Laravel Relationship Recipes: Exploring the whereRelation Method

Laravel Relationship Recipes: Exploring the whereRelation Method

Welcome to the first part of our Laravel Relationship Recipes series! In this series, we'll explore various methods in Laravel Eloquent relationships to simplify your application development.

Understanding the Scenario

Imagine you're building a financial application like a portfolio tracker. You have two main models:

1. Stock: Represents a company's stock with attributes like ticker symbol and current price.
2. Holding: Represents the holdings in portfolios, with attributes such as invested capital and market value.

Each Holding belongs to a Stock, and a Stock can have many Holdings.

Introducing the whereRelation Method

Today, we'll dive into the whereRelation method, a handy tool for querying related models efficiently.

Let's say you want to retrieve all holdings for a specific company, like Apple (AAPL). You can achieve this with a simple join query, like so:

$appleHoldings = Holding::select('holdings.*')
    ->leftJoin('stocks', 'stocks.id', 'holdings.stock_id')
    ->where('stocks.ticker', 'AAPL')
    ->get();

However, Laravel provides a more elegant solution using the whereRelation method. Here's how you can use it:

$appleHoldings = Holding::whereRelation('stock', 'ticker', 'AAPL')
    ->get();

Understanding the Method

The whereRelation method reads like this: "give me every Holding where the Stock relation's ticker column is equal to AAPL." Under the hood, Laravel translates this into an EXISTS query, making it a more efficient way to query related models.

Conclusion

The whereRelation method in Laravel Eloquent relationships offers a cleaner and more expressive way to query related models. By leveraging this method, you can simplify your code and improve the readability of your queries.

Stay tuned for more Laravel Relationship Recipes in this series, where we'll explore other useful methods for working with Eloquent relationships!