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ICT: TOPIC 8 DATABASES

barrs065 Inglés 44 fichas

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  1. 1Topic 8: DatabasesTopic 8: Databases
  2. 2What is a database?It is a collection of related data. It is possible to add, edit, manage and retrieve data from a database. The structure of a database allows data to be found and used quickly.
  3. 3What is the data type Number (integer)?A whole number (positive or negative)
    but no fractions. e.g. 43
  4. 4What is the data type Number (real)?Any number, including whole numbers and fractions. e.g. 435.256
  5. 5What is the data type Text or string?Letters, numbers or other characters
    such as punctuation marks. e.g. John Smith.
  6. 6What is the data type Date/time?Any time or date; the way the time or
    date is displayed depends on how it is formatted. e.g. 04/10/12 or 12:15:45
  7. 7What is the data type Currency?Money £ (including foreign currency $). e.g. £13.55
  8. 8What is the data type Boolean?Two opposing states e.g. true or false, male or female, yes or no.
  9. 9What is the data type Lists?A list of values, sometimes called a "drop-down" list; only data from the list can be selected. e.g. red, green, blue.
  10. 10What is the data type Picture?Image data, from a digital camera, mobile phone, the internet, a clip-art library or scanned in image.
  11. 11What is the data type Sound?A beep from a barcode reader or
    popular song. e.g. a sound or
    music clip.
  12. 12What is the data type Video?A video introduction to a computer game or a downloaded film/TV programme. e.g. A moving picture.
  13. 13What is a field?It is a single item of data
    within a record.
  14. 14Give some examples of a field.Surname: Text
    Date of birth: date/time
    Selling pricing: currency
  15. 15What is a record?It consists of a collection of
    related fields.
  16. 16Give an example of a record.Pupil's record in a school database only has the fields related to that pupil (surname, forename, date of birth, from, etc.) and not another pupil's data.
  17. 17What is a file?It is a collection of related fields
    (known as a table in Microsoft Access)
  18. 18Give an example of a file.The table of records of all pupils
    in the school.
  19. 19What is a key field?A key field uniquely identifies each
    record. No two records have the
    same data in their key field. Also
    known as Primary Key.
  20. 20What is the purpose of the Key Field?The purpose of the key field is to be able to refer to an individual record using a single field. This often takes the form of an identity number, membership number or bar code.
  21. 21What is Validation?Data entered in to a database must be sensible or we get GIGO. Validation methods can only ensure reasonable and sensible data is input in to a system, but there is no certainty that the data is correct.
  22. 22What are validation rules?Validation rules are needed for some fields. As data is entered it is checked to see that it obeys the rules; any data that does not obey the rules is not accepted. You can also set validation text - the text that appears if the data is not acceptable.
  23. 23What is the validation method Range Check?The data entered must be in a sensible range. e.g. If a test is out of 100 marks then only marks in the range of 0 to 100 are acceptable.
  24. 24What is the validation method Type Check?This ensures that the data is of the correct type. e.g. If the number of rooms in a house is being recorded then only an integer (whole number) will be accepted.
  25. 25What is the validation method Format/picture Check?If the data entered has a particular pattern e.g. a postcode or car reg then an input mask can be used to force the data to conform to the rule. e.g. Input mask for a database would be LLN NLL e.g. ME1 3BY, where L is a letter and N is a number.
  26. 26What is the validation method Length check?The length of the input is checked for the number of characters used. e.g. If a forename is being entered it is reasonable to assume that it will be between 2 and 18 characters long.
  27. 27What is the validation method Presence Check?Some data has to be entered. e.g. If you were ordering goods from the internet you would have to give them your address and the item you were ordering. An error would occur if this data was not present and would not allow the processing of the order to continue.
  28. 28What is the validation method Lookup list?If the data entered consists of a limited number of possible entries then the computer can compare the entry with a list of allowed answers. e.g. If the predicted grade for an exam can only be A to E and U, only these inputs are allowed.
  29. 29What is a report?A report is a printed document that contains data from the database , organised and analysed in a certain way. A report from a student database might list the students in each class in alphabetical order.
  30. 30What is a form?Forms are used to make data entry more attractive and secure rather than entering data into raw tables.
  31. 31Why is a form more secure?It is more secure for looking through and displaying the data because the person entering the data need not see all other data or even the other fields. It also allows instructions to be entered.
  32. 32What is a calculated field?For example, a person's age is never included because it changes day by day. If you want to use age in a report it must be calculated. This result is known as a calculated field.
  33. 33What are the 4 uses of a database?-Add, change or delete records
    -Search for a particular record
    -Sort the records into a given order
    -Print reports about some aspect of the database.
  34. 34What are 6 benefits of using a database?-Fast access
    -Easy to edit
    -Validation
    -Reports
    -Sharing
    -Security
  35. 35List and describe 7 operators.= - equals, < - Less than, > - Greater than, <> - Not equal to, AND - Data is only listed where both conditions are true, OR - Data is only listed where either or both conditions are true, LIKE - Where a perfect match is needed.
  36. 36List and describe 5 wild cards* - Any number of characters, ? - Any character, [ ] - Any character in the brackets, [ - ] - Any character within a range of characters, ! - Any character not in the brackets.
  37. 37Why sort data?Easier if lists are printed as reports and you can identify best customer by amount they have spent - sort them according to total amount spent.
  38. 38If data is secure then...- It cannot be destroyed
    - It cannot be accidently or maliciously altered
    - It cannot fall into the hands of unauthorised people.
  39. 39What are the consequences to a business of having non secure data?- Loss of customers: unhappy customers go elsewhere
    - Payments for goods not being received
    - Bad publicity: all businesses rely on a good reputation
    - Management unable to make decisions due to a lack of information
  40. 40List types of physical security.Locks on doors, Alarms, ID cards and Biometric systems
  41. 41Describe passwords.Authorised users are given a username. Each user also has a password that proves the user is really the one whose username is given. Using passwords is a method of authentication.
  42. 42Describe what access rights give.No right to access the file, read access (user can view file but not alter it) and write access (allowing the user to alter the contents of the file)
  43. 43Describe back-ups.A back-up is a second copy of the data. If a problem arises with the data file, then the back-up copy is used.
  44. 44What are back-ups?Saved on to removable media (CD, DVD, memory sticks), stored at a separate location in a locked room or fireproof safe and made regularly (every day)

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Fichas sobre ICT: TOPIC 8 DATABASES, creado por barrs065 el 06/02/2015.
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