.
   2. Data dictionary – a DBMS element that contains data about each file in a database and each
       field in those files.
   3. Data type – specifies the kind of data a field in a database can contain and how the field
       can be used.
   4. Data mining – process sued with data warehouses to find patterns and relationships
       among data.
   5. Data warehouse – huge database that stores and manages the data required to analyse
       historical and current transactions.

                                               Page 4 of 6
   6. Distributed database – database in which the data exists in many separate locations
       throughout a network or the Internet.
   7. File processing system – system used to store and manage data in which each department
       or area within an organisation has its own set of files.
   8. Garbage in/garbage out – computing phrase that points out the accuracy of computer
       output depends on the accuracy of the data input.
   9. Multidimensional database – database that stores data in dimensions. These multiple
       dimensions, sometimes known as hypercube, allow users to access and analyse any view of
       the database data.
   10. Object-oriented database – database that stores data in objects. An object is a database item
       that contains data, as well as the actions that read or process the data.
   11. Primary key – field in a database that uniquely identifies each record in a file.
   12. Query language – language used with databases that consist if simple English-like
       statements that allows users to specify the data to display, print or store.
   13. Recovery utility – DBMS feature that uses logs and/or backups to restore a database when
       it becomes damaged or destroyed.
   14. Relational database – database that stores data in tables that consist of rows and columns,
       with each row having a primary key and each column having a unique name.
   15. Structured Query Language – SQL – query language used with database that allows users
       to manage, update and retrieve data.
   16. Validation – process of comparing data with a set of rules or values to find out if the data is
       correct.


Part 3. Summarise the following Chapter Review questions (page 542):

   1. What is a database and how does a database interact with data and information?
A database is a collection of data organized in a manner that allows access, retrieve, and use of
data. A database management system can create a database, which allows users to add, delete or
modify the data and form reports from the data.


   2. What is data integrity, and what are the qualities of valuable information?
Data integrity identifies the quality of data. Generally valuable data is accurate, verifiable, timely,
organized, accessible and cost effective. These qualities if done correctly improve data integrity
and therefore making the data more valuable.


   3. What is meant by the terms character, field, record and file?
A database is usually based on a hierarchy, from largest to smallest.
Data File- is a collection of records on a storage device
Record- is a group of related fields


                                               Page 5 of 6
Field- is a combination of related characters. This is the smallest piece of data a user can access.
Character- is a letter, number or any symbol that can be recognised as a byte, one byte represents
one character
   4. What are validation techniques?
File maintenance refers to updating new files modifying existing files and deleting old files so the
database current and accurate. Validation techniques make sure the data entered is correct by
comparing the values against a set of rules. Validation checks can occur during or after the data
has been entered.


   5. How is a file processing approach different from the database approach?
In a File processing approach each department has its own set of files. This leads to problems
when different departments try to access each other’s files. In a database approach the data is
pooled and can be accessed by any department however databases are generally more complex
and data is more vulnerable then data in a file Processor.




                                              Page 6 of 6

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:8
posted:12/16/2011
language:English
pages:6