I am playing around with a OData service and I am very confused when to use this
var oModel = new sap.ui.model.odata.ODataModel("proxy/http/services.odata.org/V3/(S(k42qhed3hw4zgjxfnhivnmes))/OData/OData.svc");
this.getView().setModel(oModel);
vs
var oModel = new sap.ui.model.odata.ODataModel("odatserviceurl", true);
var productsModel = new JSONModel();
oModel.read("/Products",
null,
null,
false,
function _OnSuccess(oData, response) {
var data = { "ProductCollection" : oData.results };
productsModel.setData(data);
},
function _OnError(error) {
console.log(error);
}
);
this.getView().setModel(productsModel);
I have two working example using both approach but I am not able to figure out why using read method if I can achieve same with first version. Please explain or guide me to the documentation which can clear my confusion.
Ok, lets start with the models:
JSON Model : The JSON model is a client-side model and, therefore, intended for small datasets, which are completely available on the client. The JSON model supports two-way binding. NOTE: no server side call is made on filtering, searching, refresh.
OData Model : The OData model is a server-side model: the dataset is only available on the server and the client only knows the currently visible rows and fields. This also means that sorting and filtering on the client is not possible. For this, the client has to send a request to the server. Meaning searching/filtering calls odata service again.
Now, lets look at scenarios where we will use these models:
Scenario 1: Showing data to user in a list/table/display form. Data manipulation is limited to searching and filtering. Here, I would use oData model directly to controls as only fetching of data is required.( your method 1) (NOTE: One way binding). Remember here all changes require a call to server.
Scenario 2: I have an application which has multiple inputs, user can edit changes, also some fields are calculated and mandatory. All in all, many user changes are done which may be temporary and user might not want to save them. Here, you dont want to send these temporary changes to backend as yet. You way want to manipulate, validate data before sending. Here, we will use JSON Model after reading data from odata model ( your method 2). Store the changes in local JSON model, validate and manipulate them and finally send the data using Odata create/update. Remember here all changes DO NOT require a call to server as data is present in local JSON MODEL.
Let me know if this helps you. :)
EDIT : Additional Information :
As per your comment :
Documentation says oModel.read' trigger get request but new sap.ui.model.odata.ODataModel("proxy/http/services.odata.org/V3/(S(k42qhed3hw4zgjxfnhivnmes))/OData/OData.svc")` does the same thing so why and when to use oModel.read
Here, is where you misunderstood. The code
new sap.ui.model.odata.ODataModel("proxy/http/services.odata.org/V3/(S(k42qhed3hw4zgjxfnhivnmes))/OData/OData.svc") will NOT send a read/get Request. It calls the odata services and fetches the metadata of the service. A service can have multiple entities.
For example: the service :http://services.odata.org/Northwind/Northwind.svc/ has mutiple entity sets such as Categories, Customers, Employees etc. So, when I declare : new sap.ui.model.odata.ODataModel("http://services.odata.org/Northwind/Northwind.svc/") it will fetch the metadata for service (not actual data). Only when you call the desired entity set, it will fetch the data. The Entity set is specified :
When you call the read method ( like you have specified '/Products')
Bind the entity set name directly to control like to List,Table etc ( items='{/Products}' )
Related
im using a sap Smarttable to display my data from an ABAP Backend server. Additionally im using SmartVariantManagement to apply Variants and make them persistent.
The problem in my Application is the initial Load of the Smarttable. It seems like the table is first loading all the available data without any filters from the inital Variant of my Smartvariantmanagement.
Is there any way to apply the filters of Smartvariantmanagement to the initial Load in the Smarttable?
Or even better: Is it possible to shut down a running odata-read request if i apply a new selection in the smartfilterbar and just run the new one instead?
example 1:
you can avoid the initial request by the smarttable property
enableAutoBinding="false"
you can also set some mandatory fields for filtering, now the user performces an explicit call to the database
example 2:
you can also define a filter in the smarttable function
beforeRebindTable="onBeforeRebindTable"
controller:
onBeforeRebindTable: function (oEvent) {
var oBindingParams = oEvent.getParameter("bindingParams");
oBindingParams.filters.push(new sap.ui.model.Filter("PropertyX", "EQ", "myProperty"));
}
regards
I have a OData model and data is as follows
Here, Under ZRECRUITMENT_TRACERRzSet(1), I have "toCandidates" which is Association and it has item level data.
How can I access it's values in the controller.
I tried using
oModel.getProperty('/ZRECRUITMENT_TRACERRzSet(1)/toCandidates')
But it's not helping.
You need to set the 'expand' property in your binding, so whenever the request is sent to the OData service, the "toCandidates" node will come with the data in the response, and not the URL only. Then your getProperty(...) will give you the data.
Whenever you are binding your data you need to do something like this (for example with ElementBinding):
oMyControl.bindElement({
path: "/ZRECRUITMENT_TRACERRzSet(1)",
parameters: {expand: "toCandidates"}
});
Update:
Using ODATA, How to get the last inserted row in /MySet where MySet.Name = "abc".
I do not want to continuously poll the odata service via model.read(). I know attachChange() or attachDataReceived()methods can be use to get notified automaically. But apart from notification, how to get the 'inserted row'. Also My doubt is how to satisfy the following three conditions here : $top=1, $orderby= Date desc and $filter=NAME eq 'ABC'
The only solution I can think of is to get notified by data inserted via attachDataReceived() and then make a model.read() call with the required filters and additional parameters. Although this would result in these additional 'read' calls.
Original Post Below:
Question: How to pass filters in element binding?
Post: I am using odata service for populating my views.
I want to pass certain filters like $filter=NAME eq 'Scott'
Since I want these parameters to be included only when with odata request for a specific ui-element, I want to include them in bindElement()
specifically something like this
var myFilter = new Array();
myFilter.push(new sap.ui.model.Filter("NAME", sap.ui.model.FilterOperator.EQ, 'Scott'));
var myStandardTile = this.byId("__tile3");
myStandardTile .bindElement("/MySet",{filters:myFilter});
But unfortunately this does not works. When I see the 'network' tab in developer console, Filters are not being added with my request.
You cannot. Neither filter nor sorter nor formatter are supported by element bindings. They are only supported by list and tree bindings.
In my scenario i've a MVC on iis serializing objects from entity framework where i've overridden GetHashCode and Equal methods since the Id of those objects is immutable once committed to the database.
i also have some client, who can't reach the database, but connect to iis to get those entities serialized via json and deserialize them locally using newtonsoft.json.
When i deserialize them in the clients for a second time, to refresh the data in them, i was expecting the existing instances to be updated automatically.
I'm expecting a little too much?
Should i write some clone method to copy properties and check a cache for existing ids?
Did i wrote something wrong in the Equal and GetHashCode methods?
For instance:
I've a blog entity with a title in the database
The client connect to iis
get a json string containing {"Id" : 1, "Name" : "blogName"}
deserialize it and store it locally
add post to the blog in the same way to an observable collection in the class blog i've used client side
Someone or something Change the blog name in the database
The client try to refresh
get the json string containing {"Id" : 1, "Name" : "newBlogName"}
deserialize it to a new instance of class blog, with same id
What's next? copy the new instance name to the old one, ore there's a better way?
Yes, you expect too much. You can attach new entity (because entity framework context doesn't know about this entity, because you get it from somewhere outside dbcontext) and then save it.
Answer here
//This place is where you can deserialize your entity
var existingBlog = new Blog { BlogId = 1, Name = "ADO.NET Blog" };
using (var context = new BloggingContext())
{
context.Blogs.Attach(existingBlog);
// Do some more work...
context.SaveChanges();
}
I think the best solution is to have two database one server side and one client side, with the same shared entity framework but different connection strings, json.net with the keep object reference setted and use the network only to sync the databases and then query it client side.
I have a view model that will always create a new entity (Score); it doesn't need to wait for nor query the repository to know this.
I (currently) want to create the new entity as the page loads and use it to populate the (KnockoutJS) view model.
I believe that the entity manager lazily populates the metadata and have spoofed the behavior I want by making an unnecessary query purely to force the metadata population. The API docs don't cover this:
http://www.breezejs.com/sites/all/apidocs/classes/EntityManager.html#property_metadataStore
Question
Is there a way to force the manager to populate the metadata without issuing a redundant query?
Here's the spoofed code flattened to show its intent:
manager.executeQuery(redundantQuery).then(function(data) {
var viewScore = manager.metadataStore.getEntityType("Score").createEntity();
viewScore.ID(breeze.core.getUuid());
viewScore.Value(57);
ko.applyBindings(viewScore, $ViewScore);
}).fail(function(e){
...
})
I'd be happy with:
manager.metadataStore.then(function() {
})...
Okay, lesson learned.... try it before asking.
This actually works:
manager.metadataStore.fetchMetadata(manager.dataService).then(function () {
var viewScore = manager.metadataStore.getEntityType("Score").createEntity();
viewScore.ID(breeze.core.getUuid());
viewScore.Value(57);
ko.applyBindings(viewScore, $ViewScore);
}).fail(function (e) {
...
});
My only remaining question is why is it necessary to pass the manager.dataService?
A single MetadataStore can store metadata for multiple DataServices. The manager.dataService is simply the 'default' DataService for an EntityManager, there may be others.