How to query data?

How to query data in Weaviate?

Introduction

  • Weaviate has RESTful API endpoints to query data, but Weaviate’s query language is GraphQL.
  • You can query a Weaviate after you’ve created a schema and populated it with data.

Prerequisites

  1. Connect to a Weaviate instance.
    If you haven’t set up a Weaviate instance yet, check the Getting started guide. In this guide we assume your instance is running at http://localhost:8080 with text2vec-contextionary as vectorization module.
  2. Upload a schema.
    Learn how to create and upload a schema here. In this guide we assume to have a similar schema uploaded with the classes Publication, Article and Author.
  3. Add data.
    Make sure there is data available in your Weaviate instance, you can read how to do this in the previous guide. In this tutorial we assume there are data objects of Publications, Articles and Authors present.

How to get data

1. Define a query.

The easiest GraphQL queries to get data from Weaviate are Get{} queries. Let’s say we want to retrieve all the articles (there title, authors, url and wordCount) that are published by “Wired”, the GraphQL query will look as follows:

    {
      Get {
        Article ( where: {
          operator:Equal,
          valueString:"Wired",
          path: ["inPublication", "Publication", "name"]
        }) {
          title
          url
          wordCount
          hasAuthors{
            ... on Author {
              name
            }
          }
        }
      }
    }

2. Send the query

There are multiple ways to connect to Weaviate’s (GraphQL) API to query data. Raw GraphQL queries can be directly posted in the GraphiQL interface in the Console, but can also be sent via curl, the Python or JavaScript client.

  {
  Get {
    Article  (where: {
      operator:Equal,
      valueString:"Wired",
      path: ["inPublication", "Publication", "name"]
    }){
      title
      url
      wordCount
      hasAuthors{
        ... on Author {
          name
        }
      }
    }
  }
}

  import weaviate

client = weaviate.Client("http://localhost:8080")

get_articles_query = """
  {
    Get {
      Article  (where: {
        operator:Equal,
        valueString:"Wired",
        path: ["inPublication", "Publication", "name"]
      }){
        title
        url
        wordCount
        hasAuthors{
          ... on Author {
            name
          }
        }
      }
    }
  }
"""

query_result = client.query.raw(get_articles_query)
print(query_result)

  const weaviate = require("weaviate-client");

const client = weaviate.client({
  scheme: 'http',
  host: 'localhost:8080',
});

client.graphql
      .get()
      .withClassName('Article')
      .withFields('title url wordCount HasAuthors{ ... on Author { name }}')
      .withWhere({
        operator: 'Equal',
        path: ['inPublication", "Publication", "name'],
        valueString:"Wired"
      })
      .do()
      .then(res => {
        console.log(res)
      })
      .catch(err => {
        console.error(err)
      });

  package main

import (
	"context"
	"fmt"

	"github.com/semi-technologies/weaviate-go-client/v4/weaviate"
	"github.com/semi-technologies/weaviate-go-client/v4/weaviate/filters"
	"github.com/semi-technologies/weaviate-go-client/v4/weaviate/graphql"
)

func main() {
	cfg := weaviate.Config{
		Host:   "localhost:8080",
		Scheme: "http",
	}
	client := weaviate.New(cfg)

	where := filters.Where().
		WithPath([]string{"inPublication", "Publication", "name"}).
		WithOperator(filters.Equal).
		WithValueString("Wired")

	fields := []graphql.Field{
		{Name: "title"},
		{Name: "url"},
		{Name: "wordCount"},
		{Name: "hasAuthors", Fields: []graphql.Field{
			{Name: "... on Author", Fields: []graphql.Field{
				{Name: "name"},
			}},
		}},
	}

	ctx := context.Background()
	result, err := client.GraphQL().Get().
		WithClassName("Article").
		WithFields(fields...).
		WithWhere(where).
		Do(ctx)

	if err != nil {
		panic(err)
	}
	fmt.Printf("%v", result)
}

  package technology.semi.weaviate;

import technology.semi.weaviate.client.Config;
import technology.semi.weaviate.client.WeaviateClient;
import technology.semi.weaviate.client.base.Result;
import technology.semi.weaviate.client.v1.filters.Operator;
import technology.semi.weaviate.client.v1.filters.WhereFilter;
import technology.semi.weaviate.client.v1.graphql.model.GraphQLResponse;
import technology.semi.weaviate.client.v1.graphql.query.fields.Field;

public class App {
    public static void main(String[] args) {
        Config config = new Config("http", "localhost:8080");
        WeaviateClient client = new WeaviateClient(config);

        Field title = Field.builder().name("title").build();
        Field url = Field.builder().name("url").build();
        Field wordCount = Field.builder().name("wordCount").build();
        Field hasAuthors = Field.builder()
                .name("hasAuthors")
                .fields(new Field[]{
                        Field.builder()
                                .name("... on Author")
                                .fields(new Field[]{
                                        Field.builder().name("name").build()
                                }).build()
                }).build();

        WhereFilter where = WhereFilter.builder()
                .path(new String[]{ "inPublication", "Publication", "name" })
                .operator(Operator.Equal)
                .valueString("Wired")
                .build();

        Result<GraphQLResponse> result = client.graphQL().get()
                .withClassName("Article")
                .withFields(title, url, wordCount, hasAuthors)
                .withWhere(where)
                .run();

        if (result.hasErrors()) {
            System.out.println(result.getError());
            return;
        }
        System.out.println(result.getResult());
    }
}

  $ echo '{ 
    "query": "{
      Get {
        Article (where: {
          operator: Equal,
          valueString:\"Wired\",
          path: [\"inPublication\", \"Publication\", \"name\"]
        }){
          title
          url
          wordCount
          hasAuthors{
            ... on Author {
              name
            }
          }
        }
      }
    }"
  }' | curl \
    -X POST \
    -H 'Content-Type: application/json' \
    -d @- \
    http://localhost:8080/v1/graphql

🟢 Click here to try out this graphql example in the Weaviate Console.

  1. View the results
    The results of the previous query looks something like the following in JSON:
    {
 "data": {
   "Get": {
     "Article": [
       {
         "hasAuthors": [
           {
             "name": "Condé Nast"
           },
           {
             "name": "Vince Beise"
           },
           {
             "name": "Vince Beiser"
           },
           {
             "name": "Wired Staff"
           }
         ],
         "title": "The War Vet, the Dating Site, and the Phone Call From Hell",
         "url": "https://www.wired.com/story/the-phone-call-from-hell#intcid=recommendations_wired-homepage-right-rail-popular_1ef3340d-1896-4aff-9f81-0caa132856ac_popular4-1",
         "wordCount": 731
       },
       {
         "hasAuthors": [
           {
             "name": "Matt Simon"
           },
           {
             "name": "Matt Simo"
           }
         ],
         "title": "Not to Ruin the Super Bowl, but the Sea Is Consuming Miami",
         "url": "https://www.wired.com/story/rising-seas-are-coming-for-miamis-super-bowls#intcid=recommendations_default-popular_b3b30847-4aa3-4970-8e77-f7558a7cccd8_popular4-1",
         "wordCount": 586
       },
       {
         "hasAuthors": [
           {
             "name": "Condé Nast"
           },
           {
             "name": "Gregory Barbe"
           }
         ],
         "title": "The Startup That Aims to Decrypt Blockchain for Business",
         "url": "https://wired.com/story/startup-aims-decrypt-blockchain-business/",
         "wordCount": 636
       },
       {
         "hasAuthors": [
           {
             "name": "Lauren Goode"
           },
           {
             "name": "Lauren Good"
           }
         ],
         "title": "The Biggest Apple Maps Change Is One You Can't See",
         "url": "https://www.wired.com/story/apple-maps-redesign#intcid=recommendations_wired-homepage-right-rail-popular_291bba78-5a92-4551-a70b-2b93d1cd3e7a_popular4-1",
         "wordCount": 543
       },
       {
         "hasAuthors": [
           {
             "name": "Will Knight"
           },
           {
             "name": "Will Knigh"
           }
         ],
         "title": "Apple's Latest Deal Shows How AI Is Moving Right Onto Devices",
         "url": "https://www.wired.com/story/apples-deal-shows-ai-moving-devices/",
         "wordCount": 680
       },
       {
         "hasAuthors": [
           {
             "name": "Condé Nast"
           }
         ],
         "title": "Traveling for the Holidays? Here's How to Not Get Sick",
         "url": "https://wired.com/story/traveling-for-the-holidays-heres-how-to-not-get-sick/",
         "wordCount": 608
       },
       {
         "hasAuthors": [
           {
             "name": "Graeme Mcmillan"
           },
           {
             "name": "Graeme Mcmilla"
           }
         ],
         "title": "Sanders and Warren's Big Debate Dust-Up Tops This Week's Internet News Roundup",
         "url": "https://www.wired.com/story/internet-week-253/",
         "wordCount": 364
       },
       {
         "hasAuthors": [
           {
             "name": "Condé Nast"
           },
           {
             "name": "Michael Hard"
           },
           {
             "name": "Laura Mallonee"
           },
           {
             "name": "Michael Hardy"
           }
         ],
         "title": "The Neveda Town Where Storm Area 51 Sort Of Happened",
         "url": "https://www.wired.com/story/rachel-nevada-area-51/",
         "wordCount": 511
       },
       {
         "hasAuthors": [
           {
             "name": "Laura Mallonee"
           },
           {
             "name": "Laura Mallone"
           },
           {
             "name": "Chris Colin"
           },
           {
             "name": "Adam Rogers"
           }
         ],
         "title": "Homelessness in the Living Rooms of the Rich",
         "url": "https://www.wired.com/story/san-francisco-shelters-living-room/",
         "wordCount": 502
       }
     ]
   }
 },
 "errors": null
}

Next steps

More resources

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  1. Frequently Asked Questions. Or,
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