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ISA hierarchy of tables inside a database and how to implement a single form

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ISA hierarchy of tables inside a database and how to implement a single form

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ISA, hierarchy, modelling

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[...]
Remember the parent class (created from gii) has already access to its children from the public function relations. So exploit this to get the child object.

Note: that this solution works only if row of A has ONLY ONE child, either B or C

The goal is to create a common form to fill the database tables a and b or c
So you need an attribute to differentiate the category. Is model A a parent of B or a parent of C? Once more you use custom properties. I used getCateg and setCateg methods. In my case if model A is a newRecord then the category is **null** but you may want to use a different solutionapproach

//...
[...]
-I create with the help of CHtml a drop down list so user can select B or C
This drop down list has values (0, 1) which correspond to class B or C
Therefore I have added to class A an array which remembers this correspondace from value => class
 
The textfield of the dropdown list is taken from an explanation function inside class B and class C
 
 
So ok the user has chosen the class. Now I would like to have a textbox to fill the attrB and attrC in a COMMON way.
 
I use the "activeForm" widget so I would like to keep all the functionality
 
 
Of course if I use a textbox for the model B I would have to add a SECOND textbox for the model C
 
Above solution is not at all intuitive for the user. We would not like to have two textboxes but a SINGLE textbox.
 
 
I added an attribute named let's say "attr" inside class A to play extra bonus is that this "categ" custom property is an attribute that can be used from the form widget and be validated
 
 
 
```php 
$attribute = "pvCat";
 
print $form->labelEx($model, $attribute);
 
print $form->dropDownList( $model, $attribute, $model::getCatDescs() );
 
print $form->error($model, $attribute);
 
```
 
 
As you see you have a seamless portion of code as the rest of the attributes which are real columns in table "a"
 
 
So the drole for both attrB and attrC
 
I also edited the "rules" method ofpdown list feeds the "categ" attribute
 
 
This way the used has chosen the class A. Now I could create a textbox based on model A.
 
When the user submits the form the controller distinguishes from the dropdown list whether we deal with B and C.
 
ISo you can now add a $protocol variable in your class A.
 
This protocol is only temporary and plays the same role for both class B and C.
 
This way you created a protected attribute to remember the choice of B or C
 
In that effect I created a new public method for class A where I could set this protected attribute and not only:
 
I use the relations to instantiate a new model B or C (for example $modelA->modelB = new modelB;)
 
I set the primary key of the model B (or C) according to the primary key of model A
 
and return the model B (or C) for further processing by the controllertextbox to fill protocol for either class B or class C in a seamless way.
 
 
 
```php 
$attribute = "protocol";
 
print $form->labelEx($model, $attribute);
 
print $form->textField($model, $attribute);
 
print $form->error($model, $attribute);
 
```
 
 
I also edited the "rules" method of class A. For instance the "categ" has the 'in' validator with a specific range SoBut currently I use the controller to call explicitly $modelB->save() or $modelC->save(). There wais an idea to override save() function in class A to automagically save the child model (since in object oriented terms the class/model A is an abstract class) Please let me know if that works better for you.
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Version: 1.1
Category: How-tos
Tags: hierarchy, ISA, modelling
Written by: pligor
Last updated by: pligor
Created on: Jun 27, 2011
Last updated: 13 years ago
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