Question

Hope you are doing good.

I am new in extjs4 and working on sample example of association.

I have 2 different class User and Diploma
In relation, I have defined.

User hasMany Diplomas, and Diplomas belongsTo User

My models are as belows

User.js

Ext.define('MyApp.model.User', {
    extend : 'Ext.data.Model',
    idProperty : 'userId',
    fields : [{
        name : 'userId',
        type : 'integer'
    }, {
        name : 'userName',
        type : 'string',

    }],

    hasMany : {
        model : 'MyApp.model.Diploma',
        name : 'diplomas',
    },

});

Diploma.js

Ext.define('MyApp.model.Diploma', {
    extend : 'Ext.data.Model',
    idProperty : 'diplomaId',
    fields : [{
        name : 'diplomaId',
        type : 'integer'
    }, {
        name : 'diplomaName',
        type : 'string',
    }, {
        name : 'userId',
        type : 'integer'
    }],

    associations : [{
        model : 'MyApp.model.User',
        name : 'user',
        type : 'belongsTo'
    }]

});

=====================
My Stores are as below.========================

Diploma.js

Ext.define('MyApp.store.Diploma', {
    extend : 'Ext.data.Store',
    model : 'MyApp.model.Diploma',
    autoLoad : true,

    listeners : {
        'load' : {
            fn : function(store, records, success, operation) {
                console.log('Diplomas are loaded');
            }
        }
    }

});

User.js

  Ext.define('MyApp.store.User', {
        extend : 'Ext.data.Store',
        model : 'MyApp.model.User',
        requires:['Ext.data.proxy.LocalStorage'],
        autoLoad : true,

        listeners : {
            'load' : {
                fn : function(store, records, success, operation) {
                    console.log('User is loaded');
                }
            }
        },

        data : [{
            userId : 1,
            userName : 'Rishabh Shah',
            diplomas:{
                userId : 1,
                diplomaId:1,
                diplomaName:'IT'
            }
        }, {
            userId : 2,
            userName : 'Rakesh Shah',
            diplomas:{
                userId : 2,
                diplomaId:2,
                diplomaName:'CE'
            }
        }, {
            userId : 3,
            userName : 'Rashmin Shah'
        }],

        proxy:{
            type:'memory',
            reader:{
                root:'data'
            }
        }
    });

I can get diploma from user like that and can get result

Ext.getStore("User").getAt(0).diplomasStore.getAt(0)

but, when I try to do like

Ext.getStrore("Diploma") or Ext.getStrore("Diploma").getAt(0)

I don’t get anything. items contains nothing…
How can I get user from diploma.

and One more thing….if I don’t write proxy in my Diploma model..
it gives me an error like this..

Ext.data.proxy.Server.buildUrl(): You are using a ServerProxy but have not supplied it with a url.

Please guide me.

Thanks.

---

Thanks for your reply..@john..I can get diplomas from User..
I wanted to get user from diplomas…I tried it myself..and found solution…

I will have following json.

[
    {
        "depId": 1,
        "depName": "CE",
        "employees": [
            {
                "empId": 1,
                "firstName": "Rishabh",
                "lastName": "Shah"
            }, {
                "empId": 2,
                "firstName": "Smit",
                "lastName": "Patel"
            }
        ]
    }, {
        "depId": 2,
        "depName": "IT",
        "employees": [
            {
                "empId": 1,
                "firstName": "Parag",
                "lastName": "Raval"
            }, {
                "empId": 2,
                "firstName": "Rakesh",
                "lastName": "Prajapati"
            }
        ]
    }, {
        "depId": 3,
        "depName": "EE",
        "employees": [
            {
                "empId": 1,
                "firstName": "Parag EE",
                "lastName": "Raval EE"
            }, {
                "empId": 2,
                "firstName": "Rakesh EE",
                "lastName": "Prajapati EE"
            }
        ]
    }, {
        "depId": 4,
        "depName": "EC",
        "employees": [
            {
                "empId": 1,
                "firstName": "Parag EC",
                "lastName": "Raval EC"
            }, {
                "empId": 2,
                "firstName": "Rakesh EC",
                "lastName": "Prajapati EC"
            }
        ]
    }, {
        "depId": 5,
        "depName": "Chemial E",
        "employees": [
            {
                "empId": 1,
                "firstName": "Parag",
                "lastName": "Raval"
            }, {
                "empId": 2,
                "firstName": "Rakesh",
                "lastName": "Prajapati"
            }
        ]
    }, {
        "depId": 6,
        "depName": "ME",
        "employees": [
            {
                "empId": 1,
                "firstName": "Parag",
                "lastName": "Raval"
            }, {
                "empId": 2,
                "firstName": "Rakesh",
                "lastName": "Prajapati"
            }
        ]
    }, {
        "depId": 7,
        "depName": "Civil Engineer",
        "employees": [
            {
                "empId": 1,
                "firstName": "Parag",
                "lastName": "Raval"
            }, {
                "empId": 2,
                "firstName": "Rakesh",
                "lastName": "Prajapati"
            }
        ]
    }
]

and I will use model.getAssociatedData().user as per my requirement

where model is my record of child class and user is my parent class..

and I was using proxy in my Diploma Model which was not requierd….so, was getting

Ext.data.proxy.Server.buildUrl(): You are using a ServerProxy but have not supplied it with a url.

above mentioned error.

Thanks All ! 🙂

Answer 1

What exactly isn’t working? Have you been able to use the magic methods e.g., User.diplomas()? As @VDP stated, the store created for the Association is a normal Ext.data.Store scoped to the set of data for the parent model (in this case, User). That is to say, if you have a User model with the id of 1, calling the method User.diplomas() will return a Ext.data.Store filtered to contain only Diploma‘s with a user_id of 1.

This is very important to understand! If you do not specify the foreignKey property in a hasMany association, it will default to the lowercased name of the owner model plus “_id”, You should amend your User model’s hasMany association as so:

Ext.define('MyApp.model.User', {
/** Model Definition */
hasMany : {
    model : 'MyApp.model.Diploma',
    name : 'diplomas',
    foreignKey : userId /** This is what you're missing */
}
});

Perhaps you will find this blog post useful? http://extjs-tutorials.blogspot.com/2012/05/extjs-hasmany-relationships-rules.html

Some important tips from the blog post (in case the link dies at some point)

• Always put your Proxies in your Models, not your Stores, unless you
  have a very good reason not to *
• Always require your child models if using them in hasMany
  relationships. **
• Always use foreignKey if you want to load the children at will
• Always use associationKey if you return the children in the same
  response as the parent
• You can use both foreignKey and associationKey if you like
• Always name your hasMany relationships
• Always use fully qualified model names in your hasMany relationship
• Consider giving the reader root a meaningful name (other than “data”)
• The child model does not need a belongsTo relationship for the
  hasMany to work

*The store will inherit its model’s proxy, and you can always override it

**To make it easy, and avoid potential circular references, you can require them in app.js

Credit: Neil McGuigan (http://www.blogger.com/profile/14122981831780837323)