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.
- In this page:
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
Parameters Type Description from
DateTime?
Range Start to
DateTime?
Range End start
int
Paging 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.pagesize
int
Paging page-size.
E.g. setpagesize
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
.- Either pass
TimeSeriesFor
an explicit document ID,
-or-
Pass it an entity tracked by the session, e.g. a document object returned from session.Query or from session.Load. - Pass
TimeSeriesFor
the time series name.
- Either pass
- 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; }
goingUp = false; // Use Get with a Named type using (var session = store.OpenSession()) { TimeSeriesEntry<StockPrice>[] val = session.TimeSeriesFor<StockPrice>("users/john") .Get(); var closePriceDay1 = val[0].Value.Close; var closePriceDay2 = val[1].Value.Close; var closePriceDay3 = val[2].Value.Close; if ((closePriceDay2 > closePriceDay1) && (closePriceDay3 > closePriceDay2)) goingUp = true; }