CHAPTER 5 Flashcards
(54 cards)
Data types
numeric
- integer
- decimal
currency
text
date
Boolean
advantages of flat file database
all records are stored in one table
easier to understand
easier to sort and filter data
easier to set up
check to minimize errors
validation and verification
validation
make sure data entered is logic
prevents: illogical entries
does not prevent: incorrect logic entries
done by: computer
verification
make sure data entered is: identical to data source
prevents: copying
does not prevent: errors in data source
done by: user
verification checks
double data entry: user enters data twice and computer compares the two entries to make sure they are identical
visual check: user visually compares data entered with data source to make sure they are identical
proof-reading is not verification check
reading the document after typing to check for speeling,grammar,punctuation mistakes
range check
description:
make sure numbers entered are within specific limits
examples:
numeric fields
data fields
in practical
between 0 and 100
length check
description: make sure the exact correct number of characters have been entered; not more and not less
examples: telephone no
candidate no
Centre no
format check
make sure letters,numbers,specific symbols are in their specified positions
example:
Centre number
look up check
make sure data entered is one of specified options
example:
gender M or F
presence check
make sure the field is not left blank
key fields
in practical:
NOT NULL
type/character check
type check allows only numbers to be entered character checks allows certain characters
example
price can only contain numbers
email address can only contain certain characters
check digit
certain calculation performed in the numbers of a barcode and the result must be equal to the check digit
example
barcode
formula vs function
formula:
can be simple calculations
can be easily typed by suer
can contain a function
function:
built into the software
have a pre-defined name
naming cells
easily referring to cells
simplifies formulas
easily to refer to cells without using cell references
don’t have to set absolute cell manually
absolute cell reference $A$2
when replicated the cell reference will not change.
absolute file path
displays file name and path means files are not saved in same folder
will only work on one computer as other computers will not have the same file path
web development layers
content layer (htm) images,tables,text,hyperlinks
presentation layer colours,fonts,borders
behavior layer interaction of website
relative cell reference (A2)
when replicated the cell reference will change
relative file path
displays only file name
means all files are saved in same folder
files should be saved in one folder to be ready for publishing the website
anchor
a position on the webpage that a hyperlink will point to
bookmark
saved shortcut to direct the user to certain website
hyperlink
a link from text or image to redirect the user to another position on the same page, another webpage, an email.
