code: public function compile()
  	{
  		$sql = array($this->name);
  
  		$sql[] = $this->length !== null ?
  			$this->type."(".$this->length.")" :
  			$this->type;
  
  		if ( ! empty($this->options))
  		{
  			$sql = \array_merge($sql, $this->options);
  		}
  
  		if ($this->is_null !== null)
  		{
  			$sql[] = $this->is_null === true ? "NULL" : "NOT NULL";
  		}
  
  		if ($this->default !== null)
  		{
  			$sql[] = "DEFAULT {$this->default}";
  		}
  
  		if ($this->auto_increment === true)
  		{
  			$sql[] = "AUTO_INCREMENT";
  		}
  
  		return join(' ', $sql);
  	}
docs: {@inheritDoc}