datatable.directory/app/Models/Revision.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Riesjart\Relaquent\Model\Concerns\HasRelaquentRelationships;

/**
 * Table revision (a set of rows)
 */
class Revision extends Model
{
    use HasRelaquentRelationships;

    protected static function boot()
    {
        parent::boot();

        static::deleting(function(Revision $self) {
            // update refcounts
            $self->rows()->decrement('refs');
        });
    }

    /** Included rows */
    public function rows()
    {
        return $this->belongsToMany(Row::class, 'revision_row_pivot');
    }

    /** Proposal that lead to this revision */
    public function appliedProposal()
    {
        return $this->hasOneThrough(Proposal::class, 'revision_proposal_pivot');
    }

    /** Proposals that depend on this revision */
    public function dependentProposals()
    {
        return $this->hasMany(Proposal::class);
    }

    /** Revision this orignates from */
    public function parentRevision()
    {
        return $this->belongsTo(Revision::class, 'ancestor_id');
    }

    /** Tables referencing this revision */
    public function tables()
    {
        return $this->belongsToMany(Table::class, 'table_revision_pivot');
    }
}