GraphQL Queries

Type definitions

Start with using these GraphQL type definitions that define a simple Movie type with only one property title. The database contains other data, but for now you will start with this simple type definition.

Replace the contents of the type definition editor with the following snippet:

type Movie @node {
  title: String
}

The Generated GraphQL API

The Neo4j GraphQL Library uses the convention of mapping GraphQL types to Neo4j node labels in the property graph model. The single Movie type defined above maps to a Neo4j property graph model with a single node label Movie and a single node property title.

Click on the "Build Schema" button and note that two query field are generated for the Movie type:

In this lesson you will explore the Query.movies query field.

Querying the GraphQL API

The Query.movies query field allow for top-level query access to search for data and begin the data graph traversal from the Movie type/node label (remember that node labels map to GraphQL types defined in the type definitions when using the Neo4j GraphQL Library).

Run the following query in the Neo4j GraphQL Toolbox to see the results of the generated GraphQL API operations.

query MyQuery {
  movies(limit: 10) {
    title
  }
}

{
  "data": {
    "movies": [
      { "title": "Toy Story" },
      { "title": "Jumanji" },
      { "title": "Grumpier Old Men" },
      { "title": "Waiting to Exhale" },
      { "title": "Father of the Bride Part II" },
      { "title": "Heat" },
      { "title": "Sabrina" },
      { "title": "Tom and Huck" },
      { "title": "Sudden Death" },
      { "title": "GoldenEye" }
    ]
  }
}

The Query.movies generated query field takes optional arguments, for example:

The limit argument was used in the example query to limit the number of results. A sort argument can also be added to change the sort order of the results.

query MyQuery {
  movies(limit: 10, sort: { title: ASC }) {
    title
  }
}

Explore the schema

In addition to editing the GraphQL queries in the Query Editor you can use the Explorer feature integrated into the Neo4j GraphQL Toolbox to interactively explore the schema documentation and toggle fields on and off in the selection set.

Filtering With The where Argument

If you expand the where input object in Explorer you can see the various fields available on the input object. These input fields correspond to various string comparison operations with the title field on the Movie type.

You can filter for movies titles that contain a certain substring by creating a where argument against the Movie.title field.

Run this query which searches for any movies with "Matrix" in the title.

GraphQL

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query MyQuery {
  movies(where: { title: { contains: "Matrix" } } ) {
    title
  }
}

JSON

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{
  "data": {
    "movies": [
      { "title": "Matrix Reloaded, The" },
      { "title": "Matrix Revolutions, The" },
      { "title": "Matrix, The" }
    ]
  }
}

Parameters

You can also use GraphQL variables to write queries by passing parameter values in the params.json panel.

1. Enter the following parameter into params.json tab in the Neo4j GraphQL Toolbox.

   json

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   {
     "searchString": "Matrix"
   }

2. Modify the query to accept and use the $searchString parameter.

   GraphQL

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   query MyQuery($searchString: String) {
     movies(where: { title: { contains: $searchString } } ) {
       title
     }
   }

3. Run the query and see the same results as before.