N-Ary Relationship With Cactiverecord

Yii 1.1 General Discussion
1

Hello,

is it possible to model ternary relationship with CActiveRecord?

I mean three tables and a relationship table with foreign keys into them.

Regards,

Jiri

2

Hi jiri, welcome to the forum.

Would you please elaborate the issue and your needs with a sample?

For example,




Table_A ... id, name, field_a1, field_a2

Table_B ... id, name, field_b1, field_b2

Table_C ... id, name, field_c1, field_c2

Table_R ... a_id, b_id, c_id

...

The above is what comes to my mind with your brief explanation, but I couldn’t imagine any further about the relations between A, B and C.

3

Hi,

yes this is the schema I had in mind.

Now, say, the tables are department, section and budget. Meaning the department has separate budget for several sections.

Can I the get section/budget pars for the department via some CActiveRecord magic?

Of course I know how to do it in plain sql.

Thanks,

Jiri

4

I see.

As you see in the guide, Yii supports 4 kinds of relationship between the active record models.

http://www.yiiframework.com/doc/guide/1.1/en/database.arr#declaring-relationship

BELONGS_TO, HAS_MANY, HAS_ONE and MANY_MANY

The things will be much easier bearing that in mind.

I would design the tables like the following:




tbl_department

  id ... AI PK

  name

  ...

tbl_section

  id ... AI PK

  department_id ... FK to tbl_dpartment.id

  name

  ...

tbl_budget

  id ... AI PK

  section_id ... FK to tbl_section.id

  amount

  ...

I would not create the link table.

A Department HAS_MANY Sections, and a Section HAS_ONE Budget.

Now you will be able to access the sections and their budget like the following:




$dept = Department::model()->findByPk($id);

echo "Department = " . $dpt->name . "\n";

foreach($dept->sections as $section) {

    echo "Section = " . $section->name . "\n";

    echo "Budget = " . $section->budget->amount . "\n";

}