Introduction
Newtronics Plc. is a company which sells electronic parts (diodes, transistors,
IC's, LED's thermostats etc.) and goods. Currently, the company is being
computerised and you have been retained to write one of the programs required.
Information about the parts and goods held in stock by the company is
contained in two files; the Stock Master File and the Supplier Master
File. Adjustments to stock, such as selling an item or receiving new
supplies into stock are made on-line by an update program written by others.
File maintenance (Insertion, Deletion and Adjusting of records) to the
master files will be achieved by applying a file of transaction records
to them at the end of each day. Your task is to write the program which
will take the Transaction file and apply it to the master files.
The Transaction
File
The Transaction File is a unsorted, unvalidated file containing a number
of different types of transaction record. Each transaction record type
is identified by a transaction type code in the first character position.
The following transaction types have been identified :-
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|
Trans
Type
|
Description
|
|
1
|
Delete Stock Record
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|
2
|
Insert Stock Record
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3
|
Adjust Reorder Level
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4
|
Adjust Reorder Qty
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5
|
Adjust Price
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6
|
Delete Supplier
Record
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7
|
Insert Supplier
Record
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|
Transaction Record Descriptions
Descriptions of the different types of transaction record are shown
below.
Delete Stock Record
|
FieldName
|
Type
|
Length
|
Format
|
|
Transaction-Type
|
Numeric
|
1
|
Value 1
|
|
Stock-Number
|
Character
|
7
|
9999999
|
Insert Stock Record
|
FieldName
|
Type
|
Length
|
Format
|
|
Transaction-Type
|
Numeric
|
1
|
Value 2
|
|
Stock-Number
|
Numeric
|
7
|
9999999
|
|
Qty-In-Stock
|
Numeric
|
5
|
99999
|
|
Price
|
Numeric
|
6
|
9999.99
|
|
Reorder-Level
|
Numeric
|
3
|
999
|
|
Reorder-Qty
|
Numeric
|
5
|
99999
|
|
Supplier-Number
|
Character
|
4
|
X999
|
Adjust Reorder Level
|
FieldName
|
Type
|
Length
|
Format
|
|
Transaction-Type
|
Numeric
|
1
|
Value 3
|
|
Stock-Number
|
Numeric
|
7
|
9999999
|
|
Reorder-Level
|
Numeric
|
3
|
999
|
Adjust Reorder Qty
|
FieldName
|
Type
|
Length
|
Format
|
|
Transaction-Type
|
Numeric
|
1
|
Value 4
|
|
Stock-Number
|
Numeric
|
7
|
9999999
|
|
Reorder-Qty
|
Numeric
|
5
|
99999
|
Adjust Price
|
FieldName
|
Type
|
Length
|
Format
|
|
Transaction-Type
|
Numeric
|
1
|
Value 5
|
|
Stock-Number
|
Numeric
|
7
|
9999999
|
|
Price
|
Numeric
|
6
|
9999.99
|
Delete Supplier Record
|
FieldName
|
Type
|
Length
|
Format
|
|
Transaction-Type
|
Numeric
|
1
|
Value 6
|
|
Supplier-Number
|
Character
|
4
|
X999
|
Insert Supplier Record
|
FieldName
|
Type
|
Length
|
Format
|
|
Transaction-Type
|
9
|
1
|
Value 7
|
|
Supplier-Number
|
X
|
4
|
X999
|
|
Supplier-Name
|
X
|
20
|
-
|
|
Supplier-Address
|
X
|
35
|
-
|
The Master Files
The Stock Master File
The Stock Master File is an Indexed file with the following record description.
|
FieldName
|
Key
type
|
Type
|
Length
|
Format
|
|
StockNumber
|
Primary
|
9
|
7
|
9999999
|
|
QtyInStock
|
|
9
|
5
|
99999
|
|
Price
|
|
9
|
6
|
9999.99
|
|
ReorderLevel
|
|
9
|
3
|
999
|
|
ReorderQty
|
|
9
|
5
|
99999
|
|
SupplierNumber
|
ALT with Duplicates
|
X
|
4
|
X999
|
The Supplier Master File
The Supplier Master File is an Indexed file with the following record
description.
|
FieldName
|
Key
type
|
Type
|
Length
|
Format
|
|
SupplierNumber
|
Primary
|
X
|
4
|
X999
|
|
SupplierName
|
ALT with Duplicates
|
X
|
20
|
-
|
|
SupplierAddress
|
|
X
|
40
|
-
|
The Stock Archive File
The Stock Archive File is a sequential file with the following record
description.
|
FieldName
|
Type
|
Length
|
Format
|
|
StockNumber
|
9
|
7
|
9999999
|
|
QtyInStock
|
9
|
5
|
99999
|
|
Price
|
9
|
6
|
9999.99
|
|
ReorderLevel
|
9
|
3
|
999
|
|
ReorderQty
|
9
|
5
|
99999
|
|
SupplierNumber
|
X
|
4
|
X999
|
The Error
File
The Error File is an unordered Sequential File. Records in the Error
File have the same format as those in the Transaction File.
Validation Requirements
For the sake of efficiency, the Transaction File should be sorted on
ascending TransactionType within ascending StockNumber before the records
are applied to the Master Files. Some of the validation can be done before
the Sort executes and should be done in an Input Procedure. The rest
of the processing should be done in an Output Procedure.
When an error occurs the transaction record should be written to an Error
File. Records in the Error File have the same format as those in the
Transaction File. As soon as an error is found in a transaction record,
the record should be written to the Error File and no further checking
should be done.
General Validation
Ensure that the Transaction-Type is numeric and within range 1 to
7.
General Transaction Record Validation
Ensure that the Stock-Number is numeric and that the check digit
is correct (implement check digit validation as a contained sub-program
with no Global data).
Delete Stock Record Special Validation
Ensure that the record does exist in the master file and that the
Qty-In-Stock in the master file record is zero. If all is OK write
the Stock Master File record to the Stock Archive File and then delete
the master file record.
Insert Stock Record Special Validation
Ensure that the record does not already exist and that there is
a corresponding record in the Supplier Master File. Ensure that the
Qty-In-Stock, Price, Reorder-Level and Reorder-Qty fields are numeric
and initialized to zero. If all is OK insert the record.
Adjust Special Validation
Ensure that the record does exist in the master file. If all is
OK update the master record.
Insert Supplier Record Special Validation
Ensure that the record does not already exist. If all is OK then
insert the record.
Delete Supplier Record Special Validation
Ensure that the record does exist and that there are no records
with this SupplierNumber left in the Stock Master File. If all is OK
delete the master file record.
Validating
The StockNumber Check Digit
The StockNumber is a seven digit number with the seventh (rightmost)
digit being the calculated check digit. Each of the real digits ( the
first six) has a weight associated with it. Starting from the leftmost
digit the weights are as follows:-
D1 = 7, D2 = 6, D3 = 5, D4 = 4, D5 = 3, D6 =
2.
In the StockNumber the check digit modulus is 11. The check digit can
be calculated as follows:-
Multiply each digit by its weight and add the results together.
Divide the sum of the results by the modulus 11 and subtract the remainder
from the modulus. The result is the check digit. The check digit in
your student number is calculated in exactly the same way so any valid
student number will be a valid StockNumber.
Here is an example:-
StockNumber = 7944454
Real Number = 794445
Check Digit = 4
Digit D1 D2 D3 D4 D5 D6
* * * * * *
Weight 7 6 5 4 3 2
---- ---- ---- ---- ---- ----
Result R1 + R2 + R3 + R4 + R5 + R6 = Sum Of Results
Digit 7 9 4 4 4 5
* * * * * *
Weight 7 6 5 4 3 2
---- ---- ---- ---- ---- ----
Result 49 + 54 + 20 + 16 + 12 + 10 = 161
| 161/11 = 7 |
Divide the Sum Of Results by Modulus
11 giving Remainder.
|
| 11-7 = 4 |
Subtract the
Remainder from the Modulus
giving CheckDigit.
StockNumbers that yield check digits of 10 and 11 are invalid StockNumbers. |
So the check digit is 4.
If you only want to discover whether a check digit is correct or not
then get the Sum Of Results
as above, add the check digit to it and divide by 11. If there is no
remainder then the check digit is correct.
Copyright Notice
This COBOL project specification is the
copyright property of Michael Coughlan. You have permission to use this
material for your own personal use but you may not reproduce it in any
published work without written permission from the author.
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