Laravel Eloquent关联层级转换：将Person层级转为En层级

Got it, let's tackle this structure reversal with your existing Eloquent collections. Here's how you can flip the hierarchy so you can access properties like $en->accounts[0]->person->p1 seamlessly.

Step 1: Ensure Eager Loading (Avoid N+1 Queries) #

First, make sure your $persons collection has all necessary relationships preloaded to prevent unnecessary database hits. If you haven't already, fetch the collection with nested eager loading:

$persons = Person::with('accounts.en')->get();

This loads all related Account and En models upfront, making the rest of the process efficient.

Step 2: Reorganize the Collection Hierarchy #

We'll iterate through your existing $persons and their accounts, then build a new collection centered around En models, linking each to its associated Accounts and the parent Person:

// Initialize a collection to map En IDs to their instances with relationships
$enCollection = collect();

foreach ($persons as $person) {
    foreach ($person->accounts as $account) {
        $en = $account->en;
        
        // If this En isn't in our collection yet, set it up with an empty accounts collection
        if (!$enCollection->has($en->getKey())) {
            // Add an empty "accounts" collection to the En instance
            $en->accounts = collect();
            $enCollection->put($en->getKey(), $en);
        }
        
        // Attach the parent Person to the Account
        $account->person = $person;
        
        // Push the Account to the corresponding En's accounts collection
        $enCollection->get($en->getKey())->accounts->push($account);
    }
}

// Extract the final En collection (values() removes the ID keys)
$ens = $enCollection->values();

Now you can access properties exactly as you wanted:

// Example access
echo $ens[0]->e1; // Direct En property
echo $ens[0]->accounts[0]->a1; // Account property
echo $ens[0]->accounts[0]->person->p1; // Person property through Account

Step 3: (Optional) Define Permanent Reverse Relationships #

For a more "native" Eloquent experience, define the reverse relationships in your models so you can query this structure directly from the database without manually restructuring collections:

In your En model: #

public function accounts()
{
    return $this->hasMany(Account::class);
}

// Optional: If you need direct access from En to Person (bypassing Account)
public function persons()
{
    return $this->hasManyThrough(Person::class, Account::class);
}

In your Account model: #

public function person()
{
    return $this->belongsTo(Person::class);
}

With these relationships defined, you can fetch the structured collection directly like this:

$ens = En::with('accounts.person')->get();

内容的提问来源于stack exchange，提问作者Mostafa Abedi