Is it possible to resolve multiple fields in one function? about vesper

[pleerock]

I think you can use lazy initialization pattern and store your loaded data inside resolver class once it requested and reuse this data in any resolver method.

Since resolvers are services, and services are scoped (scoped to request) this "cached" data inside resolver class will persist during a single user request.

[singingwolfboy]

@pleerock: Thanks, but that doesn't actually solve the problem. Rather than one database query per field, I want to make one database query that will return all fields that the GraphQL query requested. Caching the data doesn't solve this problem, it just means that every field won't be queried more than once.

[pleerock]

I want to make one database query that will return all fields that the GraphQL query requested.

by "all fields" do you mean data from multiple tables?

[singingwolfboy]

When I run with ORM logging turned on, and I send this query:

query {
  people {
    name
    homeAddress
  }
}

I get this result:

query: SELECT "Person"."id" AS "Person_id" FROM "person" "Person"
query: SELECT "kvs"."id" AS "kvs_id", "kvs"."key" AS "kvs_key", "kvs"."value" AS "kvs_value", "kvs"."start_on" AS "kvs_start_on", "kvs"."end_on" AS "kvs_end_on", "kvs"."personId" AS "kvs_personId", "person"."id" AS "person_id" FROM "person_kv_string" "kvs" INNER JOIN "person" "person" ON "person"."id"="kvs"."personId" AND ("person"."id" IN ($1) AND COALESCE(kvs.start_on, '-infinity') <= $2 AND COALESCE(kvs.end_on, 'infinity') >= $3) WHERE "kvs"."key" = 'name' ORDER BY kvs.start_on DESC NULLS LAST -- PARAMETERS: [1,"today","today"]
query: SELECT "kvs"."id" AS "kvs_id", "kvs"."key" AS "kvs_key", "kvs"."value" AS "kvs_value", "kvs"."start_on" AS "kvs_start_on", "kvs"."end_on" AS "kvs_end_on", "kvs"."personId" AS "kvs_personId", "person"."id" AS "person_id" FROM "person_kv_string" "kvs" INNER JOIN "person" "person" ON "person"."id"="kvs"."personId" AND ("person"."id" IN ($1) AND COALESCE(kvs.start_on, '-infinity') <= $2 AND COALESCE(kvs.end_on, 'infinity') >= $3) WHERE "kvs"."key" = 'homeAddress' ORDER BY kvs.start_on DESC NULLS LAST -- PARAMETERS: [1,"today","today"]

Notice how the database query for fetching PersonKVString is being executed twice -- once for name and once for homeAddress. Ideally, it should be executed only once, and WHERE "kvs"."key" = 'name' would be replaced with WHERE "kvs"."key" IN ('name', 'homeAddress'). Does that make sense?

[singingwolfboy]

Is it possible to write a custom resolver for an entity, like my Person entity, instead of for a field on that entity? That would solve this problem, as well.