Object Types

The schema should define any named object types which will be used as the types of collection row sets, or procedure inputs or outputs.

An object type consists of a name and a collection of named fields. Each field is defined by its type, and any arguments.

Note: field arguments are only used in a query context. Objects with field arguments cannot be used as input types, and fields with arguments cannot be used to define column mappings, or in nested field references.

To define an object type, add an ObjectType to the object_types field of the schema response.

Example

{
  "object_types": {
    "coords": {
      "description": "Latitude and longitude",
      "fields": {
        "latitude": {
          "description": "Latitude in degrees north of the equator",
          "arguments": {},
          "type": {
            "type": "named",
            "name": "Float"
          }
        },
        "longitude": {
          "description": "Longitude in degrees east of the Greenwich meridian",
          "arguments": {},
          "type": {
            "type": "named",
            "name": "Float"
          }
        }
      }
    },
    ...
  },
  ...
}

Extended Example

Object types can refer to other object types in the types of their fields, and make use of other type structure such as array types and nullable types.

In the context of array types, it can be useful to use arguments on fields to allow the caller to customize the response.

For example, here we define a type widget, and a second type which contains a widgets field, parameterized by a limit argument:

{
  "object_types": {
    "widget": {
      "description": "Description of a widget",
      "fields": {
        "id": {
          "description": "Primary key",
          "arguments": {},
          "type": {
            "type": "named",
            "name": "ID"
          }
        },
        "name": {
          "description": "Name of this widget",
          "arguments": {},
          "type": {
            "type": "named",
            "name": "String"
          }
        }
      }
    },
    "inventory": {
      "description": "The items in stock",
      "fields": {
        "widgets": {
          "description": "Those widgets currently in stock",
          "arguments": {
            "limit": {
              "description": "The maximum number of widgets to fetch",
              "argument_type": {
                "type": "named",
                "name": "Int"
              }
            }
          },
          "type": {
            "type": "array",
            "element_type": {
              "type": "named",
              "name": "widget"
            }
          }
        }
      }
    }
  },
  ...
}

See also