In this case study, we will build a simple Inventory Management System using RPG. This project will help you understand how to apply the concepts learned in previous modules to a real-world application. We will cover the following steps:
- Requirements Analysis
- Database Design
- Program Design
- Implementation
- Testing
- Requirements Analysis
Before we start coding, we need to understand the requirements of our Inventory Management System. Here are the key features we want to implement:
- Add New Items: Ability to add new items to the inventory.
- Update Item Information: Ability to update existing item details.
- Delete Items: Ability to remove items from the inventory.
- View Inventory: Ability to view all items in the inventory.
- Database Design
We will use a simple database table to store our inventory items. The table will have the following structure:
| Field Name | Data Type | Description |
|---|---|---|
| ITEM_ID | CHAR(10) | Unique identifier for the item |
| ITEM_NAME | CHAR(50) | Name of the item |
| QUANTITY | INT | Quantity of the item in stock |
| PRICE | DEC(7,2) | Price of the item |
- Program Design
We will create a modular program with the following procedures:
- AddItem: Adds a new item to the inventory.
- UpdateItem: Updates the details of an existing item.
- DeleteItem: Deletes an item from the inventory.
- ViewInventory: Displays all items in the inventory.
- Implementation
4.1 AddItem Procedure
// AddItem Procedure
P AddItem B
D AddItem PI
D itemId CHAR(10)
D itemName CHAR(50)
D quantity INT(10)
D price DEC(7,2)
D sqlStmt S CHAR(200)
/free
sqlStmt = 'INSERT INTO INVENTORY (ITEM_ID, ITEM_NAME, QUANTITY, PRICE) ' +
'VALUES (' + itemId + ', ' + itemName + ', ' + %char(quantity) + ', ' + %char(price) + ')';
EXEC SQL EXECUTE IMMEDIATE :sqlStmt;
/end-free
P AddItem E4.2 UpdateItem Procedure
// UpdateItem Procedure
P UpdateItem B
D UpdateItem PI
D itemId CHAR(10)
D itemName CHAR(50)
D quantity INT(10)
D price DEC(7,2)
D sqlStmt S CHAR(200)
/free
sqlStmt = 'UPDATE INVENTORY SET ITEM_NAME = ' + itemName + ', QUANTITY = ' + %char(quantity) + ', PRICE = ' + %char(price) +
' WHERE ITEM_ID = ' + itemId;
EXEC SQL EXECUTE IMMEDIATE :sqlStmt;
/end-free
P UpdateItem E4.3 DeleteItem Procedure
// DeleteItem Procedure
P DeleteItem B
D DeleteItem PI
D itemId CHAR(10)
D sqlStmt S CHAR(200)
/free
sqlStmt = 'DELETE FROM INVENTORY WHERE ITEM_ID = ' + itemId;
EXEC SQL EXECUTE IMMEDIATE :sqlStmt;
/end-free
P DeleteItem E4.4 ViewInventory Procedure
// ViewInventory Procedure
P ViewInventory B
D ViewInventory PI
D sqlStmt S CHAR(200)
D itemId S CHAR(10)
D itemName S CHAR(50)
D quantity S INT(10)
D price S DEC(7,2)
/free
sqlStmt = 'SELECT ITEM_ID, ITEM_NAME, QUANTITY, PRICE FROM INVENTORY';
EXEC SQL DECLARE C1 CURSOR FOR :sqlStmt;
EXEC SQL OPEN C1;
DOU SQLCOD <> 0;
EXEC SQL FETCH C1 INTO :itemId, :itemName, :quantity, :price;
if SQLCOD = 0;
dsply ('Item ID: ' + itemId + ' Name: ' + itemName + ' Quantity: ' + %char(quantity) + ' Price: ' + %char(price));
endif;
ENDDO;
EXEC SQL CLOSE C1;
/end-free
P ViewInventory E
- Testing
To ensure our Inventory Management System works correctly, we need to test each procedure:
- AddItem: Test by adding new items and verifying they appear in the database.
- UpdateItem: Test by updating existing items and verifying the changes.
- DeleteItem: Test by deleting items and ensuring they are removed from the database.
- ViewInventory: Test by viewing the inventory and ensuring all items are displayed correctly.
Conclusion
In this case study, we designed and implemented a simple Inventory Management System using RPG. We covered the entire process from requirements analysis to testing. This project demonstrates how to apply RPG programming concepts to build a functional application. In the next section, we will explore another real-world application to further solidify your understanding of RPG programming.
RPG Programming Course
Module 1: Introduction to RPG Programming
Module 2: Core Concepts
Module 3: Working with Data
Module 4: Advanced Programming Techniques
Module 5: RPG IV and Beyond
Module 6: Integrating RPG with Modern Technologies
Module 7: Real-World Applications
- Building a Simple Application
- Case Study: Inventory Management System
- Case Study: Payroll System
- Best Practices and Code Review