master

laravel/framework

Last updated at: 29/12/2023 09:22

HasRelationships.php

TLDR

HasRelationships.php is a trait file that provides various relationship methods for models in the Illuminate\Database\Eloquent namespace. It defines methods for defining and instantiating different types of relationships such as hasOne, hasMany, belongsTo, belongsToMany, morphOne, morphTo, morphMany, and morphToMany.

Methods

relationResolver

This method retrieves the dynamic relation resolver for a given class and key.

resolveRelationUsing

This method defines a dynamic relation resolver for a given name and callback.

hasOne

This method defines a one-to-one relationship.

hasOneThrough

This method defines a has-one-through relationship.

morphOne

This method defines a polymorphic one-to-one relationship.

belongsTo

This method defines an inverse one-to-one or many relationship.

morphTo

This method defines a polymorphic, inverse one-to-one or many relationship.

through

This method creates a pending has-many-through or has-one-through relationship.

hasMany

This method defines a one-to-many relationship.

hasManyThrough

This method defines a has-many-through relationship.

morphMany

This method defines a polymorphic one-to-many relationship.

belongsToMany

This method defines a many-to-many relationship.

morphToMany

This method defines a polymorphic many-to-many relationship.

morphedByMany

This method defines a polymorphic, inverse many-to-many relationship.

touches

This method determines if the model touches a given relation.

touchOwners

This method touches the owning relations of the model.

getMorphs

This method gets the polymorphic relationship columns.

getMorphClass

This method gets the class name for polymorphic relations.

joiningTable

This method gets the joining table name for a many-to-many relation.

joiningTableSegment

This method gets this model's half of the intermediate table name for belongsToMany relationships.

getRelations

This method gets all the loaded relations for the instance.

getRelation

This method gets a specified relationship.

relationLoaded

This method determines if the given relation is loaded.

setRelation

This method sets the given relationship on the model.

unsetRelation

This method unsets a loaded relationship.

setRelations

This method sets the entire relations array on the model.

withoutRelations

This method duplicates the instance and unsets all the loaded relations.

unsetRelations

This method unsets all the loaded relations for the instance.

getTouchedRelations

This method gets the relationships that are touched on save.

setTouchedRelations

This method sets the relationships that are touched on save.

Classes

None

<?php

namespace Illuminate\Database\Eloquent\Concerns;

use Closure;
use Illuminate\Database\ClassMorphViolationException;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Collection;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\PendingHasThroughRelationship;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\Relations\HasManyThrough;
use Illuminate\Database\Eloquent\Relations\HasOne;
use Illuminate\Database\Eloquent\Relations\HasOneThrough;
use Illuminate\Database\Eloquent\Relations\MorphMany;
use Illuminate\Database\Eloquent\Relations\MorphOne;
use Illuminate\Database\Eloquent\Relations\MorphTo;
use Illuminate\Database\Eloquent\Relations\MorphToMany;
use Illuminate\Database\Eloquent\Relations\Pivot;
use Illuminate\Database\Eloquent\Relations\Relation;
use Illuminate\Support\Arr;
use Illuminate\Support\Str;

trait HasRelationships
{
    /**
     * The loaded relationships for the model.
     *
     * @var array
     */
    protected $relations = [];

    /**
     * The relationships that should be touched on save.
     *
     * @var array
     */
    protected $touches = [];

    /**
     * The many to many relationship methods.
     *
     * @var string[]
     */
    public static $manyMethods = [
        'belongsToMany', 'morphToMany', 'morphedByMany',
    ];

    /**
     * The relation resolver callbacks.
     *
     * @var array
     */
    protected static $relationResolvers = [];

    /**
     * Get the dynamic relation resolver if defined or inherited, or return null.
     *
     * @param  string  $class
     * @param  string  $key
     * @return mixed
     */
    public function relationResolver($class, $key)
    {
        if ($resolver = static::$relationResolvers[$class][$key] ?? null) {
            return $resolver;
        }

        if ($parent = get_parent_class($class)) {
            return $this->relationResolver($parent, $key);
        }

        return null;
    }

    /**
     * Define a dynamic relation resolver.
     *
     * @param  string  $name
     * @param  \Closure  $callback
     * @return void
     */
    public static function resolveRelationUsing($name, Closure $callback)
    {
        static::$relationResolvers = array_replace_recursive(
            static::$relationResolvers,
            [static::class => [$name => $callback]]
        );
    }

    /**
     * Define a one-to-one relationship.
     *
     * @param  string  $related
     * @param  string|null  $foreignKey
     * @param  string|null  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\HasOne
     */
    public function hasOne($related, $foreignKey = null, $localKey = null)
    {
        $instance = $this->newRelatedInstance($related);

        $foreignKey = $foreignKey ?: $this->getForeignKey();

        $localKey = $localKey ?: $this->getKeyName();

        return $this->newHasOne($instance->newQuery(), $this, $instance->getTable().'.'.$foreignKey, $localKey);
    }

    /**
     * Instantiate a new HasOne relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $parent
     * @param  string  $foreignKey
     * @param  string  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\HasOne
     */
    protected function newHasOne(Builder $query, Model $parent, $foreignKey, $localKey)
    {
        return new HasOne($query, $parent, $foreignKey, $localKey);
    }

    /**
     * Define a has-one-through relationship.
     *
     * @param  string  $related
     * @param  string  $through
     * @param  string|null  $firstKey
     * @param  string|null  $secondKey
     * @param  string|null  $localKey
     * @param  string|null  $secondLocalKey
     * @return \Illuminate\Database\Eloquent\Relations\HasOneThrough
     */
    public function hasOneThrough($related, $through, $firstKey = null, $secondKey = null, $localKey = null, $secondLocalKey = null)
    {
        $through = $this->newRelatedThroughInstance($through);

        $firstKey = $firstKey ?: $this->getForeignKey();

        $secondKey = $secondKey ?: $through->getForeignKey();

        return $this->newHasOneThrough(
            $this->newRelatedInstance($related)->newQuery(), $this, $through,
            $firstKey, $secondKey, $localKey ?: $this->getKeyName(),
            $secondLocalKey ?: $through->getKeyName()
        );
    }

    /**
     * Instantiate a new HasOneThrough relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $farParent
     * @param  \Illuminate\Database\Eloquent\Model  $throughParent
     * @param  string  $firstKey
     * @param  string  $secondKey
     * @param  string  $localKey
     * @param  string  $secondLocalKey
     * @return \Illuminate\Database\Eloquent\Relations\HasOneThrough
     */
    protected function newHasOneThrough(Builder $query, Model $farParent, Model $throughParent, $firstKey, $secondKey, $localKey, $secondLocalKey)
    {
        return new HasOneThrough($query, $farParent, $throughParent, $firstKey, $secondKey, $localKey, $secondLocalKey);
    }

    /**
     * Define a polymorphic one-to-one relationship.
     *
     * @param  string  $related
     * @param  string  $name
     * @param  string|null  $type
     * @param  string|null  $id
     * @param  string|null  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphOne
     */
    public function morphOne($related, $name, $type = null, $id = null, $localKey = null)
    {
        $instance = $this->newRelatedInstance($related);

        [$type, $id] = $this->getMorphs($name, $type, $id);

        $table = $instance->getTable();

        $localKey = $localKey ?: $this->getKeyName();

        return $this->newMorphOne($instance->newQuery(), $this, $table.'.'.$type, $table.'.'.$id, $localKey);
    }

    /**
     * Instantiate a new MorphOne relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $parent
     * @param  string  $type
     * @param  string  $id
     * @param  string  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphOne
     */
    protected function newMorphOne(Builder $query, Model $parent, $type, $id, $localKey)
    {
        return new MorphOne($query, $parent, $type, $id, $localKey);
    }

    /**
     * Define an inverse one-to-one or many relationship.
     *
     * @param  string  $related
     * @param  string|null  $foreignKey
     * @param  string|null  $ownerKey
     * @param  string|null  $relation
     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function belongsTo($related, $foreignKey = null, $ownerKey = null, $relation = null)
    {
        // If no relation name was given, we will use this debug backtrace to extract
        // the calling method's name and use that as the relationship name as most
        // of the time this will be what we desire to use for the relationships.
        if (is_null($relation)) {
            $relation = $this->guessBelongsToRelation();
        }

        $instance = $this->newRelatedInstance($related);

        // If no foreign key was supplied, we can use a backtrace to guess the proper
        // foreign key name by using the name of the relationship function, which
        // when combined with an "_id" should conventionally match the columns.
        if (is_null($foreignKey)) {
            $foreignKey = Str::snake($relation).'_'.$instance->getKeyName();
        }

        // Once we have the foreign key names we'll just create a new Eloquent query
        // for the related models and return the relationship instance which will
        // actually be responsible for retrieving and hydrating every relation.
        $ownerKey = $ownerKey ?: $instance->getKeyName();

        return $this->newBelongsTo(
            $instance->newQuery(), $this, $foreignKey, $ownerKey, $relation
        );
    }

    /**
     * Instantiate a new BelongsTo relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $child
     * @param  string  $foreignKey
     * @param  string  $ownerKey
     * @param  string  $relation
     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    protected function newBelongsTo(Builder $query, Model $child, $foreignKey, $ownerKey, $relation)
    {
        return new BelongsTo($query, $child, $foreignKey, $ownerKey, $relation);
    }

    /**
     * Define a polymorphic, inverse one-to-one or many relationship.
     *
     * @param  string|null  $name
     * @param  string|null  $type
     * @param  string|null  $id
     * @param  string|null  $ownerKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphTo
     */
    public function morphTo($name = null, $type = null, $id = null, $ownerKey = null)
    {
        // If no name is provided, we will use the backtrace to get the function name
        // since that is most likely the name of the polymorphic interface. We can
        // use that to get both the class and foreign key that will be utilized.
        $name = $name ?: $this->guessBelongsToRelation();

        [$type, $id] = $this->getMorphs(
            Str::snake($name), $type, $id
        );

        // If the type value is null it is probably safe to assume we're eager loading
        // the relationship. In this case we'll just pass in a dummy query where we
        // need to remove any eager loads that may already be defined on a model.
        return is_null($class = $this->getAttributeFromArray($type)) || $class === ''
                    ? $this->morphEagerTo($name, $type, $id, $ownerKey)
                    : $this->morphInstanceTo($class, $name, $type, $id, $ownerKey);
    }

    /**
     * Define a polymorphic, inverse one-to-one or many relationship.
     *
     * @param  string  $name
     * @param  string  $type
     * @param  string  $id
     * @param  string  $ownerKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphTo
     */
    protected function morphEagerTo($name, $type, $id, $ownerKey)
    {
        return $this->newMorphTo(
            $this->newQuery()->setEagerLoads([]), $this, $id, $ownerKey, $type, $name
        );
    }

    /**
     * Define a polymorphic, inverse one-to-one or many relationship.
     *
     * @param  string  $target
     * @param  string  $name
     * @param  string  $type
     * @param  string  $id
     * @param  string  $ownerKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphTo
     */
    protected function morphInstanceTo($target, $name, $type, $id, $ownerKey)
    {
        $instance = $this->newRelatedInstance(
            static::getActualClassNameForMorph($target)
        );

        return $this->newMorphTo(
            $instance->newQuery(), $this, $id, $ownerKey ?? $instance->getKeyName(), $type, $name
        );
    }

    /**
     * Instantiate a new MorphTo relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $parent
     * @param  string  $foreignKey
     * @param  string  $ownerKey
     * @param  string  $type
     * @param  string  $relation
     * @return \Illuminate\Database\Eloquent\Relations\MorphTo
     */
    protected function newMorphTo(Builder $query, Model $parent, $foreignKey, $ownerKey, $type, $relation)
    {
        return new MorphTo($query, $parent, $foreignKey, $ownerKey, $type, $relation);
    }

    /**
     * Retrieve the actual class name for a given morph class.
     *
     * @param  string  $class
     * @return string
     */
    public static function getActualClassNameForMorph($class)
    {
        return Arr::get(Relation::morphMap() ?: [], $class, $class);
    }

    /**
     * Guess the "belongs to" relationship name.
     *
     * @return string
     */
    protected function guessBelongsToRelation()
    {
        [$one, $two, $caller] = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 3);

        return $caller['function'];
    }

    /**
     * Create a pending has-many-through or has-one-through relationship.
     *
     * @param  string|\Illuminate\Database\Eloquent\Relations\HasMany|\Illuminate\Database\Eloquent\Relations\HasOne  $relationship
     * @return \Illuminate\Database\Eloquent\PendingHasThroughRelationship
     */
    public function through($relationship)
    {
        if (is_string($relationship)) {
            $relationship = $this->{$relationship}();
        }

        return new PendingHasThroughRelationship($this, $relationship);
    }

    /**
     * Define a one-to-many relationship.
     *
     * @param  string  $related
     * @param  string|null  $foreignKey
     * @param  string|null  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\HasMany
     */
    public function hasMany($related, $foreignKey = null, $localKey = null)
    {
        $instance = $this->newRelatedInstance($related);

        $foreignKey = $foreignKey ?: $this->getForeignKey();

        $localKey = $localKey ?: $this->getKeyName();

        return $this->newHasMany(
            $instance->newQuery(), $this, $instance->getTable().'.'.$foreignKey, $localKey
        );
    }

    /**
     * Instantiate a new HasMany relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $parent
     * @param  string  $foreignKey
     * @param  string  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\HasMany
     */
    protected function newHasMany(Builder $query, Model $parent, $foreignKey, $localKey)
    {
        return new HasMany($query, $parent, $foreignKey, $localKey);
    }

    /**
     * Define a has-many-through relationship.
     *
     * @param  string  $related
     * @param  string  $through
     * @param  string|null  $firstKey
     * @param  string|null  $secondKey
     * @param  string|null  $localKey
     * @param  string|null  $secondLocalKey
     * @return \Illuminate\Database\Eloquent\Relations\HasManyThrough
     */
    public function hasManyThrough($related, $through, $firstKey = null, $secondKey = null, $localKey = null, $secondLocalKey = null)
    {
        $through = $this->newRelatedThroughInstance($through);

        $firstKey = $firstKey ?: $this->getForeignKey();

        $secondKey = $secondKey ?: $through->getForeignKey();

        return $this->newHasManyThrough(
            $this->newRelatedInstance($related)->newQuery(),
            $this,
            $through,
            $firstKey,
            $secondKey,
            $localKey ?: $this->getKeyName(),
            $secondLocalKey ?: $through->getKeyName()
        );
    }

    /**
     * Instantiate a new HasManyThrough relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $farParent
     * @param  \Illuminate\Database\Eloquent\Model  $throughParent
     * @param  string  $firstKey
     * @param  string  $secondKey
     * @param  string  $localKey
     * @param  string  $secondLocalKey
     * @return \Illuminate\Database\Eloquent\Relations\HasManyThrough
     */
    protected function newHasManyThrough(Builder $query, Model $farParent, Model $throughParent, $firstKey, $secondKey, $localKey, $secondLocalKey)
    {
        return new HasManyThrough($query, $farParent, $throughParent, $firstKey, $secondKey, $localKey, $secondLocalKey);
    }

    /**
     * Define a polymorphic one-to-many relationship.
     *
     * @param  string  $related
     * @param  string  $name
     * @param  string|null  $type
     * @param  string|null  $id
     * @param  string|null  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphMany
     */
    public function morphMany($related, $name, $type = null, $id = null, $localKey = null)
    {
        $instance = $this->newRelatedInstance($related);

        // Here we will gather up the morph type and ID for the relationship so that we
        // can properly query the intermediate table of a relation. Finally, we will
        // get the table and create the relationship instances for the developers.
        [$type, $id] = $this->getMorphs($name, $type, $id);

        $table = $instance->getTable();

        $localKey = $localKey ?: $this->getKeyName();

        return $this->newMorphMany($instance->newQuery(), $this, $table.'.'.$type, $table.'.'.$id, $localKey);
    }

    /**
     * Instantiate a new MorphMany relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $parent
     * @param  string  $type
     * @param  string  $id
     * @param  string  $localKey
     * @return \Illuminate\Database\Eloquent\Relations\MorphMany
     */
    protected function newMorphMany(Builder $query, Model $parent, $type, $id, $localKey)
    {
        return new MorphMany($query, $parent, $type, $id, $localKey);
    }

    /**
     * Define a many-to-many relationship.
     *
     * @param  string  $related
     * @param  string|class-string<\Illuminate\Database\Eloquent\Model>|null  $table
     * @param  string|null  $foreignPivotKey
     * @param  string|null  $relatedPivotKey
     * @param  string|null  $parentKey
     * @param  string|null  $relatedKey
     * @param  string|null  $relation
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function belongsToMany($related, $table = null, $foreignPivotKey = null, $relatedPivotKey = null,
                                  $parentKey = null, $relatedKey = null, $relation = null)
    {
        // If no relationship name was passed, we will pull backtraces to get the
        // name of the calling function. We will use that function name as the
        // title of this relation since that is a great convention to apply.
        if (is_null($relation)) {
            $relation = $this->guessBelongsToManyRelation();
        }

        // First, we'll need to determine the foreign key and "other key" for the
        // relationship. Once we have determined the keys we'll make the query
        // instances as well as the relationship instances we need for this.
        $instance = $this->newRelatedInstance($related);

        $foreignPivotKey = $foreignPivotKey ?: $this->getForeignKey();

        $relatedPivotKey = $relatedPivotKey ?: $instance->getForeignKey();

        // If no table name was provided, we can guess it by concatenating the two
        // models using underscores in alphabetical order. The two model names
        // are transformed to snake case from their default CamelCase also.
        if (is_null($table)) {
            $table = $this->joiningTable($related, $instance);
        }

        return $this->newBelongsToMany(
            $instance->newQuery(), $this, $table, $foreignPivotKey,
            $relatedPivotKey, $parentKey ?: $this->getKeyName(),
            $relatedKey ?: $instance->getKeyName(), $relation
        );
    }

    /**
     * Instantiate a new BelongsToMany relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $parent
     * @param  string|class-string<\Illuminate\Database\Eloquent\Model>  $table
     * @param  string  $foreignPivotKey
     * @param  string  $relatedPivotKey
     * @param  string  $parentKey
     * @param  string  $relatedKey
     * @param  string|null  $relationName
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    protected function newBelongsToMany(Builder $query, Model $parent, $table, $foreignPivotKey, $relatedPivotKey,
                                        $parentKey, $relatedKey, $relationName = null)
    {
        return new BelongsToMany($query, $parent, $table, $foreignPivotKey, $relatedPivotKey, $parentKey, $relatedKey, $relationName);
    }

    /**
     * Define a polymorphic many-to-many relationship.
     *
     * @param  string  $related
     * @param  string  $name
     * @param  string|null  $table
     * @param  string|null  $foreignPivotKey
     * @param  string|null  $relatedPivotKey
     * @param  string|null  $parentKey
     * @param  string|null  $relatedKey
     * @param  string|null  $relation
     * @param  bool  $inverse
     * @return \Illuminate\Database\Eloquent\Relations\MorphToMany
     */
    public function morphToMany($related, $name, $table = null, $foreignPivotKey = null,
                                $relatedPivotKey = null, $parentKey = null,
                                $relatedKey = null, $relation = null, $inverse = false)
    {
        $relation = $relation ?: $this->guessBelongsToManyRelation();

        // First, we will need to determine the foreign key and "other key" for the
        // relationship. Once we have determined the keys we will make the query
        // instances, as well as the relationship instances we need for these.
        $instance = $this->newRelatedInstance($related);

        $foreignPivotKey = $foreignPivotKey ?: $name.'_id';

        $relatedPivotKey = $relatedPivotKey ?: $instance->getForeignKey();

        // Now we're ready to create a new query builder for the related model and
        // the relationship instances for this relation. This relation will set
        // appropriate query constraints then entirely manage the hydrations.
        if (! $table) {
            $words = preg_split('/(_)/u', $name, -1, PREG_SPLIT_DELIM_CAPTURE);

            $lastWord = array_pop($words);

            $table = implode('', $words).Str::plural($lastWord);
        }

        return $this->newMorphToMany(
            $instance->newQuery(), $this, $name, $table,
            $foreignPivotKey, $relatedPivotKey, $parentKey ?: $this->getKeyName(),
            $relatedKey ?: $instance->getKeyName(), $relation, $inverse
        );
    }

    /**
     * Instantiate a new MorphToMany relationship.
     *
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @param  \Illuminate\Database\Eloquent\Model  $parent
     * @param  string  $name
     * @param  string  $table
     * @param  string  $foreignPivotKey
     * @param  string  $relatedPivotKey
     * @param  string  $parentKey
     * @param  string  $relatedKey
     * @param  string|null  $relationName
     * @param  bool  $inverse
     * @return \Illuminate\Database\Eloquent\Relations\MorphToMany
     */
    protected function newMorphToMany(Builder $query, Model $parent, $name, $table, $foreignPivotKey,
                                      $relatedPivotKey, $parentKey, $relatedKey,
                                      $relationName = null, $inverse = false)
    {
        return new MorphToMany($query, $parent, $name, $table, $foreignPivotKey, $relatedPivotKey, $parentKey, $relatedKey,
            $relationName, $inverse);
    }

    /**
     * Define a polymorphic, inverse many-to-many relationship.
     *
     * @param  string  $related
     * @param  string  $name
     * @param  string|null  $table
     * @param  string|null  $foreignPivotKey
     * @param  string|null  $relatedPivotKey
     * @param  string|null  $parentKey
     * @param  string|null  $relatedKey
     * @param  string|null  $relation
     * @return \Illuminate\Database\Eloquent\Relations\MorphToMany
     */
    public function morphedByMany($related, $name, $table = null, $foreignPivotKey = null,
                                  $relatedPivotKey = null, $parentKey = null, $relatedKey = null, $relation = null)
    {
        $foreignPivotKey = $foreignPivotKey ?: $this->getForeignKey();

        // For the inverse of the polymorphic many-to-many relations, we will change
        // the way we determine the foreign and other keys, as it is the opposite
        // of the morph-to-many method since we're figuring out these inverses.
        $relatedPivotKey = $relatedPivotKey ?: $name.'_id';

        return $this->morphToMany(
            $related, $name, $table, $foreignPivotKey,
            $relatedPivotKey, $parentKey, $relatedKey, $relation, true
        );
    }

    /**
     * Get the relationship name of the belongsToMany relationship.
     *
     * @return string|null
     */
    protected function guessBelongsToManyRelation()
    {
        $caller = Arr::first(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS), function ($trace) {
            return ! in_array(
                $trace['function'],
                array_merge(static::$manyMethods, ['guessBelongsToManyRelation'])
            );
        });

        return ! is_null($caller) ? $caller['function'] : null;
    }

    /**
     * Get the joining table name for a many-to-many relation.
     *
     * @param  string  $related
     * @param  \Illuminate\Database\Eloquent\Model|null  $instance
     * @return string
     */
    public function joiningTable($related, $instance = null)
    {
        // The joining table name, by convention, is simply the snake cased models
        // sorted alphabetically and concatenated with an underscore, so we can
        // just sort the models and join them together to get the table name.
        $segments = [
            $instance ? $instance->joiningTableSegment()
                      : Str::snake(class_basename($related)),
            $this->joiningTableSegment(),
        ];

        // Now that we have the model names in an array we can just sort them and
        // use the implode function to join them together with an underscores,
        // which is typically used by convention within the database system.
        sort($segments);

        return strtolower(implode('_', $segments));
    }

    /**
     * Get this model's half of the intermediate table name for belongsToMany relationships.
     *
     * @return string
     */
    public function joiningTableSegment()
    {
        return Str::snake(class_basename($this));
    }

    /**
     * Determine if the model touches a given relation.
     *
     * @param  string  $relation
     * @return bool
     */
    public function touches($relation)
    {
        return in_array($relation, $this->getTouchedRelations());
    }

    /**
     * Touch the owning relations of the model.
     *
     * @return void
     */
    public function touchOwners()
    {
        foreach ($this->getTouchedRelations() as $relation) {
            $this->$relation()->touch();

            if ($this->$relation instanceof self) {
                $this->$relation->fireModelEvent('saved', false);

                $this->$relation->touchOwners();
            } elseif ($this->$relation instanceof Collection) {
                $this->$relation->each->touchOwners();
            }
        }
    }

    /**
     * Get the polymorphic relationship columns.
     *
     * @param  string  $name
     * @param  string  $type
     * @param  string  $id
     * @return array
     */
    protected function getMorphs($name, $type, $id)
    {
        return [$type ?: $name.'_type', $id ?: $name.'_id'];
    }

    /**
     * Get the class name for polymorphic relations.
     *
     * @return string
     */
    public function getMorphClass()
    {
        $morphMap = Relation::morphMap();

        if (! empty($morphMap) && in_array(static::class, $morphMap)) {
            return array_search(static::class, $morphMap, true);
        }

        if (static::class === Pivot::class) {
            return static::class;
        }

        if (Relation::requiresMorphMap()) {
            throw new ClassMorphViolationException($this);
        }

        return static::class;
    }

    /**
     * Create a new model instance for a related model.
     *
     * @param  string  $class
     * @return mixed
     */
    protected function newRelatedInstance($class)
    {
        return tap(new $class, function ($instance) {
            if (! $instance->getConnectionName()) {
                $instance->setConnection($this->connection);
            }
        });
    }

    /**
     * Create a new model instance for a related "through" model.
     *
     * @param  string  $class
     * @return mixed
     */
    protected function newRelatedThroughInstance($class)
    {
        return new $class;
    }

    /**
     * Get all the loaded relations for the instance.
     *
     * @return array
     */
    public function getRelations()
    {
        return $this->relations;
    }

    /**
     * Get a specified relationship.
     *
     * @param  string  $relation
     * @return mixed
     */
    public function getRelation($relation)
    {
        return $this->relations[$relation];
    }

    /**
     * Determine if the given relation is loaded.
     *
     * @param  string  $key
     * @return bool
     */
    public function relationLoaded($key)
    {
        return array_key_exists($key, $this->relations);
    }

    /**
     * Set the given relationship on the model.
     *
     * @param  string  $relation
     * @param  mixed  $value
     * @return $this
     */
    public function setRelation($relation, $value)
    {
        $this->relations[$relation] = $value;

        return $this;
    }

    /**
     * Unset a loaded relationship.
     *
     * @param  string  $relation
     * @return $this
     */
    public function unsetRelation($relation)
    {
        unset($this->relations[$relation]);

        return $this;
    }

    /**
     * Set the entire relations array on the model.
     *
     * @param  array  $relations
     * @return $this
     */
    public function setRelations(array $relations)
    {
        $this->relations = $relations;

        return $this;
    }

    /**
     * Duplicate the instance and unset all the loaded relations.
     *
     * @return $this
     */
    public function withoutRelations()
    {
        $model = clone $this;

        return $model->unsetRelations();
    }

    /**
     * Unset all the loaded relations for the instance.
     *
     * @return $this
     */
    public function unsetRelations()
    {
        $this->relations = [];

        return $this;
    }

    /**
     * Get the relationships that are touched on save.
     *
     * @return array
     */
    public function getTouchedRelations()
    {
        return $this->touches;
    }

    /**
     * Set the relationships that are touched on save.
     *
     * @param  array  $touches
     * @return $this
     */
    public function setTouchedRelations(array $touches)
    {
        $this->touches = $touches;

        return $this;
    }
}