Downloading Breeze Navigation Properties for Offline Use

Question

Downloading Breeze Navigation Properties for Offline Use

I am currently utilizing the most recent versions of Angular, breeze, and EF.

Within the client environment, I am working on creating a sophisticated object named Quote that is associated with a job. This Quote includes a QuoteMeasure, which in turn contains a navigation property called measure:

var quote = em.createEntity("Quote", { id: breeze.core.getUuid() }),
quoteMeasure,
measure;
measure = _getMeasureFromLookups(4);
quoteMeasure = em.createEntity("QuoteMeasure", { id: breeze.core.getUuid(), quoteId: quote.id });

I have attempted the following approach which triggers a query to the server:

quoteMeasure.measureId = measure.id;
quoteMeasure.entityAspect.loadNavigationProperty("measure").then(function () {
    console.log(quoteMeasure.measure);
});
quote.quoteMeasures.push(quoteMeasure);
job.quotes.push(quote);

directed to the URL /Breeze/Data/Measure?$filter=Id%20eq%204&

This URL, however, does not exist. I am interested in manually setting the navigation property as it pertains to static data that was previously obtained through a breeze query on the server:

    [HttpGet]
    public object Lookups()
    {
        var measures = UnitOfWork.MeasureRepository.Get(null, q => q.OrderBy(m => m.Ordinal)).ToList();
        return new { measures = measures };
    }

The function _getMeasureFromLookups is designed to retrieve the previously stored measure. I would prefer to assign it in this manner:

quoteMeasure.measure = measure;

However, I am encountering a cryptic error on the client:

Error: A is undefined M@//llhst/X/Scripts/breeze.min.js:1 d/f.set@//llhst/X/Scripts/breeze.min.js:5 _createNewQuote@//llhst/X/Scripts/app/services/jobService.js:76

This issue appears to be related to downloading a complete tree of objects via the lookup, rather than focusing on an individual measure entity. The Breeze documentation discusses 'Omitting navigation properties' here, but fails to provide clear instructions on how to implement this.

Therefore, my query is centered around the best practices for loading navigation property data offline. How can the above code sample be adjusted to function correctly?

javascript entity-framework angularjs breeze

Answer 1

Answer №1

To meet your requirements appropriately, you can create the quote and quoteMeasure entities in the following manner:

var quote = em.createEntity("Quote", { id: breeze.core.getUuid() });

//The assignment quoteId: quote.id is equivalent to quote.quoteMeasures.push(quoteMeasure)
//No need to add it again to the collection
var quoteMeasure = em.createEntity("QuoteMeasure", { id: breeze.core.getUuid(), quoteId: quote.id });

var measure = _getMeasureFromLookups(4);

quoteMeasure.measure = measure;

//or
//quoteMeasure.measureId = measure.id

//Your _getMeasureFromLookups function should resemble this
function _getMeasureFromLookups(measureId) {
  //getEntityByKey will fetch Measure from the client cache
  return em.getEntityByKey('Measure', measureId);
}

Invoking loadNavigationProperty will trigger a query to the server.

The section on 'Omitting navigation properties' explains how you can exclude the principal side of the association. For instance, in your EF model, if you do not want a Quote to navigate to all QuoteMeasures, you can do the following:

//EF Model on Server
public class Quote {

  //Simply remove or comment out this collection navigation property
  //public virtual ICollection<QuoteMeasure> QuoteMeasures { get; set; }
}

I hope this clarifies things for you.

Answer 2

To meet your requirements appropriately, you can create the quote and quoteMeasure entities in the following manner:

var quote = em.createEntity("Quote", { id: breeze.core.getUuid() });

//The assignment quoteId: quote.id is equivalent to quote.quoteMeasures.push(quoteMeasure)
//No need to add it again to the collection
var quoteMeasure = em.createEntity("QuoteMeasure", { id: breeze.core.getUuid(), quoteId: quote.id });

var measure = _getMeasureFromLookups(4);

quoteMeasure.measure = measure;

//or
//quoteMeasure.measureId = measure.id

//Your _getMeasureFromLookups function should resemble this
function _getMeasureFromLookups(measureId) {
  //getEntityByKey will fetch Measure from the client cache
  return em.getEntityByKey('Measure', measureId);
}

Invoking loadNavigationProperty will trigger a query to the server.

The section on 'Omitting navigation properties' explains how you can exclude the principal side of the association. For instance, in your EF model, if you do not want a Quote to navigate to all QuoteMeasures, you can do the following:

//EF Model on Server
public class Quote {

  //Simply remove or comment out this collection navigation property
  //public virtual ICollection<QuoteMeasure> QuoteMeasures { get; set; }
}

I hope this clarifies things for you.

Answer 3

Answer №2

It appears that the issue stemmed from forgetting to include the following lines:

        Configuration.ProxyCreationEnabled = false;
        Configuration.LazyLoadingEnabled = false;

The absence of these lines resulted in all navigation properties and their related properties being preloaded, leading to the elusive error mentioned earlier. No further changes were necessary to resolve the problem and the code now functions correctly.

Answer 4

It appears that the issue stemmed from forgetting to include the following lines:

        Configuration.ProxyCreationEnabled = false;
        Configuration.LazyLoadingEnabled = false;

The absence of these lines resulted in all navigation properties and their related properties being preloaded, leading to the elusive error mentioned earlier. No further changes were necessary to resolve the problem and the code now functions correctly.

Answer 5

Answer №3

EntityAspect.loadNavigationProperty()

will always trigger a server request. To prevent multiple requests and load properties without separate calls, opt for Eager loading in EF.

If you encounter null properties upon Breeze fetch and wish to avoid multiple loadNavigationProperty calls, consider utilizing the EntityQuery.expand() method. This allows you to specify which properties to load

Answer 6

EntityAspect.loadNavigationProperty()

will always trigger a server request. To prevent multiple requests and load properties without separate calls, opt for Eager loading in EF.

If you encounter null properties upon Breeze fetch and wish to avoid multiple loadNavigationProperty calls, consider utilizing the EntityQuery.expand() method. This allows you to specify which properties to load

Downloading Breeze Navigation Properties for Offline Use

Answer №1

Answer №2

Answer №3

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