最近想使用关联模型快速取数据，可是一直返回bool(false)，求热心人解答为什么TAT
以下是表和代码
1 数据表
CREATE TABLE `jj_teacher` (
`id` int(10) NOT NULL AUTO_INCREMENT ,
中间字段略过
PRIMARY KEY (`id`)
)

CREATE TABLE `jj_teacher_course` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`teacher_id` int(10) NOT NULL, //此处为关联teacher的id
中间字段略过
PRIMARY KEY (`id`),

)

2类
class TeacherModel extends RelationModel{

protected $tablePrefix = 'jj_';
protected $_link = array(
'TeacherCourse'=>array(
'mapping_type' =>HAS_MANY,
'class_name' =>'TeacherCourse',
'foreign_key' =>'teacher_id',
),
);
}
3结果
.......
["TeacherCourse"] => bool(false)