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Session: Get Time Series Entries

To get a range of time series entries, use one of the TimeSeriesFor.Get methods.

  • Include time series data while loading or querying documents, to keep the data locally in the client's session and refrain from unnecessary additional trips to the server.
  • While loading time series entries, you can also Include the series parent document and/or documents referred-to by entry tags.
  • When caching is enabled, time series data is kept in the session cache as well.

TimeSeriesFor.Get​

TimeSeriesFor.Get retrieves a range of entries from a single time series.

  • To retrieve multiple series' data, use the GetMultipleTimeSeriesOperation document-store operation.
  • Retrieved data can be sliced to pages to get time series entries gradually, one custom-size page at a time.

Syntax​

  • There are two TimeSeriesFor.Get methods:
TimeSeriesEntry[] Get(DateTime? from = null, DateTime? to = null,
  int start = 0, int pageSize = int.MaxValue);
//The stongly-typed API is used, to address time series values by name.
TimeSeriesEntry<TValues>[] Get(DateTime? from = null, DateTime? to = null,
int start = 0, int pageSize = int.MaxValue);

  • Parameters

    ParametersTypeDescription
    fromDateTime?Range Start
    toDateTime?Range End
    startintPaging first entry.
    E.g. 50 means the first page would start at the 50th time series entry.
    Default: 0, for the first time-series entry.
    pagesizeintPaging page-size.
    E.g. set pagesize to 10 to retrieve pages of 10 entries.
    Default: int.MaxValue, for all time series entries.

  • Return Values

    • TimeSeriesEntry[] - an array of time series entry classes.
public class TimeSeriesEntry
{
  public DateTime Timestamp { get; set; }
  public double[] Values { get; set; }
  public string Tag { get; set; }
  public bool IsRollup { get; set; }

  public double Value;

  //..
}
  • TimeSeriesEntry<TValues>[] - Time series values that can be referred to by name.

Usage Flow​

  • Open a session.
  • Create an instance of TimeSeriesFor.
  • Call TimeSeriesFor.Get.

Usage Samples​

  • In this sample we retrieve all the entries of a time series, using its parent-document's ID explicitly.
// Get all time series entries
TimeSeriesEntry[] val = session.TimeSeriesFor("users/john", "HeartRates")
  .Get(DateTime.MinValue, DateTime.MaxValue);
  • In this sample we query for a document and get its "Heartrate" time series data.
// Query for a document with the Name property "John" 
// and get its HeartRates time-series values
using (var session = store.OpenSession())
{
  var baseline = DateTime.Today;

  IRavenQueryable<User> query = session.Query<User>()
      .Where(u => u.Name == "John");

  var result = query.ToList();

  TimeSeriesEntry[] val = session.TimeSeriesFor(result[0], "HeartRates")
      .Get(DateTime.MinValue, DateTime.MaxValue);

  session.SaveChanges();
}
  • Here, we check whether a stock's closing-time price is rising from day to day (over three days).
    Since each time series entry contains multiple StockPrice values, we include a sample that uses named time series values to make the code easier to read.
// Use Get without a named type
// Is the stock's closing-price rising?
bool goingUp = false;

using (var session = store.OpenSession())
{
  TimeSeriesEntry[] val = session.TimeSeriesFor("users/john", "StockPrices")
      .Get();

  var closePriceDay1 = val[0].Values[1];
  var closePriceDay2 = val[1].Values[1];
  var closePriceDay3 = val[2].Values[1];

  if ((closePriceDay2 > closePriceDay1)
      &&
      (closePriceDay3 > closePriceDay2))
      goingUp = true;
}