使用symfony降低问题

Question

我是symfony的新手，我已经花了两天时间使用基于schema.yml的关系来解决使用symfony的问题
schema.yml是

FieldsCategory:
tableName: fld_category
columns:
    id: 
        name: id as FieldsId
        type: integer(10)
        primary: true
        autoincrement: true
    category_name: 
        name: category_name as CategoryName 
        type: string
        default: ''
        notnull: true 
relations:
    FieldsCategory:
        class: FieldsCategory
        foreignAlias: Fields
        local: id
        foreign: fields_category_id
Fields:      
 tableName: fld_fields  
   columns:
    id:
        name: id as FieldsId
        type: integer(10)
        primary: true
        autoincrement: true
    fields_name:
        name: fields_name as FieldsName
        type: string
        default: ''
        notnull: true
    fields_desc:
        name: fields_desc as FieldsDescription
        type: string
        default: ''
        notnull: true
    amount:
        name: amount as TotalAmount
        type: integer
        notnull: true
    fields_type_id:
        name: fields_type_id as FieldsTypeId
        type: integer
    fields_category_id:
        name: fields_category_id as FieldsCategoryId
        type: integer

我的表格是

$this->setWidgets(array(
  'FieldsId'   => new sfWidgetFormInputHidden(),
  'fields_type_id'       => new sfWidgetFormDoctrineChoice(array('model' => $this->getRelatedModelName('Fields'), 'add_empty' => false)),
  'FieldsName' => new sfWidgetFormTextarea(),
));

$this->setValidators(array(
  'FieldsId'   => new sfValidatorChoice(array('choices' => array($this->getObject()->get('FieldsId')), 'empty_value' => $this->getObject()->get('FieldsId'), 'required' => false)),
   'fields_type_id'       => new sfValidatorDoctrineChoice(array('model' => $this->getRelatedModelName('Fields'), 'required' => false)),
  'FieldsName' => new sfValidatorString(array('required' => false)),
));

它给了我这个错误

我已经尝试了所有可能的方法，但我无法解决这个问题/
并将提前帮助