Master Data Management in Games: Simplify with the Repository Pattern

Data is the foundation of any game. However, raw data on its own doesn’t have much meaning—it’s scattered and unconnected. When we organize it in a way that shows how different pieces of data relate to each other (like using classes or structs), it starts to make sense and becomes meaningful.

Repository Pattern in Game Development

The Repository Pattern is a design approach that helps separate your game’s main logic (like gameplay mechanics or business rules) from the code that manages and retrieves data. Instead of your game directly accessing databases, files, or other storage systems, a Repository acts as a middleman. It handles data storage and retrieval while keeping the core game logic focused on gameplay rather than worrying about where or how the data is stored.

This separation makes your code cleaner, easier to test, and more adaptable to changes. For example, if you decide to switch from using a local file to a database, you only need to update the repository, not the entire game logic.

Let’s take an example project:[LINK]

Understanding the Repository Pattern in Game Development

The Repository Pattern serves as an intermediary between the game’s business logic and data sources, such as databases or files. By abstracting data access, it allows developers to modify storage implementations without altering the core game logic. This separation enhances code maintainability and facilitates testing.

Implementing the Repository Pattern

Consider a shop system within a game where players can purchase items. Implementing the Repository Pattern involves:

• Defining Entities: Create classes representing game objects, like Item with properties such as ID, Name, and Price.
• Creating a Repository Interface: Establish an interface outlining data operations, including methods to retrieve, add, or remove items.
• Developing Concrete Repository Classes: Implement the interface with classes that handle data storage and retrieval, for instance, using JSON files or databases.
• Integrating with Game Logic: Utilize the repository within the game’s systems to manage data, ensuring the core logic remains decoupled from data access specifics.

Benefits of the Repository Pattern in Game Development

• Separation of Concerns: Isolates data access from game logic, leading to a more organized codebase.
• Flexibility: Allows for easy swapping of data storage methods without impacting the game’s core functionality.
• Testability: Simplifies unit testing by enabling the use of mock repositories.

Complementary Design Patterns

Incorporating other design patterns can further enhance the system:

Factory Pattern: Simplifies object creation, particularly when dealing with complex objects or multiple types.

Unit of Work Pattern: Manages transactions across repositories, ensuring consistency during operations like purchasing items.

Features

Shop System:

• Displays a list of purchasable items with their names, prices, and purchase buttons.
• Updates player’s money dynamically after each purchase.
• Prevents purchases when funds are insufficient.

Repository Pattern:

• Encapsulates data access to maintain separation of concerns.
• Handles item loading from JSON and makes the system testable.

Unit of Work Pattern:

• Coordinates transactions across repositories for consistency.
• Ensures updates to inventory and wallet happen together.

JSON Data Storage:

Item details are stored in a JSON file (ItemData.json), making it easy to modify or expand.

Technologies Used

• TextMeshPro for polished UI elements
• Unity Engine (6000.0.25f1)
• C# Scripting
• JSON for Data Storage

Project Structure

Now Let’s go through each script,

1. Item.cs Defines the structure for an Item in the game. Each item has an ID, Name, and Price. It includes a constructor to initialize these properties when creating an item.
2. Player.cs Represents the player in the game. The Player class has a Name, Money, and an Inventory to store purchased items. A constructor is included to initialize the player’s name and starting money.
3. GameData.cs Stores a collection of Item objects in a list. It serves as the container for all game items and can be used to load or save data related to the items.
4. DataContext.cs An abstract class that acts as the base for data handling. It contains a GameData object, defines abstract methods for loading and saving data, and provides a method to retrieve the list of items (Set()).
5. JsonDataContext.cs Implements DataContext to handle data using JSON files. It:
   • Loads item data from a JSON file into the game.
   • Saves current game data back into the JSON file. This class makes it easy to persist game data between sessions.
6. Repository.cs Acts as a middle layer between the data and the game logic. It:
   • Retrieves all items from the data source.
   • Gets the price of a specific item by its ID.
   • Adds or deletes items.
   • Saves changes back to the data source. The Repository keeps the data management clean and organized.
7. PopulateShop.cs Handles the game’s shop system by dynamically creating UI tiles for each available item. It:
   • Displays the item’s name and price.
   • Lets the player buy items if they have enough money. The script also updates the UI after each purchase and ensures the data is saved correctly.
8. Items.cs A simple subclass of Repository to represent the collection of items managed by the shop system. It inherits all the functionality of the Repository.
9. ItemsData.json The JSON file contains a list of items available in the shop system. Each item has three properties:
   • ID: A unique identifier for the item.
   • Name: The name of the item (e.g., Sword, Shield).
   • Price: The cost of the item in the game. This file is used to store item details, which are loaded into the game at runtime. It is easy to edit or expand, allowing new items to be added without modifying the code.

game development, managing data efficiently is crucial for creating scalable and maintainable systems. The Repository Pattern is a design approach that separates the game’s core logic from data access mechanisms, promoting cleaner code and adaptability.

Conclusion

Applying the Repository Pattern in game development facilitates efficient data management and contributes to a scalable and maintainable architecture. By decoupling data access from game logic, developers can focus on enhancing gameplay experiences without being burdened by data handling complexities.

In conclusion, the Repository Pattern and Unit of Work Pattern provide a powerful framework for structuring game systems by separating concerns and maintaining data consistency. In our example project, we’ve used these patterns to build a maintainable and testable shop system that dynamically loads and saves data while ensuring smooth and consistent gameplay. This approach improves code quality and simplifies future expansions and modifications. To get more information follow our Social Media Such as Linkedin & Facebook

Cheers!