Step 4: Retrieve data with a GraphQL query - Amazon AppSync
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Step 4: Retrieve data with a GraphQL query

Now that a record exists in your database, you'll get results when you run a query. A query is one of the other fundamental operations of GraphQL. It's used to parse and retrieve information from your data source. In terms of REST APIs, this is similar to the GET operation. The main advantage of GraphQL queries is the ability to specify your application's exact data requirements so that you fetch the relevant data at the right time.

To query your data source

  1. If you haven't already done so, sign in to the Amazon Web Services Management Console and open the AppSync console.

  2. Choose your API from the table.

  3. In the tab to the left, choose Queries.

  4. In the Explorer tab to the left of the table, under query listTodos, expand the getTodo operation:

  5. In the code editor, you should see the operation code:

    query listTodos {
  getTodo(id: "") {
    description
    id
    name
    when
    where
  }

    In (id:""), fill in the value that you saved in the result from the mutation operation. In our example, this would be:

    query listTodos {
  getTodo(id: "abcdefgh-1234-1234-1234-abcdefghijkl") {
    description
    id
    name
    when
    where
  }

  6. Choose Run, then listTodos. The result will appear to the right of the editor. Our example looked like this:

    {
  "data": {
    "getTodo": {
      "description": "I need to buy eggs",
      "id": "abcdefgh-1234-1234-1234-abcdefghijkl",
      "name": "Shopping List",
      "when": "Friday",
      "where": "Home"
    }
  }
}
    Note

    Queries only return the fields you specify. You can deselect the fields you don't need by deleting them from the return field:

    {
    description
    id
    name
    when
    where
  }

    You can also uncheck the box in the Explorer tab next to the field you want to delete.

  7. You can also try the listTodos operation by repeating the steps to create an entry in your data source, then repeating the query steps with the listTodos operation. Here's an example where we added a second task:

    {
  "createtodoinput": {
    "name": "Second Task",
    "when": "Monday",
    "where": "Home",
    "description": "I need to mow the lawn"
  }
}

    By calling the listTodos operation, it returned both the old and new entries:

    {
  "data": {
    "listTodos": {
      "items": [
        {
          "id": "abcdefgh-1234-1234-1234-abcdefghijkl",
          "name": "Shopping List",
          "when": "Friday",
          "where": "Home",
          "description": "I need to buy eggs"
        },
        {
          "id": "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee",
          "name": "Second Task",
          "when": "Monday",
          "where": "Home",
          "description": "I need to mow the lawn"
        }
      ]
    }
  }
}