Dynamic Finders¶

Dynamic finders in ActiveRecord provide a convenient way to query records from a database table based on attribute values without having to write custom SQL queries. These dynamic finders generate SQL queries dynamically based on the attribute you specify. They follow a specific naming convention such as find_by_attribute, find_or_initialize_by_attribute, and so on.

Basic Usage¶

The basic syntax for dynamic finders is as follows:

find_by_attribute(value): Find the first record with the specified attribute value.

Here's how you can use dynamic finders:

// Find the first user with the name "John"
$user = User::find_by_name('John');

// Find the first product with the price of 50.00
$product = Product::find_by_price(50.00);

Advanced Usage¶

You can also chain multiple attribute conditions using dynamic finders for more complex queries:

// Find the first user with the name "John" and the role "admin"
$user = User::find_by_name_and_role('John', 'admin');

// Find the first product with the name "Product Name" and price of 50.00
$product = Product::find_by_name_and_price('Product Name', 50.00);

Limitations¶

While dynamic finders are convenient for simple queries, they may have limitations for more complex queries that involve joins or subqueries. In such cases, you may need to use custom SQL queries or ActiveRecord's query-building methods.

Error Handling¶

It's important to note that dynamic finders return null when no records match the specified criteria. Therefore, it's a good practice to check the result for null to handle cases where no record is found:

$user = User::find_by_email('nonexistent@example.com');

if ($user) {
    // Record found
} else {
    // Record not found
}