I want to be able to filter based on the properties of related models. For example, I have a Class object with a Building object. I want to get a list of classes that take place in a certain building.
This filter
{
"include":"building",
"scope":{
"where":{
"name":"warehouse"
}
}
}
returns all classes, but only includes building if its name is "warehouse". What I want is for the where clause on building name to apply to the whole filter so that I only get the class if it's building has that name.
Is there any way to do what I want?
Thanks!
You can do this in code, see include with filters in the docs.
I'm not sure about the JSON but I think it should look more like this:
"include": {
"relation": "building",
"scope": {
"where": {"name": "warehouse"}
}
}
At the moment this is not possible. The issue has been described in this topic; https://github.com/strongloop/loopback/issues/517
It looks like Strongloop is not going to implement this feature in the near future.
Whenever you want to use it on API CALL , you can follow a model like this one
and adapt it to your context.
//Here (as filter) , we get just the most recent message of a chat
{
"include" : {
"relation" : "messages" ,
"scope" :
{
"order" : "createdAt DESC" ,
"limit":1,
"skip":0
}
}
}
At the moment this is not possible in loopback, but you can use this component for resolve this ploblem. It is an easy to use and works perfectly.
https://www.npmjs.com/package/loopback-component-relation-filter
after you configure the component in the component-config.json file as the component documentation says. You can resolve your problem with.
assuming that the main model is called classes and that it has the relationship called building.
var filter = {
where: {
building:{ name:"warehouse" }
}
}
app.models.classes.find(filter, console.log);
That code only returns the classes when building name is warehouse.
Related
I'm studying spring data for Neo4J and I've seen some examples where you just define a method in the repository interface following some standards (to find by a specific attribute) and it's automatically handled by spring. Ex: findByName.
It works quite straightforward with basic attributes but it doesn't seems to work when the attribute is actually a relationship.
See this example:
public class AcceptOrganizationTask extends AbstractTask {
#Relationship(type="RELATES_TO", direction = "OUTGOING")
private OrganizationInvite invitation;
...
}
In the repository interface I've defined 3 methods (All with the same goal):
List<AcceptOrganizationTask> findAllByInvitation(OrganizationInvite invite);
#Query("MATCH (i:OrganizationInvite)<-[RELATES_TO]-(t:AcceptOrganizationTask) WHERE i={invite} RETURN t")
List<AcceptOrganizationTask> getTaskByInvitation(#Param("invite") OrganizationInvite invite);
AcceptOrganizationTask findByInvitation_Id(Long invitationId);
None of them are able to retrieve the task by its invite property. But if I use use findAll() I can get the object with the property associated to the correct invitation.
Am I missing something ?
Bellow I have the Cypher code generated for this three methods:
findAllByInvitation
MATCH (n:`AcceptOrganizationTask`)
WHERE n.`invitation` = { `invitation_0` }
WITH n MATCH p=(n)-[*0..1]-(m) RETURN p, ID(n)
with params {invitation_0={entityId=15, version=0, createdOn=1484758262374, lastChanged=1484758262374, createUser=null, lastUpdatedBy=null, email=user2#acme.com, randomKey=fc940b14-12c3-4894-b2b4-728e3a6b8036, invitedUser={entityId=11, version=0, createdOn=1484758261450, lastChanged=1484758261450, createUser=null, lastUpdatedBy=null, name=User user2#acme.com, email=user2#acme.com, credentialsNonExpired=true, lastPasswordResetDate=null, authorities=null, authoritiesInDB=[], accountNonExpired=true, accountNonLocked=true, enabled=true, id=11}, id=15}}
getTasksByInvitation
MATCH (i:OrganizationInvite)<-[RELATES_TO]-(t:AcceptOrganizationTask)
WHERE i={invite} RETURN t with params {invite=15}
findByInvitation_Id
MATCH (n:`AcceptOrganizationTask`)
MATCH (m0:`OrganizationInvite`)
WHERE m0.`id` = { `invitation_id_0` }
MATCH (n)-[:`RELATES_TO`]->(m0)
WITH n
MATCH p=(n)-[*0..1]-(m) RETURN p, ID(n)
with params {invitation_id_0=15}
All entities inherit from a common AbstractEntity with and Long id field, annotated with #GraphId.
Am I missing something ?
At the moment derived finder queries support only works to one level of nesting.
We are hoping to add this feature soon in the coming weeks though.
For now you can write a custom #Query to get around this.
I have successfully managed to get this rather ember-unfriendly API result into a parent/child pair of models called 'connector' and 'pin', where the connector is the parent and an array of pins is the children. I have a hasMany('pin') on the connector model and belongsTo('connector') on the pins.
{
"Connector" : {
"ConnectorID" : "2015-11-30T16:34:34.217",
"ConnectorName" : "D38999/20WA98SN"
},
"Pins" : [{
"ConnectorID" : "2015-11-30T16:34:34.217",
"PinName" : "A"
}, {
"ConnectorID" : "2015-11-30T16:34:34.217",
"PinName" : "B"
}, {
"ConnectorID" : "2015-11-30T16:34:34.217",
"PinName" : "C"
}
]
}
So far, all is well, I think. I am now faced with getting all of the data from both to appear on a route called 'connector'. I can't quite wrap my mind around how to chain the promises so that I can get both
this.get('store').findRecord('connector', params.connector_id);
and
this.get('store').findRecord('connector', params.connector_id).findAll(???);
It seems like I am fighting an up-hill battle on this relationship. I wish I could just get Ember to treat the array of pins as it would any other singular data type and get/save the data with the record. Am I think of this correctly?
The answer to "I wish I could just get Ember to treat the array of pins..." comment was solved with
ember g transform array
Tips to this post:
How to represent arrays within ember-data models?.
I am pretty happy with the final code after I cleaned up all of my experiments. I didn't have to call
App.register("transform:array", DS.ArrayTransform);
At least I didn't have to write the call myself.
I've got a data structure fairly similar to the one described on the Loopback HasManyThrough documentation page.
For a given Physician (e.g. id 2), I would like to get all their patients with an appointment AND their appointment date.
I can do a GET operation like this:
GET /physicians/2
with the filter header { "include" : {"relation":"patients"} }
And I do get the physician, and the list of patients, but I lose the appointmentDate of the relation.
Or, I can do a GET operation on the relation table like the documentation shows:
GET /appointments
with the filter header { "include" : {"relation":"patient"}, "where":{"physicianId":2}} }
And I get the the appointments, with the date and the patient embedded, but not the physician details.
I can't seem to be able to combine the two.
Is there a way to get the whole data with one query?
The data would be something like this:
[
"name" : "Dr John",
"appointments" : [ {
"appointmentDate": "2014-06-01",
"patient": {
"name": "Jane Smith",
"id": 1
}
}]
]
One way hack I found is to define the relation twice. Once as a HasManyThrough and once as a HasMany to the appointments table, then I can do something like this:
GET /physicians/2
with the filter header { "include" : {"relation":"appointments","scope":{"include":["patient"]} } }
But that doesn't seem right, or could maybe lead to odd behaviours with the duplicated relation.. but maybe I'm paranoid.
You could include both models
GET /appointments
{ "include": ["patient", "physician"], "where": { "physicianId":2 } }
You will get quite a lot of duplicate data though (details of physician with id 2). I believe, that HasManyThrough relation model was initially not supposed to carry any extra data and therefore, it has some limitations. Here is a related github issue.
like a common joined relation i would like to filter my results based on filtered children in a parent-child relation.
i did this
{"include":{"relation":"children","scope":{"where":{"and":[{"name":"xxx"}]}}}}
that gave me ALL parents and inside them, children filtered by that name.
any clues? thanks
ref:
https://docs.strongloop.com/display/public/LB/Querying+related+models#Queryingrelatedmodels-Usingfiltersparameterswithincludedrelations
As per https://stackoverflow.com/a/32933383/344022 there's nothing officially available yet. There is a fork of the loopback-connector by #DiogoDoreto that does attempt to provide it. I haven't tried it, but if you were to use it you would do the following in a filter:
"where": {
"children": {
"where": {
"name": "xxx"
}
}
}
In Loopback it is easy to include relational objects when querying for data. For example, one can include all the comments that belong to a blog post in a single call using the include filter.
But in my case I want to get data that doesn't have a relation.
I have a User Detail page. On that page a user can choose a username and there's also a dropdown list where a user can choose from what country he is.
So from the client side I do something like:
Country.find().$promise.then(function(countryData) {
$scope.countries = countryData;
});
Player.find().$promise.then(function(playerData) {
$scope.player = playerData;
}
But what if I get more lists that I want to fill? Like, city, state, colors etc.
Then I'd have to make a lot of separate calls.
Is there a way to include all this data in one call, eventhough they have no relation? Something like this:
Player.find({ filter: { include: ["countries", "colors"] } }).$promise.then(function(data) {
// some stuff
}
You may want to try using the Where filter as documented here
An example of this for querying two specific things would be:
Post.find({where: {and: [{title: 'My Post'}, {content: 'Hello'}]}},
function (err, posts) {
...
});
You could create a remote method on one of your models that makes the calls internally and packages them back up for you.
Use some promise library if not using ES6 to wait for all and then return
Model.getAll = function(next) {
var promises = [];
promises.push(Model.app.models.Country.find());
promises.push(Model.app.models.Player.find());
promises.push(Model.app.models.Color.find());
Promise.all(promises)
.then(function(results) {
next(results);
});
}
/**
Register your remote method here
*/
You could create a remote method on one of your models that makes the calls internally and packages them back up for you.
Use some promise library if not using ES6 to wait for all and then return
Model.getAll = function(next) {
var promises = [];
promises.push(Model.app.models.Country.find());
promises.push(Model.app.models.Player.find());
promises.push(Model.app.models.Color.find());
Promise.all(promises)
.then(function(results) {
next(results);
});
}
/**
Register your remote method here
*/
I have problem and try with this solution but i get error "Failed with multiple errors, see details for more information.". It seems like there is bug on Loopback while using promise.all