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Sin título
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- 1what is a database?a database is an organised collection of related data. it is possible to add, edit, manage and retrieve data from the database. the structure of the database allows data to be found and used quickly.
- 2give an example and a description of the data type; number (integer)43, a whole number(positive or negative) but no fractions.
- 3give an example and definition of the data type; number (real)435.256, any number, including whole numbers and fractions.
- 4give an example and a definition of the data type; text or stringjohn smith, letters, numbers or other characters such as punctuation marks.
- 5give an example and description of the data type; date/time4/10/10
12:15:45
any time/ date the way the time or date is displayed depends on how it is formatted. - 6give an example and a description of the date type; currency£13.55
money £ (including foreign) - 7give an example and a description of the data type; Boolean.yes
two opposing states/ true or false, yes or no. - 8give an example and description of the data type; listsred, green, blue
a list of values, sometimes called a 'drop down list' only data from the list can be entered. - 9give an example and a description of the data type; picture--------
--------
image data, from a digital camera, mobile phone, the internet, a clip art library or scanned in image. - 10give an example and a description of the data type; sounda sound or music clip
a beep from a barcode reader of a popular song. - 11give an example and a description of the data type; videoa moving picture,
a video introduction to computer game or a downloaded film/TV program - 12what is a field?a field is a single item of data within a record.
- 13what is a record?record consists of a collection of related fields.
- 14what is a file?a file (known as a table in Microsoft access) is a collection of related fields.
- 15give an example of a fieldsurname
d.o.b
selling pricing - 16give an example of a recordpupils record in a school database only has the fields related to that pupil (surname, forename, d.o.b, form etc,) and not another pupils data.
- 17give an example of a file/tablethe table of records for all pupils in the school.
- 18what is a key field?a key field uniquely identities each record. no two records are the same. aka the primary key.
- 19give an example of a key fielda pupil ID
- 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 take the form of an identity number, membership number of barcode.
- 21why do we use validation?so that date entered into a database is sensible and isn't GIGO.
- 22what is a validation rule?a validation rule check the data as it is being entered 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.
- 23give an example and a description of the validation method; range checkif test is out of 100 marks then only marks in the range of 0-100 are acceptable.
the data entered must be in a sensible range. - 24give an example and a description of the validation method; type checkif the number of rooms in a house is being recorded then only an integer ( whole number) will be accepted.
this ensures that the data type is of the correct type. - 25give an example and a description of the validation method; format/picture checkinput mask for a database would be LLN NLL eg. ME1 3BY where L is a letter N is a number.
- 26give an example and a description of the validation method; length checkif a forename is being entered it is reasonable to assume that it will be between 2 and 18 characters long.
the length of the input is checked for the number of characters used. - 27give an example and a description of the validation method; presence checkif 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.
some data has to be entered. - 28give an example and a description of the validation method; look up listif the predicted grade for an exam can only be a,b,c,d,e or u, only these inputs are allowed.
if the data entered consists of a limited a=number of possible entries then the computer can compare the entry with a list of allowed answers. - 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.
- 30what are forms used for?forms are used to make data entry more attractive and secure rather than entering data into raw tables.
- 31what is a calculated field?not all data needed in a report may be present in a database. for example a person's age is never included because it changes daily. if you want to use age in a report it must be calculated. this result is known as a calculated field.
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- Fichas sobre Sin título, creado por imy saunders el 16/01/2015.
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- imy saunders
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