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Chapter 19
Data Entry Procedures
Jerry Post
Copyright © 1997
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Goals
 Collect accurate data.
 Effective data coding.
 Efficient data capture and
entry.
 Data validation.
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Data Encoding
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 Codes to conceal
S  Simple ID Numbers
 Sequential
 e.g., hide prices
T
 Easy to create.
 Simple substitution ciphers
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 Problems if mistype by one
(substitute one letter for a
M
number.
number, etc.)
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 Alphabetic
 Codes to provide information
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 Hide the count.
 Contain additional
information.
 Classification codes
 e.g., M=male, F=female
 Block sequence
 Sequential numbers
assigned to categories.
 100-199 = spreadsheet
 200-299 = database
 Categories (significant digit)





e.g., 2023954010
Dept. 202
Prod. 395
Color
40
Size
10
 Mnemonic codes
 e.g., airports: STL, LAX,
SLC
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Guidelines for Creating Codes
 Be concise.
 Keep the codes stable.
 Assure that codes are
unique.
 Allow codes to be sortable.
 Avoid confusing codes.
 Keep codes uniform.
 Allow for modification an
expansion.
 Make codes meaningful.
 Add check-digits.
 Bad examples:




20927365123452
170AB, QQ9882, 2O008
Apr495, Mar396, Dec1595
1lS52ZO0
 Better examples:
 125, 998, 253
 170AB, 982QQ, 291QB
 950304, 960303, 951215
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Effective and Efficient Data Capture
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 Entry options
S  Decide what to capture.
 Optical character
T  Let the computer look up
recognition (OCR).
data.
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 Magnetic ink character
M  Let the computer do
recognition (MICR).
computations.
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 Mark-sense forms.
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 Avoid bottlenecks and extra
steps.
 Start with a good form
(especially drop-down
boxes).
 Avoid batch data-entry.
 Collect data as close to the
source as possible.
 Punch-out forms.
 Bar codes.
 On-line/customer entry
(Web site).
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Data Validation
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S  Validating input transactions  Validating input data
(errors to avoid).
 Test for missing data.
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 Submitting the wrong data.
 Test for correct field length.
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 Submitting data by an
 Test for class or
M
unauthorized person.
composition.
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 Asking the system to
 Test for range or
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perform an unacceptable
function.
reasonableness.
 Test for invalid values.
 Test for comparison with
stored data.
 Design self-validating codes
(check digits).
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Check Digits
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S  Add a digit to the end of the
Code: 54823
code
that
is
based
on
the
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Weights (1 x 3), Modulus: 10
earlier digits.
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5*1 = 5
4*3 = 12
M  Need weights for each
position.
8*1 = 8
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 Catch transposition.
 Catch double errors.
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 Strongest is Cyclic
Redundancy Check (CRC).
 Fits a polynomial to data.
 Catches most common
errors.
 Algorithm is in CS books.
2*3 = 6
3*1 = 3
Add: 5 + 12 + 8 + 6 + 3 = 34
Get modulus:
34/10 = 3, remainder = 4
(Optional: 10 - 4 = 6)
New code: 548236
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