Purchase Order Management Application

Welcome to the coding exercise!
This application is a Purchase Order Management System built with .NET 9 (Web API), Angular, and SQL Database (Code First).

It allows procurement staff to manage purchase orders (POs) with features like listing, filtering, sorting, pagination, add/edit/delete.

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📦 Overview

A full‑stack Purchase Order Management application built to demonstrate real‑world engineering practices using .NET Core (backend), Angular (frontend), and SQL (relational database). The project emphasizes a clean, modular architecture, SOLID principles, testability, and maintainability.

This README explains the project purpose, how to run it locally, the architecture and design decisions, and How to evaluate the work.

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🏗️ Architecture & Design Decisions

• Clean Architecture: Separation of concerns into layers (API, Application / Use Cases, Domain, Infrastructure) to keep core domain independent of frameworks
• SOLID Principles:
  • Single Responsibility: Controllers are small, services-focused
  • Dependency Inversion: Use interfaces and DI
  • Open/Closed: Services are extendable without modifying existing code
  • Liskov Substitution & Interface Segregation applied where relevant
• Repository & Unit of Work: Abstractions for data access for easier testing and flexibility
• DTOs: Used for API surface and mapping to domain entities to decouple internal models
• Validation: Centralized request validation using Data Annotations
• Error Handling: Global exception middleware to return consistent error responses

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🌐 Example API Endpoints

• GET /api/purchase-orders — list purchase orders
• GET /api/purchase-orders/{id} — get single order
• POST /api/purchase-orders — create order (payload: supplier, date, lines)
• PUT /api/purchase-orders/{id} — update order
• DELETE /api/purchase-orders/{id} — delete order

Request/response shapes are described in the DTOs file.

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🚀 Features

1. List of Purchase Orders

• Display purchase orders in a tabular view.
• Support filtering (by supplier, status, or date range).
• Support sorting (by PO number, order date, total amount).
• Support pagination for large datasets.
• Display reports with lazy loading

2. Manage Purchase Orders

• Create new purchase orders.
• Update existing purchase orders.
• Delete purchase orders.

3. Purchase Order Fields

• PO Number (unique identifier)
• Description
• Supplier Name
• Order Date
• Delivery Date
• Total Amount
• Status (Draft / Approved / Shipped / Completed / Cancelled)

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📌 Assumptions

• PO Number must always be unique.
• Status can only be one of: Draft, Approved, Shipped, Completed, or Cancelled.
• Total Amount is always stored and displayed with two decimal places.

Filtering Assumptions

• Supplier filtering uses an exact match (case-insensitive).
• Status filtering uses the predefined POStatus enum values.
• Date range filtering uses inclusive range (>= startDate and <= endDate).

Sorting Assumptions

• PO Number, Order Date, or Total Amount can apply sorting.
• Sorting defaults to ascending order unless explicitly requested as descending.
• Columns can be sorted at a time.

Pagination Assumptions

• Default page size is 10.
• The client can change the page size.

Performance Assumption

• Filtering, sorting, and pagination are implemented to handle large datasets.

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⚙️ Tech Stack

• Backend: .NET 9 Web API
• Frontend: Angular 20+
• Database: MySQL Server (EF Core Code First)
• ORM: Entity Framework Core

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🛠️ Setup Instructions

1. Install .NET 9

• Download and install .NET 9 SDK from the official site:
  https://dotnet.microsoft.com/en-us/download/dotnet/9.0
• Verify installation:

dotnet --version

2. Install Node.js and Angular (20)

• Install Node.js (which includes npm)

  1. Go to https://nodejs.org
  2. Download the LTS version (recommended) or Node 20+ for Angular 20
  3. Run the installer and follow the prompts

• Verify Node.js installation:

node -v
npm -v
npm install -g @angular/cli

2. Clone Repository

git clone https://github.com/your-username/purchase-order-management.git
cd Purchase-Order-Management-FullStack

3. Start XAMPP / Install

• Install XAMPP (if not already installed).
• Start Apache and MySQL services.
• Make sure your MySQL connection string in appsettings.json matches your local credentials.

Example:

"ConnectionStrings": {
  "DefaultConnection": "server=localhost;database=PurchaseOrderDB;user=root;password=;"
}

4. Backend Setup

1. Navigate to the backend folder and build the project:

cd backend
dotnet build

2. Run initial Entity Framework migrations to create the database schema

cd PurchaseOrderManagement.WebApi
dotnet ef migrations add InitialCreate --project ../PurchaseOrderManagement.Infrastructure --startup-project .
dotnet ef database update --project ../PurchaseOrderManagement.Infrastructure --startup-project .

3. Run Backend Web Api

dotnet run

5. Frontend Setup

1. Navigate to the frontend folder and build the project (got to the root):

cd frontend
cd purchase-order

2. Install dependencies and start the application:

npm i
npm start

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Contact

• Author: Chethiya Bandara Herath
• Email: chethiyabandaraherath@gmail.com
• Mobile: +94757120896