I am getting a single entity by using a method fetchEntityByKey, after that I am loading navigation property for the entity by entityAspect.loadNavigationProperty. But loadNavigationProperty always make a call to the server, what I am wondering if I can first check it from cache, if it is exist then get it from there otherwise go the server. How is it possible? Here is my current code
return datacontext.getProjectById(projectId)
.then(function (data) {
vm.project = data;
vm.project.entityAspect.loadNavigationProperty('messages');
});
Here is a function that I encapsulated inside datacontext service.
function getProjectById(projectId) {
return manager.fetchEntityByKey('Project', projectId)
.then(querySucceeded, _queryFailed);
function querySucceeded(data) {
return data.entity;
}
}
Also, how is it possible to load navigation property with some limit. I don't want to have all records for navigation property at once for performance reason.
You can use the EntityQuery.fromEntityNavigation method to construct a query based on an entity and a navigationProperty . From there you can execute the resulting query locally, via the EntityManager.executeQueryLocally method. So in your example once you have a 'project' entity you can do the following.
var messagesNavProp = project.entityType.getProperty("messages");
var query = EntityQuery.fromEntityNavigation(project, messagesNavProp);
var messages = myEntityManager.executeQueryLocally(query);
You can also make use of the the EntityQuery.using method to toggle a query between remote and local execution, like this:
query = query.using(FetchStrategy.FromLocalCache);
vs
query = query.using(FetchStrategy.FromServer);
please take a look here: http://www.breezejs.com/sites/all/apidocs/classes/EntityManager.html
as you can see fetchEntityByKey ( typeName keyValues checkLocalCacheFirst ) also have a third optional param that you can use to tell breeze to first check the manager cache for that entity
hope this helps
Related
I have a oData model with entities : Order, OrderInformation. There is 1 : 1 an association between Order and OrderInformation.
Now in the view, based on a value in OrderInformation, I should hide / display a button.
In the controller, following logic to get the value of OrderInformation->appUrl does not work but I can read the property of entity 'Order'.
Init: function(){
// Not working
var prop = this.getView().getModel().getProperty("/OrderInformations('"+ this._orderId + "')/appUrl");
// Working
var prop = this.getView().getModel().getProperty("/Orders('"+ this._orderId + "')/orderType");
}
In transaction /IWFND/GW_CLIENT, following query gives me correct value
/sap/opu/odata/sap/<<ServiceURL>>/OrderInformations('132123')/appUrl
I also tried with the attachRequestCompleted but still no success.
Init:function(){
var oModel = this.getView().getModel();
oModel.attachRequestCompleted(function(oEvent){
var myval = model.getProperty("/OrderInformations('"+ this._orderId + "')/appUrl");
});
}
Can someone provide any idea what can be going wrong ?
BR
Nilesh
You can use the oModel.read function to trigger a request to the backend, within the success handler you read the result of the response and process the received data
var test = oModel.read("OrderInformations('" + this._orderId + "')", {
success: function(oData, response) {
var appUrl = oData.result.appUrl; //response.data.appUrl also works
// do something
},
error: function (oError) {
// Error handling on failed response
}
});
API reference: https://openui5beta.hana.ondemand.com/#docs/api/symbols/sap.ui.model.odata.ODataModel.html#read
I don't understand this line you wrote:
In the controller, following logic to get the value of
OrderInformation->appUrl does not work but I can read the property of
entity 'Order'.
Order is another Entity with a property and the addressing for this works like described above?
Did you init your model like this:
/sap/opu/odata/sap/<<ServiceURL>>/Order? Is OrderInformation a related entity of Order? If yes extend the read with the Navigation property of the odata service which defines the relationship between the two Entities
I hope this answers you question, if anything left, let me know
Best regards
I am querying the server to get an entity with expand
function _loadIncidents() {
var deffered = Q.defer(),
queryObj = new breeze.EntityQuery().from('Incidents').expand(['Deployments', 'IncidentComments', 'DTasks', 'ExtendedProperties', 'IncidentEvents']);
dataRepository.fetchEntitiesByQuery(queryObj, true).then(function (incidents) {
var query = breeze.EntityQuery.from("DTasks"),
incidentIds = dataRepository.getEntitiesByQuerySync(query);
deffered.resolve();
}, function(err) {
deffered.reject(err);
});
return deffered.promise;
};
I am getting the results and all is fine, how ever when I query breeze cache to get the entities - I am getting empty collection. So when using expand does the expanded entities are added to the cache?
Yes the related entities identified in the expand should be in cache ... if the query is "correct" and the server interpreted your request as you intended.
Look at the payload of the response from the first request. Are the related entities present? If not, perhaps the query was not well received on the server. As a general rule, you want to make sure the data are coming over the wire before wondering whether Breeze is doing the right thing with those data.
I do find myself wondering about the spelling of the items in your expand list. They are all in PascalCase. Are they these the names of navigation properties of the Incident type? Or are they the names of the related EntityTypes? They need to be former (nav property names), not the latter.
I Had problem with the navigation property - as I am not using OData webapi not using EF , there is problem with the navigation properties so for the current time i just wrote
Object.defineProperty(this, 'Deployments', {
get: function () {
return (this.entityAspect && this.entityAspect.entityManager) ?
this.entityAspect.entityManager.executeQueryLocally(new breeze.EntityQuery("Deployments").
where('IncidentID', 'eq', this.IncidentID)) :
[];
},
set: function (value) { //used only when loading incidents from the server
if (!value.results) {
return;
}
var i = 0,
dataRepository = require('sharedServices/dataRepository');
for (i; i < value.results.length; i++) {
dataRepository.addUnchangedEntity('Deployment', value.results[i]);
}
},
enumerable: true
});
I've tried drilling down into the object and looking at the docs but haven't found anything. I've created an entity and I need to assign some properties manually. I see _backingStore and entityAspect on the object... and I know the property names but don't know how to set them via the breeze entity.
In case it matters, I'm creating a new object and then copying properties over from another object to facilitate cloning.
function createDocument() {
var manager = datacontext.manager;
var ds = datacontext.serviceName;
if (!manager.metadataStore.hasMetadataFor(ds)) {
manager.fetchMetadata(ds).then(function () {
return manager.createEntity("Document");
})
}
else {
return manager.createEntity("Document");
}
}
function cloneDocument(doc) {
var clonedDocument = createDocument();
// Copy Properties Here - how?
saveChanges()
.fail(cloneFailed)
.fin(cloneSucceeded);
}
Not knowing what your properties might be, here are two scenarios -
function cloneDocument(doc) {
var clonedDocument = createDocument();
clonedDocument.docId(doc.docId());
clonedDocument.description(doc.description());
saveChanges()
.fail(cloneFailed)
.fin(cloneSucceeded);
}
There are a few things to note here - I am assuming you are using Knockout and needing to set the properties. If you are not using Knockout then you can remove the parans and use equals -
clonedDocument.docId = doc.docId;
I believe this is true for if you are not using Knockout (vanilla js) and if you are using Angular, but I have not used Breeze with Angular yet so bear with me.
And here's another way that works regardless of model library (Angular or KO)
function cloneDocument(doc) {
var manager = doc.entityAspect.entityManager; // get it from the source
// Check this out! I'm using an object initializer!
var clonedDocument = manager.createEntity("Document", {
description: doc.description,
foo: doc.foo,
bar: doc.bar,
baz: doc.baz
});
return clonedDocument;
}
But beware of this:
clonedDocument.docId = doc.docId; // Probably won't work!
Two entities of the same type in the same manager cannot have the same key.
Extra credit: write a utility that copies the properties of one entity to another without copying entityAspect or the key (the id) and optionally clones the entities of a dependent navigation (e.g., the order line items of an order).
I am working on a Hottowel project and I want to format some data passed on from database to Breeze, but it looks like the ctor is not getting registered.
What am I doing wrong?
In datacontext.js:
var manager = configureManager();
function configureManager() {
var mng = new breeze.EntityManager('breeze/data');
breeze.NamingConvention.camelCase.setAsDefault();
model.configureMetadataStore(mng.metadataStore);
return mng;
}
In model.js:
function configureMetadataStore(metadataStore) {
metadataStore.registerEntityTypeCtor
('UserInfo', null, userInfoInitializer);
}
function userInfoInitializer() {
if (this.Email == "")
this.Email = '---';
this.CreateDate = formatDateTime(this.CreateDate);
}
function formatDateTime(DateTime) {
return moment.utc(DateTime).format('DD. MM. YYYY. [у] hh:mm');
}
Datacontext has a reference to model, the data is transferred from database and appears on the screen, but is not formatted. console.log() calls from userInfoInitializer() are not appearing.
When I am constructing an entity, my constructor needs to have an entity to construct. I have not tried your above code but I believe that Breeze passes an entity in and you need to give that entity properties. Using this. MAY work but it is the first thing that stands out to me.
function userInfoInitializer(user) {
if (user.Email == "")
user.Email = "---";
2nd - What is your entity named in your model? Is it UserInfo or just User? You probably already know this but you need to make sure when you are adding a constructor you use the properly named Entity.
3rd - If you are using camelCase then you need to leave the first letter of the property lowercase. Ex . user.email and user.createDate.
Last, I can't tell if you are creating a 'createDate' in the constructor or that is being passed from your model. If it is indeed a property you are creating I would recommend making it an knockout observable or computed property. If it is coming from the database then you need to do something like
if (!user.createDate) { } //set it
Remember that all of the entities being returned from the database will be given that property, so if you have entities that already have a createDate in your example you are overriding that date. If you want to set createDate to now then I would move that into your method where you are creating the object.
I have a SPA application (durandaljs), and I have a specific route where I map the "id" of the entity that I want to fetch.
The template is "/#/todoDetail/:id".
For example, "/#/todoDetail/232" or "/#/todoDetail/19".
On the activate function of viewmodel, I get the route info so I can grab the id. Then I create a new instance of breezejs EntityManager to get the entity with the given id.
The problem is when I call manager.fetchEntityByKey("Todos", id), the EntityManager doesn't have yet the metadata from the server, so it throwing exception "Unable to locate an 'Type' by the name: Todos".
It only works if first I execute a query against the store (manager.executeQuery), prior to calling fetchEntityByKey.
Is this an expected behavior or a bug ? Is there any way to auto-fecth the metadata during instantiation of EntityManager ?
note: I believe it's hard to use a shared EntityManager in my case, because I want to allow the user directly type the route on the browser.
EDIT: As a temporary workaround, I'm doing this:
BreezeService.prototype.get = function (id, callback) {
var self = this;
function queryFailed(error) {
app.showMessage(error.message);
callback({});
}
/* first checking if metadatastore was already loaded */
if (self.manager.metadataStore.isEmpty()) {
return self.manager.fetchMetadata()
.then(function (rawMetadata) {
return executeQuery();
}).fail(queryFailed);
} else {
return executeQuery();
}
/* Now I can fetch */
function executeQuery() {
return self.manager.fetchEntityByKey(self.entityType, id, true)
.then(callback)
.fail(queryFailed);
}
};
You've learned about fetchMetadata. That's important. If you application can begin without issuing a query, you have to use fetchMetadata and wait for it to return before you can perform any operations directly on the cache (e.g., checking for an entity by key in the cache before falling back to a database query).
But I sense something else going on because you mentioned multiple managers. By default a new manager doesn't know the metadata from any other manager. But did you know that you can share a single metadataStore among managers? You can.
What I often do (and you'll see it in the metadata tests in the DocCode sample), is get a metadataStore for the application, write an EntityManager factory function that creates new managers with that metadataStore, and then use the factory whenever I'm making new managers ... as you seem to be doing when you spin up a ViewModel to review the TodoDetail.
Coming from a Silverlight background where I used a lot of WCF RIA Services combined with Caliburn Micro, I used this approach for integrating Breeze with Durandal.
I created a sub folder called services in the App folder of the application. In that folder I created a javascript file called datacontext.js. Here is a subset of my datacontext:
define(function (require) {
var breeze = require('lib/breeze'); // path to breeze
var app = require('durandal/app'); // path to durandal
breeze.NamingConvention.camelCase.setAsDefault();
// service name is route to the Web API controller
var serviceName = 'api/TeamData',
// manager is the service gateway and cache holder
manager = new breeze.EntityManager(serviceName),
store = manager.metadataStore;
function queryFailed(error) {
app.showMessage("Query failed: " + error.message);
}
// constructor overrides here
// included one example query here
return datacontext = {
getSponsors: function (queryCompleted) {
var query = breeze.EntityQuery.from("Sponsors");
return manager
.executeQuery(query)
.then(queryCompleted)
.fail(queryFailed)
}
};
}
Then in your durandal view models you can just require the services/datacontext. For example, here is part of a sample view model from my app:
define(function (require) {
var datacontext = require('services/datacontext');
var ctor = function () {
this.displayName = 'Sponsors',
this.sponsors = ko.observable(false)
};
ctor.prototype.activate = function () {
var that = this;
return datacontext.getSponsors(function (data) { that.sponsors(data.results) });
}
return ctor;
});
This will allow you to not worry about initializing the metadata store in every view model since it is all done in one place.