Amazon RDS helpers in $util.rds

Returns a String by transforming the stringified raw Amazon Relational Database Service (Amazon RDS) Data API operation result format to a more concise string. The returned string is a serialized list of SQL records of the result set. Every record is represented as a collection of key-value pairs. The keys are the corresponding column names.

If the corresponding statement in the input was a SQL query that causes a mutation (for example INSERT, UPDATE, DELETE), then an empty list is returned. For example, the query select * from Books limit 2 provides the raw result from the Amazon RDS Data operation:

{
    "sqlStatementResults": [
        {
            "numberOfRecordsUpdated": 0,
            "records": [
                [
                    {
                        "stringValue": "Mark Twain"
                    },
                    {
                        "stringValue": "Adventures of Huckleberry Finn"
                    },
                    {
                        "stringValue": "978-1948132817"
                    }
                ],
                [
                    {
                        "stringValue": "Jack London"
                    },
                    {
                        "stringValue": "The Call of the Wild"
                    },
                    {
                        "stringValue": "978-1948132275"
                    }
                  ]
            ],
            "columnMetadata": [
                {
                    "isSigned": false,
                    "isCurrency": false,
                    "label": "author",
                    "precision": 200,
                    "typeName": "VARCHAR",
                    "scale": 0,
                    "isAutoIncrement": false,
                    "isCaseSensitive": false,
                    "schemaName": "",
                    "tableName": "Books",
                    "type": 12,
                    "nullable": 0,
                    "arrayBaseColumnType": 0,
                    "name": "author"
                },
                {
                    "isSigned": false,
                    "isCurrency": false,
                    "label": "title",
                    "precision": 200,
                    "typeName": "VARCHAR",
                    "scale": 0,
                    "isAutoIncrement": false,
                    "isCaseSensitive": false,
                    "schemaName": "",
                    "tableName": "Books",
                    "type": 12,
                    "nullable": 0,
                    "arrayBaseColumnType": 0,
                    "name": "title"
                },
                {
                    "isSigned": false,
                    "isCurrency": false,
                    "label": "ISBN-13",
                    "precision": 15,
                    "typeName": "VARCHAR",
                    "scale": 0,
                    "isAutoIncrement": false,
                    "isCaseSensitive": false,
                    "schemaName": "",
                    "tableName": "Books",
                    "type": 12,
                    "nullable": 0,
                    "arrayBaseColumnType": 0,
                    "name": "ISBN-13"
                }
            ]
        }
    ]
}

The util.rds.toJsonString is:

[
  {
    "author": "Mark Twain",
    "title": "Adventures of Huckleberry Finn",
    "ISBN-13": "978-1948132817"
  },
  {
    "author": "Jack London",
    "title": "The Call of the Wild",
    "ISBN-13": "978-1948132275"
  },
]

This is the same as util.rds.toJsonString, but with the result being a JSON Object.