使用JSON模式对另一个属性进行验证

Question

In the model below, "category_id" property should be required only if "detail" array is empty.

If "detail" array is not empty, "category_id" property is not required.

How can I do this with JSON Schema?

{
    "description": "Expense model validation.",
    "type": "object",
    "properties": {
        "description": {
            "type": "string"
        },
        "category_id": {
            "type": "string"
        },
        "detail": {
            "type": "array",
            "items": {
                "description": "Expense detail",
                "type": "object",
                "properties": {
                    "description": {
                        "type": "string"
                    }
                },
                "required": [ "description" ]
            }
        }
    },
    "required": [ "description", "category_id" ]
}

Answer 1

You can use anyOf to check that either category_id is present, or detail is present and has at least one item.

{
  "description": "Expense model validation.",
  "type": "object",
  "properties": {
    "description": { "type": "string" },
    "category_id": { "type": "string" },
    "detail": {
      "type": "array",
      "items": {
        "description": "Expense detail",
        "type": "object",
        "properties": {
          "description": { "type": "string" }
        },
        "required": ["description"]
      }
    }
  },
  "required": ["description"],
  "anyOf": [
    { "required": ["category_id"] },
    {
      "properties": {
        "detail": { "minItems": 1 }
      },
      "required": ["detail"]
    }
  ]
}