Metadata

Rich Data Services has the ability to capture extensive knowledge around the data, such as provenance, extended column/variable information (e.g. plain labels, definitions, questions, concepts), classifications (code/value labels), and other custom properties. This metadata is an essential part to the application and improve the querying, formatting, and packaging services of RDS. The metadata can be injected and returned alongside the data in JSON, or directly queried using dedicated metadata services. This section will cover the ability to query the metadata by itself.

Rich Data Services has two primary metadata resources, variables and classifications. When queried together they will come back like this.

{
    "metadata": {
        "variables": {                              // The variables object will contain resources (an array of variables) and info (information about how they are paginated)
            "resources": [
                {
                    "id": "var",					// Variable metadata
                    "name": "var",
                    "index": 5,
                    "storageType": "NUMERIC",
                    "displayType": "NUMERIC",
                    "width": 1,
                    "classification": "varClass"	// This is a reference, using the classification ID, to the classification that the variable uses
                }
            ],
            "info": {
                "limit": 1,
                "offset": 4,
                "more": true,
                "count": 67
            }
        },
        "classifications": {
            "resources": [
                {
                    "id": "varClass",				// The Classification that is being referenced by "var" it has three codes, 1, 2, and 3. 
                    "codes": {
                        "resources": [
                            {
                                "value": "1",
                                "label": "METROPOLITAN AREA"
                            },
                            {
                                "value": "2",
                                "label": "TOWN OR CITY"
                            },
                            {
                                "value": "3",
                                "label": "OPEN COUNTRY"
                            }
                        ],
                        "info": {					// information about how the codes are paginated (or not) 
                            "codeLimit": 100,
                            "codeOffset": 0,
                            "count": 3,
                            "moreCodes": false
                        }
                    }
                }
            ],
            "info": {								// information about how the classifications are paginated (or not)
                "limit": 100,
                "offset": 0,
                "codeLimit": 100,
                "codeOffset": 0,
                "more": false,
                "count": 1
            }
        }
    }
}

For more information on querying classifications and variables visit the pages below.