title: Unable to insert into PostgreSQL using laravel eloquent ORM
body: <p>I did my research a lot before posting this.</p>
  
  <p>I am getting the following error when trying to insert a record into PostgreSQL using Laravel eloquent ORM.</p>
  
  <p>This is the error: </p>
  
  <pre><code>Illuminate \ Database \ QueryException
  
  SQLSTATE[42703]: Undefined column: 
  7 ERROR: column "id" does not exist LINE 1: ...ed_at", "created_at") 
  values ($1, $2, $3, $4) 
  returning "id" ^ (SQL: insert into "fb_post_like_counts" ("post_id", "count", "updated_at", "created_at") values (293843523498_10152007721598499, 0, 2014-03-12 16:56:24, 2014-03-12 16:56:24) returning "id")
  </code></pre>
  
  <p>This is the database table create schema:</p>
  
  <pre><code>Schema::create('fb_post_shares_counts', function($table)
  {
      //
      $table-&gt;string('post_id');
      $table-&gt;string('count')-&gt;default(0);
  
      //  created_at updated_at deleted_at
      $table-&gt;timestamps();
      $table-&gt;softDeletes();
  
      // set composite keys   
      $table-&gt;primary(array('post_id', 'updated_at'));
  });
  </code></pre>
  
  <p>and this is the code i am trying to execute:</p>
  
  <pre><code>// SAVE POST SHARES
  $post_share_count   =   new FbPostShareCount;
  $post_share_count-&gt;post_id   =  $response['id'];
  $post_share_count-&gt;count    =   $fql_post['share_count'];       
  $post_share_count-&gt;save();
  </code></pre>
  
  <p>and I created a model class FbPostShareCount extends Eloquent.</p>
  
  <p>I know that laravel does not support complex keys but this problem did not occur when I was using MySQL </p>