DashboardFederationDataSource Class
A federated data source that retrieves data from different data sources.
Namespace: DevExpress.DashboardCommon
Assembly: DevExpress.Dashboard.v20.2.Core.dll
NuGet Packages: DevExpress.Dashboard.Core, DevExpress.WindowsDesktop.Dashboard.Core
Declaration
public class DashboardFederationDataSource :
FederationDataSourceBase,
IDashboardDataSource,
IDashboardComponent,
IComponent,
IDisposable,
ISupportInitialize,
ISupportPrefix,
IDashboardDataSourceInternal,
ICloneable<DashboardFederationDataSource>,
IAssignable<DashboardFederationDataSource>,
IQueryDataSource<QueryNode>,
IExternalSchemaConsumerRemarks
You can create a query that combines multiple data sources to provide uniform access. This query forms the federated data source which operates with the source-specific query language, translates the queries, and processes the results to supply a dashboard with data. A federated data source does not support OLAP data sources.
Create a DashboardFederationDataSource instance and add it to the Dashboard.DataSources collection.
The data source obtains its data from federated queries contained in the Queries collection.
Note
In Async mode, if the FederationDataSource includes the DashboardObjectDataSource, make sure that the DashboardObjectDataSource gets data in the AsyncDataLoading event handler and do not call the DashboardObjectDataSource.Fill and FederationDataSource.Fill methods.
Example
This example demonstrates how to bind a dashboard to a federated data source created at runtime. The following data sources are used to create the Data Federation:
- SQL data source connected to the SQLite database
- Excel data source
- Object data source
- JSON Data Source
The example demonstrates the following query types you can use to federate existing data sources:
- Join
- Union and UnionAll
- Transformation
Add the created DashboardFederationDataSource instance to the Dashboard.DataSources collection. The data source obtains its data from federated queries contained in the Queries collection.
Create Join Query Type
using DevExpress.DashboardCommon;
using DevExpress.DataAccess.DataFederation;
using DevExpress.XtraEditors;
// ...
namespace DataFederationExample {
public partial class Form1 : XtraForm {
// ...
private static DashboardFederationDataSource CreateFederatedDataSourceJoin(DashboardSqlDataSource sqliteDataSource, DashboardExcelDataSource exceldataSource, DashboardObjectDataSource objectDataSource) { DashboardFederationDataSource federationDS = new DashboardFederationDataSource("Federated Data Source (JOIN)");
Source sqlSource = new Source("sqlite", sqliteDataSource, "SQLite Orders");
Source excelSource = new Source("excel", exceldataSource, "");
Source objectSource = new Source("object", objectDataSource, "");
#region Use API to join SQL, Excel, and Object Data Sources in a Query
SelectNode mainQueryCreatedByApi = new SelectNode();
mainQueryCreatedByApi.Alias = "FDS-Created-by-API";
SourceNode sqlSourceNode = new SourceNode(sqlSource, "SQLite Orders");
SourceNode excelSourceNode = new SourceNode(excelSource, "ExcelDS");
SourceNode objectSourceNode = new SourceNode(objectSource, "ObjectDS");
mainQueryCreatedByApi.Root = sqlSourceNode;
mainQueryCreatedByApi.Expressions.Add(new SelectColumnExpression() { Name = "SalesPerson", Node = objectSourceNode });
mainQueryCreatedByApi.Expressions.Add(new SelectColumnExpression() { Name = "Weight", Node = objectSourceNode });
mainQueryCreatedByApi.Expressions.Add(new SelectColumnExpression() { Name = "CategoryName", Node = excelSourceNode });
mainQueryCreatedByApi.Expressions.Add(new SelectColumnExpression() { Name = "ProductName", Node = excelSourceNode });
mainQueryCreatedByApi.Expressions.Add(new SelectColumnExpression() { Name = "OrderDate", Node = sqlSourceNode });
mainQueryCreatedByApi.Expressions.Add(new SelectColumnExpression() { Name = "ShipCity", Node = sqlSourceNode });
mainQueryCreatedByApi.Expressions.Add(new SelectColumnExpression() { Name = "ShipCountry", Node = sqlSourceNode });
mainQueryCreatedByApi.Expressions.Add(new SelectColumnExpression() { Name = "Extended Price", Node = excelSourceNode });
mainQueryCreatedByApi.SubNodes.Add(new JoinElement(excelSourceNode, JoinType.Inner, "[ExcelDS.OrderID] = [SQLite Orders.OrderID]"));
mainQueryCreatedByApi.SubNodes.Add(new JoinElement(objectSourceNode, JoinType.Inner, "[ObjectDS.SalesPerson] = [ExcelDS.Sales Person]"));
#endregion
#region Use NodedBuilder to join SQL, Excel, and Object Data Sources in a Query
SelectNode mainQueryCreatedByNodeBuilder =
sqlSource.From()
.Select("OrderDate", "ShipCity", "ShipCountry")
.Join(excelSource, "[excel.OrderID] = [sqlite.OrderID]")
.Select("CategoryName", "ProductName", "Extended Price")
.Join(objectSource, "[object.SalesPerson] = [excel.Sales Person]")
.Select("SalesPerson", "Weight")
.Build("FDS-Created-by-NodeBulder");
#endregion
federationDS.Queries.Add(mainQueryCreatedByApi);
federationDS.Queries.Add(mainQueryCreatedByNodeBuilder);
federationDS.CalculatedFields.Add("FDS-Created-by-NodeBulder", "[Weight] * [Extended Price] / 100", "Score");
federationDS.Fill(new DevExpress.Data.IParameter[0]);
return federationDS;
}
// ...
}
}
Create Transformation Query Type
using DevExpress.DashboardCommon;
using DevExpress.DataAccess.DataFederation;
using DevExpress.XtraEditors;
// ...
namespace DataFederationExample {
public partial class Form1 : XtraForm {
// ...
private static DashboardFederationDataSource CreateFederatedDataSourceTransform(DashboardJsonDataSource jsonDataSource) {
DashboardFederationDataSource federationDS = new DashboardFederationDataSource("Federated Data Source (Transformation)");
Source jsonSource = new Source("json", jsonDataSource, "");
SourceNode sourceNode = new SourceNode(jsonSource);
TransformationNode defaultNode = new TransformationNode(sourceNode) {
Alias = "Default",
Rules = { new TransformationRule { ColumnName = "Products", Unfold = false, Flatten = false } }
};
TransformationNode flattenNode = new TransformationNode(sourceNode) {
Alias = "Flatten",
Rules = { new TransformationRule { ColumnName = "Products", Alias = "Product", Unfold = true, Flatten = true } }
};
TransformationNode unfoldNode = new TransformationNode(sourceNode) {
Alias = "Unfold",
Rules = { new TransformationRule { ColumnName = "Products", Alias = "Product", Unfold = true, Flatten = false } }
};
federationDS.Queries.Add(defaultNode);
federationDS.Queries.Add(flattenNode);
federationDS.Queries.Add(unfoldNode);
return federationDS;
}
// ...
}
}
Create Union and UnionAll Query Types
using DevExpress.DashboardCommon;
using DevExpress.DataAccess.DataFederation;
using DevExpress.XtraEditors;
// ...
namespace DataFederationExample {
public partial class Form1 : XtraForm {
// ...
private static DashboardFederationDataSource CreateFederatedDataSourceUnion(DashboardSqlDataSource sqliteDataSource, DashboardExcelDataSource exceldataSource) {
DashboardFederationDataSource federationDS = new DashboardFederationDataSource("Federated Data Source (UNION)");
Source sqlSource = new Source("sqlite", sqliteDataSource, "SQLite Orders");
Source excelSource = new Source("excel", exceldataSource);
UnionNode queryUnionAll = sqlSource.From().Select("OrderID", "OrderDate").Build("OrdersSqlite")
.UnionAll(excelSource.From().Select("OrderID", "OrderDate").Build("OrdersExcel"))
.Build("OrdersUnionAll");
UnionNode queryUnion = sqlSource.From().Select("OrderID", "OrderDate").Build("OrdersSqlite")
.Union(excelSource.From().Select("OrderID", "OrderDate").Build("OrdersExcel"))
.Build("OrdersUnion");
federationDS.Queries.Add(queryUnionAll);
federationDS.Queries.Add(queryUnion);
federationDS.Fill(new DevExpress.Data.IParameter[0]);
return federationDS;
}
// ...
}
}