Value node vs Model node?

[Former Member]

Hey!!

Sorry about this simple question, but maybe my learning of value node vs model node is wrong. I have thought that the difference is simply you can get results into a model node from a model but not into a value node. But after reading "How to Create Web Dynpro Value Help using CAF Entity Service Method", I realise you can context-bind the value node to the model too? Does it means it can receive the results from the model when it is being "executed"?

Thank you!!

[former_member185086 · Accepted solution]

Hey!!

Sorry about this simple question, but maybe my learning of value node vs model node is wrong. I have thought that the difference is simply you can get results into a model node from a model but not into a value node. But after reading "How to Create Web Dynpro Value Help using CAF Entity Service Method", I realise you can context-bind the value node to the model too? Does it means it can receive the results from the model when it is being "executed"?

Hi Jackson

Yes , It can receive result from the model when it is executed .

Context and node : In simple word It a Placeholder whose main task is to take care of the flow of data across Controllers

If we say flow of data from dataBase to our UI then model node come into role (Then how i will make uses of those data which is there in database, answer is by binding of the model node to value node it means replication of the data from data base .)

and when we say flow of data into Component(Design time Object) then value node come into role it means uses of the data which is in say component controller to the view controller again replication of the data.

but here context is local

For further help read [this|https://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/6d599690-0201-0010-12bb-b9ea3ea32d22]

Best Regards

Satish Kumar

[Former Member · Accepted solution]

Thank you so much!!

That means SAP has the difference: Model Node and Value node is to cater for the Use of direct mapping from the MODEL to the UI? And Value node is just for local manipulation in the Controller?

Thanks!

[pravesh_verma · Accepted solution]

Hi Jackson,

Yes you are corerct!! You got it right!! Model nodes should always be used only when you want your context node (model binded) to interact with the backend. Any modification in the backend will only be done through this model binded node.

However if you have any manipulations required in the controller or the view level then you directly use the value nodes. Values nodes will never have any impact on the backend untill and unless they are binded with the model OR their value is taken at runtime and is sent to backend through some specific logic\ code.

I hope this solves your query. Please consider closing this thread if you think your issue is solved. Or else revert abck if you have ay query!!

Thanks and Regards

Pravesh

[pravesh_verma]

Hi Jackson,

I understand your concern and yes, what you are saying is correct. You can directly bind the value nodes with the model. In such a case when you execute the model,you will get the values in the context value node.

However, I would always advice you to no direct model bind the value node.

We had similar discussion on forum couple of days back, Please have a look to this link. I hope this will help you.

Kindly confirm if your confusion is solved. In acse you have doubts please revert back,

Thanks and Regards

Pravesh

[Former Member]

Hi Jackson,

If I got u right then you want to bind your context to a model. Is it? Then I am afraid it's not practically possible.

Regards.

Rajat

[Former Member]

Hi,

I hope I use the correct terms. I mean to link them up in the same context.

[Former Member]

Hi Jackson,

The basic difference between value and model nodes is: Value nodes keep the data themselves whereas model nodes hold references to another object, the "model instance" and take the attribute values from there. Which also means, that they will put changes from the UI there.

I hope this answers your query.

Regards.

Rajat

[Former Member]

Hi there!

Correct me if I am wrong,

Does that basically means:

If i context-bind a Value-node and a Model-node to a Model, IF I 'execute' the model, Value-node WILL NOT be updated because it keeps value within itself? Only a Model-node will reflect the changes since it is reference linked?