Flashcards
ICT Ch.2
Cards in this deck (29)
- 1data source errordata source providers provide incorrect data
- 2transcription errordata is read/typed incorrectly
- 3transposition errortwo consecutive digits are swapped
- 4GIGOGarbage-In-Garbage-Out
- 5types of data controldata validation
data verification - 6field presence checkensure the necessary fields are present
- 7field length checkensure the data has the correct number of character/ digits
- 8range checkensure the data value is within a pre-determind range
- 9fixed value checkensure the data is same as one of the pre-defined values
- 10format checkensure the form of data follows some known pattern
- 11type checkensure the data types are correct
- 12check digitscheck the validity of data
e.g. parity check - 13calculate ISBN/ ID card numberweighted sum= ...
... ... (remainder)
check digit= 11- ...
the ISBN is valid/invalid - 14data verificationinput data twice
double data entry - 15input data twicean operator inputs the data twice
allows the computer to check the second entry against the first one - 16double data entrytwo operators enter the same data into two different files
the computer compare the two files and report the discrepancies between - 17data hierarchyfield
record
table
database - 18key fieldkey field is a field that can be used to uniquely identify one specific record from others
- 19DBMSDatabase Management System
- 20use of DBMSmanage the database structure
store, organize and retrieve data in a database - 21basic function of DBMScreate tables
modify tables
delete tables
add new records
delete existing records
modify existing records
browse records - 22filterallows users to specify a filtering condition
and hide records temporarily - 23sortchange the order of records according to the values of field(s)
- 24indexis a small file containing a number of index key
arrange the order of records according to the index - 25data entry formsan interface for adding /modifying records
- 26query formsan interface for extracting and displaying the records which match the condition
- 27reportsdisplay results on screen/
produce hard copies in defined format - 28sequential file access modedata records are stored one by one along a strip
e.g. magnetic tape
used for back up/ recovering - 29direct file access modee.g. hard disk, floppy disk, optical disk
read/write data to the location directly
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- F.4 ICT Flashcards on ICT Ch.2, created by chiu serena on 29/12/2015.
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- chiu serena
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