JSonSchema中允许1个patternProperty的单个实例

Question

I have a JsonSchema looking like this

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "additionalProperties": false,
    "definitions": {},
    "id": "http://example.com/example.json",
    "patternProperties": {
        "^[0-9]$": {
....
....
....
        }
     }
}

What I want this Schema to validate is, if there is a JSON string with 0 or 1 of this patternProperty

So for example

{
   "0":{}
}

is a right output

{
}

is also a right output

{
   "0":{},
   "1":{}
}

would be a wrong output even though the patternProperty matches of both, but there is more than 1 node

Is this somehow possible with JSonSchema?

Answer 1

You can use maxProperties and minProperties . If you want exactly one property you can do this:

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "additionalProperties": true,
  "patternProperties": {
    "[a-z]": {}
  },
  "maxProperties": 1,
  "minProperties": 1
}