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Storing & reading back non-uniform JSON documents via dynamic

This scenario demonstrates how to store and query non-uniform documents via the help of dynamic.


Let us assume we have a document with non-uniform records, presenting temperature sensor data whereby individual records are identified either via the field detector or sensor.

// Our documents with non-uniform structure
var records = new dynamic[]
    new {sensor = "aisle-1", timestamp = "2020-01-21 11:19:19.283", temperature = 21.2},
    new {sensor = "aisle-2", timestamp = "2020-01-21 11:18:19.220", temperature = 21.6},
    new {sensor = "aisle-1", timestamp = "2020-01-21 11:17:19.190", temperature = 21.6},
    new {detector = "aisle-1", timestamp = "2020-01-21 11:16:19.100", temperature = 20.9},
    new {sensor = "aisle-3", timestamp = "2020-01-21 11:15:19.037", temperature = 21.7,},
    new {detector = "aisle-1", timestamp = "2020-01-21 11:14:19.100", temperature = -1.0}

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To store and later read back these records, we create a wrapper type with a dynamic property to present our record.

public class TemperatureData
    public int Id { get; set; }
    public dynamic Values { get; set; }

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We then read and serialize our records into our newly introduced intermediate type and persist an array of its instances via BulkInsert. Lastly, we read back the records, via the non-generic Query extension method, passing in predicates that take into account the non-uniform fields of the source documents. After reading back the data for sensor-1, we calculate the average of its recorded temperatures:

var docs = records.Select(x => new TemperatureData {Values = x}).ToArray();

// Persist our records

using var session = theStore.QuerySession();
// Read back the data for "aisle-1"
dynamic[] tempsFromDb = session.Query(typeof(TemperatureData),
    "where data->'Values'->>'detector' = :sensor OR data->'Values'->>'sensor' = :sensor",
    new {sensor = "aisle-1"}).ToArray();

var temperatures = tempsFromDb.Select(x => (decimal)x.Values.temperature);

Assert.Equal(15.675m, temperatures.Average());
Assert.Equal(4, tempsFromDb.Length);

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Released under the MIT License.