{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "title": "JSON Table Schema",
  "description": "JSON Table Schema is a specification for describing tabular data.",
  "type": "object",
  "properties": {
    "fields": {
      "type": "array",
      "minItems": 1,
      "items": {
        "type": "object",
        "properties": {
          "name": { "type": "string" },
          "title": { "type": "string" },
          "description": { "type": "string" },
          "type": {
            "enum": [
              "string",
              "number",
              "integer",
              "date",
              "time",
              "datetime",
              "boolean",
              "object",
              "geopoint",
              "geojson",
              "array",
              "duration",
              "any"
            ]
          },
          "rdfType": {"type": "string" },
          "format": { "type": "string" },
          "constraints": {
            "type": "object",
            "properties": {
              "required": { "type": "boolean" },
              "minLength": { "type": "integer" },
              "maxLength": { "type": "integer" },
              "unique": { "type": "boolean" },
              "pattern": { "type": "string" },
              "minimum": {
                "oneOf": [ { "type": "string" }, { "type": "number" } ]
              },
              "maximum": {
                "oneOf": [ {"type": "string"}, {"type": "number"} ]
              },
              "enum": {
                "type": "array",
                "minItems": 1,
                "uniqueItems": true
              }
            }
          }
        },
        "required": ["name"]
      }
    },
    "primaryKey": {
      "oneOf": [ { "type": "string" }, { "type": "array" } ]
    },
    "foreignKeys": {
      "type": "array",
      "items": {
        "type": "object",
        "required": [ "fields", "reference" ],
        "properties": {
          "fields": { "oneOf": [ { "type": "string" }, { "type": "array" } ] },
          "reference": {
            "type": "object",
            "required": [ "resource", "fields" ],
            "properties": {
              "resource": { "type": "string" },
              "fields": { "oneOf": [ { "type": "string" }, { "type": "array" } ] }
            }
          }
        }
      }
    }
  },
  "required": [ "fields" ]
}