Which model does the answer use as the system-level process (behaviour) model?

Data Flow Diagram (context plus level-1)

Which are treated as external entities in the model?

Departments, publishers, the receiving department and students

Inventory and Sales data stores

Purchase order and sales receipt

According to the stated assumptions, how is the order quantity found?

Projected enrolment minus books already in stock

How does the D3 Inventory store link the processes?

It is read by 2.0 to decide order size, increased by 3.0 on receipt and reduced by 4.0 on sale

It is written only by the departments

What happens in the model when the packing slip is not verified (missing or damaged books)?

The stock update in 3.0 stops and the problem is reported back to the publisher

2069 Chaitra · 7 marks

Book store process model

Short answer

Assumptions: system is book inventory system; departments, publishers, receiving department, students are external entities; departments send master list per semester; order quantity = projected enrollment minus stock; receiving verifies packing slip; students pay at counter; stock updated on receipt/sale. Context diagram shows external entities and data flows. Level-1 DFD processes: prepare master list, generate purchase order, receive/verify books, sell books. Data stores: book master list, purchase orders, inventory, sales.

Bhrantipur Book Store is popular among engineering students within the city of Bandhapur, as they have good reputation of making available of the reference books very efficiently through their books inventory system. Their reputation is mainly because of their close coordination with engineering schools. The various departments submit initial data about courses, instructors, textbooks and projected enrollments to the book store on a reference-book master list. The book store then generates a purchase order, which is sent to publishing companies that supplies the books. Book orders arrive at the bookstore accompanied by a packing slip, which is checked and verified by the receiving departments of engineering schools. When they pay for the books, the students are given a sales receipt. Following the details of the book order, inventory and sales processes prepare a system level process (behavior) model diagram for above scenario with clear statement of any assumptions that you have made.

A system-level process (behaviour) model for this scenario is best shown as a Data Flow Diagram: a context diagram for the whole store and a level-1 DFD for the book order, inventory and sales processes.

Assumptions

The system is the book store's book inventory system; departments, publishers, the receiving department and students are outside it (external entities).
Each department sends one reference-book master list per semester with course, instructor, textbook and projected enrolment data.
Order quantity = projected enrolment − books already in stock (read from inventory).
The receiving department checks the packing slip against the purchase order and returns a verified slip (or a list of discrepancies).
Students pay at the counter (cash or card); payment details are not modelled further.
Stock is increased when verified books are received and decreased when books are sold.

Context diagram (level 0)

                course, instructor,
 +-------------+ textbook, enrolment  +------------+
 | Departments |--------------------->|            |
 +-------------+                      |            |
                    purchase order    |    Book    |
 +-------------+<---------------------| inventory  |
 | Publishers  |--------------------->|   system   |
 +-------------+ books + packing slip |            |
                                      |            |
 +-------------+  packing slip        |            |
 | Receiving   |<---------------------|            |
 | department  |--------------------->|            |
 +-------------+  verified slip       |            |
                                      |            |
 +-------------+  payment             |            |
 |  Students   |--------------------->|            |
 |             |<---------------------|            |
 +-------------+  sales receipt       +------------+

Level-1 DFD

+-------------+
| Departments |
+-------------+
      | course, instructor, textbook,
      | projected enrolment
      v
+------------------+        ======================
| 1.0 Prepare      |------->  D1 Book master list
|   master list    |        ======================
+------------------+                  |
                                      | books needed
      +-------------------------------+
      v
+------------------+  stock   ======================
| 2.0 Generate     |<-------    D3 Inventory
|  purchase order  |          ======================
|                  |  PO      ======================
|                  |------->    D2 Purchase orders
+------------------+          ======================
      | purchase order
      v
+-------------+
| Publishers  |
+-------------+
      | books + packing slip
      v
+------------------+ slip    +-------------+
| 3.0 Receive and  |-------->| Receiving   |
|   verify books   |<--------| department  |
+------------------+verified +-------------+
      | quantity received
      | (PO read from D2, stock added to D3)
      v
+------------------+ receipt +-------------+
| 4.0 Sell books   |-------->|  Students   |
|                  |<--------|             |
+------------------+ payment +-------------+
      | sale record --> D4 Sales
      | quantity sold --> D3 Inventory (reduce)

Description of processes

Process	Input	Output	Data stores
1.0 Prepare master list	Course, instructor, textbook, enrolment data	Master list entries	Writes D1
2.0 Generate purchase order	Books needed, current stock	Purchase order to publisher	Reads D1, D3; writes D2
3.0 Receive and verify books	Books + packing slip, verified slip	Stock update	Reads D2; updates D3
4.0 Sell books	Book request, payment	Sales receipt	Writes D4; updates D3

Data stores

D1 Book master list – course, instructor, title, author, required quantity.
D2 Purchase orders – PO number, publisher, titles, quantities, status.
D3 Inventory – ISBN, title, quantity in stock, price.
D4 Sales – receipt number, date, student, books sold, amount.

How the model shows behaviour

The flows run in business order: master list → purchase order → delivery and verification → sale. This order is the system's behaviour over one semester.
Inventory (D3) links all processes: 2.0 reads it to decide how many books to order, 3.0 adds stock and 4.0 reduces it.
An unverified packing slip (missing or damaged books) stops the stock update in 3.0 and is reported back to the publisher; this exception is part of the assumed behaviour.

The model covers the three main business processes: ordering (1.0, 2.0), inventory (3.0 and the D3 updates) and sales (4.0).

✓ Answer checked by Claude Sonnet 5.5

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