{
  "id": "planets",
  "title": "Planet",
  "description": "A list of planets",
  "primaryKey": ["name"],
  "type": "object",
  "properties": {
    "name": {
      "type": "string",
      "description": "Unique planet name"
    },
    "title": {
      "type": "string",
      "description": "The display-label of the planet"
    },
    "type": {
      "description": "What type of planet is this?",
      "type": "string"
    },
    "diameter": {
      "description": "The diameter of the planet, in metres",
      "type": "number"
    },
    "color": {
      "description": "What color is this planet?",
      "type": "string"
    },
    "url": {
      "type": "string",
      "description": "Further reading available here!"
    },
    "tags": {
      "type": "array",
      "items": {
        "type": "string"
      }
    },

    "moons": {
      "type": "array",
      "description": "Moons go around planets.",
      "items": {
        "type": "object",
        "properties": {
          "title": {
            "type": "string",
            "description": "The display-label of the moon"
          },
          "discoveredBy": {
            "type": "string",
            "description": "Name of the person who discovered the moon"
          },
          "discoveryYear": {
            "type": "integer",
            "description": "Year the moon was discovered (e.g. 1804)"
          },
          "craters": {
            "type": "array",
            "description": "Moons have craters",
            "items": {
              "type": "object",
              "properties": {
                "title": {
                  "type": "string",
                  "description": "The display-label of the crater"
                },
                "diameter": {
                  "type": "integer",
                  "description": "Diameter of the crater, in metres"
                }
              },
              "required": ["name", "title"]
            }
          }
        },
        "required": ["name", "title"]
      }
    }

  },
  "required": ["name", "title"]
}