在Yii2中使用关系联接多个表

Question

I am trying to list some data through Kartik GridView widget in yii2 by using relations. I have these tables

staffs

CREATE TABLE IF NOT EXISTS `staffs` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(250) CHARACTER SET utf8 DEFAULT NULL,
  `department_id` int(11) DEFAULT NULL,
  `designation_id` int(11) DEFAULT NULL,
  `username` varchar(50) CHARACTER SET utf8 DEFAULT NULL,
  `emailid` varchar(250) CHARACTER SET utf8 DEFAULT NULL,
  `staffrights` tinyint(2) DEFAULT '0',
  `staffstatus` tinyint(2) DEFAULT '1',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1;
designations

CREATE TABLE IF NOT EXISTS `designations` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `designname` varchar(150) NOT NULL,
  `designation_group_id` varchar(250) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1;



designation_group 


CREATE TABLE IF NOT EXISTS `designation_group` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `group_name` text NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1;

designations table is related to designation_group by designations.designation_group_id . designations table will have one or more values seperated by comma, of designation_group.id .

designations table is related to staffs table by staffs.designation_id =designations.id . In Staffs Model I have added relations like this

public function getDesignations() {
        return $this->hasOne( Designations::className(), ['id' => 'designation_id']);
    }

and is working perfect. But the relation for designation_group I tried like this:

public function getDesgroupstaffs(){
        return $this->hasOne(Designations::className() , ['id' => 'id'])
                    ->from(Designationgroup::tableName() ) ;
}

But it doesnt give the expected result. How the designation_group table can be joined so that all the designation group associated with the staff can also be displayed ? I want to show like, the first column of grid view will be designations, while filter of the same column should be DesignationGroup.group_name. SO if any group_name is selected , it will show data of staffs associated with that group name

Answer 1

Well, from what I was able to extract from your question, you want to be able to get the group name for each of the staffs. The code below will help you accomplish that task.

Inside the staff model, create a relationship as stated below or you can use an existing one which I am sure Yii would have automatically generated it for you

STAFF model

public function getDesignation()
{
   return $this->hasOne(Designation::className(),['designation_id'=>'id]);
}

Inside the designation model,create another relation that links the degination model with the designationGroup model, which would have been automatically created as well

Designation MOdel

public function getDesignationGroup()
{
   return $this->hasOne(DesignationGroup::className(),['id'=>'designation_group_id]);
}

Finally, on your gridview, you can use the code below to get the group name

$model->destination->designationGroup->group_name

I hope this solves your problem. Though i have used it couple of times.

Answer 2

If I understand you, it's looks like my problem a few days ago. check this out

I have three tables (contact, contact_groups and contact_contact_groups) which has many-to-many relation. It means one contact has many groups, and one group has many contacts. So I create one table to make relations One-to-Many.

but the result will like this :

contact | contact groups
-------------------------
contact #1 | business1, business2, family
contact #2 | family
contact #3 | student, partner

Answer 3

staff model

use ->with(['designationgroup'])

public function getDesignation()
{
   return $this->hasOne(Designation::className(),['designation_id'=>'id])->with(['designationgroup']);
}

designation model

public function getDesignationgroup()
{
   return $this->hasOne(DesignationGroup::className(),['id'=>'designation_group_id]);
}

On GridView , render the value as

$model->destination->designationgroup->group_name

Hope it helps.

Answer 4

I will suggest you to remove the column designation_group_id from designation table, because it contains multiples comma separated values. Create one more table named designation_group_assigned, which will have the following columns: Id , designation_id , designation_group_id

In this table, we can insert multiple rows if one designation belongs to multiple groups.

And then you can use the yii relationships for one to many records.