771478
Data
Handling
- Data Validation: Checks that
data entered is reasonable
but cannot check it is correct.
- Range check: It checks the length of the
data entered is within a certain range.
- Presence check: Makes sure data
has been entered in a cell.
- Format check: Makes sure data
has been entered in the correct
format e.g. date of birth.
- Length check: It checks
the data isn't to short or
long.
- Check Digit: It puts digits into a
calculation to check they are valid
commonly used on barcodes.
- Lookup Check: It checks
the data is correct from a
table stored else where.
- Range check: It checks the length of the
data entered is within a certain range.
- Data Types
- Text: stores both
letters and numbers.
- Integer: Stores whole
numbers that don't begin
with zero.
- Real Number: Stores only
decimal numbers however
they cant start with zero.
- Date: Is used to store date in the correct format
however their is a format choice. Short date e.g.
03/09/2020 or long date e.g. 3rd September 2020
- Boolean: offers a choice of
one or the other. Yes/no.
- List: Offers a few select items
on a list reducing mistake.
- Text: stores both
letters and numbers.
- Databases
- Relational database
- It links several tables together
saving on data duplication saving
on mistakes but also time
- Can be used to enforce
rules by brining up error
messages when certain
rules are broken.
- Easy to run a query.
- It links several tables together
saving on data duplication saving
on mistakes but also time
- Flat file database
- One large database holding all the
information means some data may be
keyed twice
- Difficult to read and use
day to day
- Difficult to run a query on a large table.
- More prone to mistakes due to confusing layout.
- One large database holding all the
information means some data may be
keyed twice
- Relational database
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