Conditions on references

In a GraphQL node, you have references that correspond to branches in the graph.

For example, if an item refers to a sales unit, the corresponding field is just a node in the hierarchy and you have to refer to the properties associated with it:

{
    xtremMasterData{
        item{
            query {
                edges {
                    node {
                        id
                        salesUnit{
                            name
                        }
                    }
                }
            }
        }
    }
}

In the previous example, the field salesUnit cannot be displayed as a field. To display the field salesUnit as a field, you have to open a curly bracket section to describe wthe fields to display. In this case, the field is the name.

Sometimes, a reference is not mandatory. For example, if an item is not sold, there will not be be a salesUnit reference and you will see the following result:

{
    "data": {
        "xtremMasterData": {
            "item": {
                "query": {
                    "edges": [
                        {
                            "node": {
                                "id": "101",
                                "name": "TestCottage Pie",
                                "salesUnit": null
                            }
                        }
                    ]
                }
            }
        }
    }
}

On a reference, you cannot directly apply a filter. However, you can apply it to fields found below a reference in the graph hierarchy. This is why you write conditions with nested elements, such as:

{
  xtremMasterData {
    item {
      query(filter: "{salesUnit:{name:'Each'}}") {
        edges {
          node {
            id
            name
            salesUnit {
              name
            }
          }
        }
      }
    }
  }
}

In the previous example, the nested part {salesUnit{ describres how the condition is applied on a nested a property.

It is possible to nest as much levels as required.

The following example is of a deeply nested condition:

{
  xtremSales {
    salesOrder {
      query (filter:"{soldToCustomer:{country:{currency:{name:{_eq:'US Dollar'}}}}}"){
        edges {
          node {
            number
            orderDate
            soldToCustomer {
              country {
                language
                currency {
                  name
                }
              }
            }
          }
        }
      }
    }
  }
}

When a property is a reference, you cannot apply a conditional operator. You can only apply the conditional operator on a property of the corresponding node.

There are two exceptions to this rule: the _eq and _ne operators with null as a value. The following example is a query that lists all the items that have a sales unit:

{
  xtremMasterData {
    item {
      query (filter: "{ salesUnit:{_ne: null}}"){
        edges {
          node {
            id
            salesUnit {
              name
            }
          }
        }
      }
    }
  }
}