The documentation gives these examples of query definitions. My understanding is items starting with _$ are parameters you can pass to the query.
The only examples I can find of the Query() function inside the transaction processors do not provide parameters.
How can I pass params to my query?
Ala let result = Query('MyGreatQueryReqParam`, name = "john");
As answered on Rocket Chat ...
The buildQuery and Query() methods are covered with examples at the bottom of this doc: https://hyperledger.github.io/composer/latest/api/runtime-api
But the short answer is:
return query('Q1', { inputValue: 'blue' })
Related
The parse documentation explains how to retrieve a parent object when querying for children:
const query = new Parse.Query(Comment);
// Include the post data with each comment
query.include("post");
const comments = await query.find();
But it says nothing about going in the other direction (the natural direction, it seems to me): I want to query for posts, and I want each post to include its array of comments. Is there a way to accomplish this?
You can't retrieve one post and all related comments in a single query unless you use aggregate.
Without using aggregate, you will have to perform two queries:
const post = await (new Parse.Query(Post)).get(postId);
const comments = await (new Parse.Query(Comment)).equalTo('post', post).find();
Hi Everyone I am just trying to learn graphql as I am using Gatsby. I want to know does each field in graphql take an argument or does it need to be defined somehow before. So for example if you visit this link graphql search results
https://graphql.org/swapi-graphql?query=%7B%0A%09allPeople%20%7B%0A%09%20%20people%20%7B%0A%09%20%20%20%20id%0A%20%20%20%20%20%20name%0A%20%20%20%20%20%20birthYear%0A%20%20%20%20%20%20eyeColor%0A%09%20%20%7D%0A%09%7D%0A%7D%0A
If i wanted to limit people by eye color how would I do that. In the docs it seems easy as you would just do something like people(eyecolor: 'brown') but that doesn't seem possible. Am I missing something? I basically want to do a SQL style search for all people where eye color is brown.
Thanks.
Arguments need to be defined in the schema and implemented in the resolver. If you're consuming a 3rd party API (like the link you provided), you're limited to their schema. You can tell by looking at their schema (by clicking Docs on the right side of the page) which fields take arguments. For example, person takes id and personID arguments:
people doesn't take any arguments, as seen in the schema:
If you're building your own schema, you can add arguments to any field, and when you implement the resolver for that field you can use the arguments for logic in that resolver.
If you're working with a schema that you don't control, you'll have to add filtering on the frontend:
const {people} = data.allPeople;
const brownEyedPeople = people.filter(({eyeColor}) => eyeColor === 'brown');
When you start developing in Gatsby and actually pull your data into Gatsby, there will be a filter query option that automatically becomes available in the query arguments.
https://www.gatsbyjs.org/docs/graphql-reference/#filter
You can expect to be able to filter your people by eyeColor by using the below query:
{
allPeople(filter: { eyeColor: { eq: "brown" } }) {
edges {
node {
id
name
birthYear
eyeColor
}
}
}
}
It's possible to pass a query, but apparently not a fragment:
server.use('/graphiql', graphiqlExpress({
endpointURL: '/graphql',
query: `# Welcome to GraphiQL
query PostsForAuthor {
author(id: 1) {
firstName
posts {
title
votes
}
}
}`}));
Update 10/12/2017
It is possible to send fragments along with a query using Apollo's client:
http://dev.apollodata.com/core/fragments.html
This is not a solution to the original question, however; I would like to pass fragments to a graphiql server instance at startup.
by startup do you mean from the server? if so I don't believe that's how fragments are used. my understanding is as follows:
on the server you provide Types (like User)
on the client you query those Types using queries and fragments
for instance, if you provide type User on the server, on the client graphQL you can use fragments to query that type:
graphQL (client)
fragment authorData on AuthorType{
firstName
posts {
title
votes
}
}
query PostsForAuthor {
author(id: 1) {
...authorData
}
}
As you noticed (and as detailed here) GraphiQL takes a query argument:
query: an optional GraphQL string to use as the initial displayed query, if undefined is provided, the stored query or defaultQuery will be used.
If putting a fragment in as the value for that argument doesn't work, then I don't believe there is any way to start with a fragment ... but really why would you even want to? A fragment by itself isn't executable, and the whole idea is to start GraphiQL with a (executable) query.
If all you want is to be able to copy/paste in some text that you use frequently in your queries, a bookmarklet might be a better idea.
I'm querying my service using a url like:
http://a.com:3080/odata/DiscussionVM(6)?$expand=Section,User
on controller method:
[EnableQuery(MaxExpansionDepth = 7)]
public SingleResult<DiscussionVM> GetDiscussionVM([FromODataUri] int key)
{
return SingleResult.Create(db.DiscussionVMs.Where(discussionVM => discussionVM.DiscussionId == key));
}
This works and returns the correct JSON.
However I then run the slightly more advanced query on a different model:
http://a.com:3080/odata/OrganisationVM(30)?&$expand=Categories($expand=Discussions($expand=Section,User))
and controller action:
// GET: odata/OrganisationVM(5)
[EnableQuery(MaxExpansionDepth = 5, AllowedQueryOptions = AllowedQueryOptions.All)]
public SingleResult<OrganisationVM> Get([FromODataUri] int key)
{
return SingleResult.Create(db.OrganisationVMs.Where(organisationVM => organisationVM.OrganisationId == key));
}
this returns the below DiscussionVM JSON:
{
#odata.type: "#Models.DiscussionVM",
DiscussionId: 6,
Section_SectionID: 1005,
User_Id: "4cecc52e-ac3a-4696-ac6c-175af2a6378a",
DateCreated: "2014-12-06T00:00:00Z",
OrgCat_OrganisationCategoryId: 1,
Text: "Dummy section",
Html: null,
IsUserCreated: true,
Organisation_OrganisationId: null,
Positives: null,
Negatives: null,
CommentCount: 1
}
But contains no User or Section object. No error is thrown. The correct objects are queried (profiled) in the database and data including user and section are returned.
I discovred that oData needs the expanded entities to be referenced in its Edm Model.
if not it will stop expanding after the first level, that's why further expands will not work.
Just add your expandable EntitySet to the ODataConventionModelBuilder in your IEdmModel (in MapODataServiceRoute's model config) :
var builder = new ODataConventionModelBuilder();
// ...
builder.EntitySet<Categories>("categories");
// ...
Hope this helps.
From what Brad and I have gathered in this SO answer, it could be a matter of mixing complex types with entity types. Expand plays very well if all your types are entities, but if you mix both, you end up with weird behavior like you and I are having.
If you do mix them, the expand cascade has to start with entity types and end with complex types. The expand chain seems to end where a complex type has an entity type property.
This could come from v3 where a complex type referring to an entity type was flat not supported. It is in V4 but it is not totally clean with WebAPI as we can see.
The lack of documentation and support on the matter makes it difficult to claim this is the absolute truth, but at least it explained my situation and made my stuff work. Hope it helps you too.
I have never seen your $expand syntax before. Where did you get it from? I think you must expand your query the following way:
http://a.com:3080/odata/OrganisationVM(30)?$expand=Categories/Discussions/Section,Categories/Discussions/User
Assuming Odata V4, here are some examples of the standard.
Given the following query:
var query = from item in context.Users // Users if of type TblUser
select new User() // User is the domain class model
{
ID = item.Username,
Username = item.Username
};
How can I re-use the select part of the statement in other queries? I.e.
var query = from item in context.Jobs // Jobs if of type TblJob
select new Job() // Job is the domain class model
{
ID = item.JobId,
User = ReuseAboveSelectStatement(item.User);
};
I tried just using a mapper method:
public User MapUser(TblUser item)
{
return item == null ? null : new User()
{
ID = item.UserId,
Username = item.Username
};
}
With:
var query = from item in context.Users // Users if of type TblUser
select MapUser(item);
But if I do this, then the framework throws an error such as:
LINQ to Entities does not recognize
the method 'MapUser(TblUser)' method,
and this method cannot be translated
into a store expression.
You can't use regular function calls in a query definition like that. LINQ needs expression trees, it can't analyze compiled functions and magically translate that to SQL. Read this for a more elaborate explanation
The techniques used in the cited article are incorporated in linqkit (factoring out predicates) and might be of help, though I'm not sure you can use the same technique for managing projections, which is what you seem to want.
The more fundamental question you should ask yourself here IMHO is whether you really need this extra mapping layer? It seems like you're implementing something that EF is already perfectly capable of doing for you...
Try making your MapUser method static.