Can Eloquent models retrieve metadata on their rows?

问题

Is it possible for an Eloquent-based model in Laravel to introspect/reflect on the underlying table and retrieve information (type, size, unsigned, default values, etc) about the columns?

Or is this intentionally left out?

I feel like it would be useful to be able to determine the column type (to do things like intelligently assign some validations, or help infer a form input type and/or populate a default).

回答1:

I don't think you can do this "out of the box" in Laravel, though it would be relatively easy to implement. Something along these lines, maybe?

<?php

class Model extends Eloquent {

    public function describe()
    {
        $table = $this->getTable();
        $pdo = \DB::connection()->getPdo();
        return $pdo->query("describe $table")->fetchAll();
    }
}

$model = new Model;
$columns = $model->describe();

// $columns:
array (
  0 => 
  array (
    'Field' => 'id',
    0 => 'id',
    'Type' => 'int(10) unsigned',
    1 => 'int(10) unsigned',
    'Null' => 'NO',
    2 => 'NO',
    'Key' => 'PRI',
    3 => 'PRI',
    'Default' => NULL,
    4 => NULL,
    'Extra' => 'auto_increment',
    5 => 'auto_increment',
  ),
  1 => 
  array (
    'Field' => 'created_at',
    0 => 'created_at',
    'Type' => 'timestamp',
    1 => 'timestamp',
    'Null' => 'NO',
    2 => 'NO',
    'Key' => '',
    3 => '',
    'Default' => '0000-00-00 00:00:00',
    4 => '0000-00-00 00:00:00',
    'Extra' => '',
    5 => '',
  ),
  ...

来源：https://stackoverflow.com/questions/24700739/can-eloquent-models-retrieve-metadata-on-their-rows