TAtlasAnalytics

FieldIndex method

class function FieldIndex(Source: TAtlasTable; const Name: string): Integer; static;

Returns the index of the column called Name, compared without regard to case. Raises EAtlasAnalyticsError A source table is required for nil and Unknown field: Name when there is no such column.

Sales.SetFilter('West', TAtlasAnalytics.FieldIndex(Sales, 'region'));

Select method

class function Select(Source: TAtlasTable; const Fields: array of string; const Filters: array of TAtlasFilter): TAtlasTable; static;

Returns the listed columns (all columns, in source order, when Fields is empty) of the rows that match every filter, in view order. Result columns keep the source names, kinds and widths and are read-only. Raises EAtlasAnalyticsError for a nil source, an unknown field, an out-of-range operator or afContains on a non-text column; raises EAtlasDataError for a filter value that does not fit its column and for a field listed twice.

Rows := TAtlasAnalytics.Select(Sales, ['Region', 'Revenue'],
  [TAtlasFilter.Create('Revenue', '10000', afGreater)]);

Aggregate method

class function Aggregate(Source: TAtlasTable; const Dimensions: array of string; const Measures: array of TAtlasMeasure): TAtlasTable; static;

Groups the rows by the exact text of the dimension columns (so East and east are separate groups), in first-seen order, and returns one row per group: the dimension columns, named as you passed them and with the source kinds, then one ackNumber column per measure named by its caption. With no dimensions it returns one total row. Values are written in invariant format (12216.6666666667). Raises EAtlasAnalyticsError for a nil source, no measures (At least one measure is required), an unknown field (including an empty field for a measure other than amCount), a numeric measure on a non-numeric column (Numeric measure requires a numeric field) and sum overflow. Raises EAtlasDataError when a caption is empty or two result columns have the same name (compared without case). Filter first with Select if you need both.

Totals := TAtlasAnalytics.Aggregate(Sales, ['Region'],
  [TAtlasMeasure.Create('Revenue', 'Revenue', amSum)]);

DatasetJSON method

class function DatasetJSON(Source: TAtlasTable): string; static;

Returns the current view as the version 1 dataset JSON read by the web example: fields is an array of {"name", "kind"} objects with kinds text, number, boolean and date, and rows is an array of arrays in field order. Empty cells become null, numbers are JSON numbers (a whole number is written with .0, for example 18000.0), booleans are true or false, and text and dates (YYYY-MM-DD) are strings. Raises EAtlasAnalyticsError for a nil source.

{"version":1,"fields":[{"name":"Region","kind":"text"},{"name":"Revenue","kind":"number"}],"rows":[["East",18000.0],["West",null]]}

Totals per region

Revenue and order count per region, printed to the console.

uses System.SysUtils, Atlas.Data, Atlas.Analytics;

procedure PrintRegionTotals(Sales: TAtlasTable);
var
  Totals: TAtlasTable;
  I: Integer;
begin
  Totals := TAtlasAnalytics.Aggregate(Sales, ['Region'], [
    TAtlasMeasure.Create('Revenue', 'Revenue', amSum),
    TAtlasMeasure.Create('', 'Orders', amCount)]);
  try
    for I := 0 to Totals.RowCount - 1 do
      Writeln(Totals.Cell(0, I), ': ', Totals.Cell(1, I), ' from ', Totals.Cell(2, I), ' orders');
  finally
    Totals.Free;
  end;
end;

Export the dataset JSON

Writes the table in the format the browser dashboard and the ASP.NET example read.

uses System.SysUtils, System.IOUtils, Atlas.Data, Atlas.Analytics;

procedure ExportDataset(Sales: TAtlasTable; const FileName: string);
begin
  TFile.WriteAllText(FileName, TAtlasAnalytics.DatasetJSON(Sales), TEncoding.UTF8);
end;