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Flashcards

IT- Topic 8

Emer Neave Inglês 49 flashcards

Flashcards do conjunto (49)

  1. 1databaseis an organised 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
  2. 2list ten data typesNumber(integer), number(real), text or string, data/time, currency, Boolean, lists, picture, sound, video
  3. 3give an example and description of the data type number(integer)e.g. 43
    description- a whole number( positive or negative) but no fractions
  4. 4give an example and description of the data type number(real)e.g. 435.256
    description- any number including whole numbers and fractions
  5. 5dive an example and a description of data type text or stringe.g. John Smith
    description- letters, numbers,or other characters including punctuation mark
  6. 6give an example and description of date/ timee.g.- 04/11/12, 12:15:45
    description- any time or date; the way the time or date is displayed depends on the type of formatting
  7. 7give a description and example of the data type currencye.g.£13.55
    description- money( including foreign currency)
  8. 8give an example and description of the data type booleane.g. yes
    description- two opposing states e.g. true or false, male or female, yes or no
  9. 9give an example and description of the data type listse.g. red, green, blue
    description- a list of values, sometimes called a `drop down` list; only data from the list can be selected
  10. 10give an example and description of the data type picturee.g. a picture
    description- image data, from a digital camera, mobile phone, the internet, a clipart library or scanned in image
  11. 11give an example and description of the data type sounde.g. a sound or clip of music
    description- a beep from a barcode reader or popular song
  12. 12give an example and description of the data type videoe.g. a moving picture
    description- a video introduction to a computer game or a download film/ tv programme
  13. 13fielda field s a single item of data within a record
  14. 14recorda record consists of a collection of related data
  15. 15filea file ( known as a table in Microsoft access) is a collection of related fields
  16. 16e.g. of field- surname: text
    - date of birth: date/time
    -selling pricing: currency
  17. 17e.g. of record- pupils record in a school database only has the fields related to that pupil ( surname, forename, date of birth, from, etc) and not another pupils data
  18. 18e.g. File/tablethe table of records of all pupils in the school
  19. 19key fielda key field uniquely identifies each record. no two records have the same data in their key field. also known as a primary key
  20. 20what is the purpose of the key fieldto be able to refer to an individual record using a single field. This often takes the form of an identity number, membership number or barcode
  21. 21e.g. of keyfieldthe pupil id (in the booklet)
  22. 22validationdata entered in to a database must be sensible or we get GIGO. validation methods can only ensure reasonable and sensible data is input into a system, but there is no certainty that it is correct
  23. 23validation rulesare needed for some fields. as data is entered it is checked to see that does not 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
  24. 24give a description and example of range checkthe data entered must be in a sensible range e.g. if a test is pout of 100 marks then only marks in the range of 0-100 are acceptable
  25. 25type check e.g. aswell as descriptionthis ensures that the data is 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
  26. 26format / picture check and e.g.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 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
  27. 27length check and e.g.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 2-18 characters long
  28. 28presence check and e.g.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 the data was not present and would not allow the processing of the order to continue
  29. 29Give an example and description of lookup listIf 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,b,c,d,e or U, only these inputs are allowed
  30. 30Reports and e.gA report is a printed document that contains data from a database, organised and analysed in a certain way. A report from a student database might list the students in each class in alphabetical order
  31. 31FormsForms are used to make data entry more attractive and secure rather than the data into raw tables
  32. 32Calculated fieldsNot all data needed in a report may be present in a database. For example a persons age is never included because it changes by the day. If you want to use age in a report it must be calculated. This result is known as a calculated field. The solution is for the database to use the recorded date of birth to calculate the age by subtracting the date of birth from the date of the report
  33. 33Uses of databases- 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. 34Updating records and e.gRecords do not stay the same forever. They will need to be updated at some point. For example people getting married and change their surname, people move and change their address or prices of goods change
    - add a new record when a new pupil arrives to a new school, edit existing records when someone moves house, delete an old record when an employee leaves a job
  35. 35Searching for dataOne main use of a database is to find information quickly. To search for information you use a query. You are 'querying the database'
  36. 36What does a query diIt specifies what records you are searching for and what fields from the records you would like to display
  37. 37Simple query searchLooks for data in one field
  38. 38Complex query searchLooks at data with multiple criteria
  39. 39Wildcard charactersYou use wildcard searches in a query for data that you only know part of. For example find all the surname beginning with 's' you might write: surname LIKE '*S'
  40. 40Sorting dataResults of queries can be presented in an order e.g. Alphabetical or in numerical order . Sorts can oaks I be in ascending (a-z) or descending (z-a)
  41. 41Why sort data- easier if lists are printed as report
    - you can identify best customer by amount they have spent - sort then according to total amount spent
  42. 42if data is secure then- it cannot be destroyed
    - it cannot be accidently of maliciously altered
    - it cannot fall into the hands of unauthorised people
  43. 43Consequences for a business where data is not secure includes- loss of customers - unhappy customers go else where
    - payments for goods not being received
    Bad publicity- all buissnesses rely on a good reputation
  44. 44Number of methods used to keep data securePhysical security, oasswords, access rights ( file attributes) can be places or individual files to give, back ups
  45. 45Physical securityLock on doors
    Alarms
    Id. Cards
    Biometric systems
  46. 46Passwords- 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
  47. 47Access rights ( file attributes ) can be placed or individual files to giveNo right to access the file
    Read access ( user can view file but not alter it )
    Write access( allowing the user to alter the contents of the file )
  48. 48BackupsA back up us a second copy of the data. If a problem arises with the data file , then the back up copy is used . Back ups are:
    Saved in to a removable nedia( CD, DVD, memory sticks)
    - stored at a separate location in a locked room or fireproof safe
    Made regularly ( every day)
  49. 49Benefits of using a databaseFast access, easy to edit , validation, reports , sharing, security

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FlashCards sobre IT- Topic 8, criado por Emer Neave em 16-01-2015.
Criado por
Emer Neave · jan 2015
Atualizado
19 fev 2016
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