Back Links in GraphQL

How-to perform back links in GraphQL with TerminusDB and TerminusCMS

To use this How-To, first clone the Star Wars demo into your team on TerminusCMS. You will then have full access to the data needed for this tutorial

Using a Back Link

Many times when we are looking at an object, we are interested in which objects are pointing to it. In TerminusCMS each object gets a number of extended queries which allows one to discover any objects which point at that object.

Once you have cloned the Star Wars demo, go to the GraphQL query panel and type:

query{
  People(limit:1) {
      █
  }
}

We would like to find the first person in the database, and then find out which starships they are the pilot of. A Starship has a pilot field, and the backlink is automatically constructed as the pilot_of_Starship by TerminusCMS.

query{
   People(limit:1){
     label
     _pilot_of_Starship{
      label
    }
  }
}

This back link will give us back the following:

{
  "data": {
    "People": [
      {
        "label": "Luke Skywalker",
        "_pilot_of_Starship": [
          {
            "label": "X-wing"
          },
          {
            "label": "Imperial shuttle"
          }
        ]
      }
    ]
  }
}

Back linking allows us to focus on modelling our data in a natural way, while still allowing us to follow the graph in either the direction of a field or its opposite without bias.