IStandardCubeDataset.SetCallback

Syntax

SetCallback(Module: IMetabaseObjectDescriptor; ForeClass: String);

Parameters

Module. Description of the unit where the class is implemented that implements methods of the ISQLCallback interface.

ForeClass. Name of the class used for handling data extraction query generation.

Description

The SetCallback method sets a handler of data extraction query generation for a data source.

Comments

Specify name of the class that implements methods of the ISQLCallback interface in the ForeClass parameter.

To reset the specified handler, set the Module parameter to Null, and the ForeClass to "".

Example

Executing the example requires that the repository contains a standard cube with STD_CUBE identifier and a unit with the CUBE_CALLBACK identifier. The SQLCallback class is implemented in the unit.

Add links to the Cubes and Metabase system assemblies.

Sub UserProc;
Var
    MB: IMetabase;
    Cube: IStandardCube;
    CubeDataset: IStandardCubeDataset;
Begin
    MB := MetabaseClass.Active;
    Cube := MB.ItemById("STD_CUBE").Edit As IStandardCube;
    CubeDataset := Cube.Destinations.Item(0).Datasets.Item(0);
    CubeDataset.SetCallback(MB.ItemById("CUBE_CALLBACK"), "SQLCallback");
    (Cube As IMetabaseObject).Save;
End Sub UserProc;

Public Class SQLCallback: Object, ISQLCallback
    Sub BeforeConstruction(Components: ISQLComponents);
     Var
         i: Integer;
         Select_, From_, Where, GroupBy, Aggregation, OrderBy: String;
     Begin
         Debug.WriteLine("Select_: " + Components.Select_);
         Debug.WriteLine("From_: " + Components.From_);
         Debug.WriteLine("Where: " + Components.Where);
         Debug.WriteLine("GroupBy: " + Components.GroupBy);
         Debug.WriteLine("Aggregation: " + Components.Aggregation);
         Debug.WriteLine("OrderBy: " + Components.OrderBy);
         Debug.WriteLine("SubQuery: " + Components.SubQuery.ToString);
         Debug.WriteLine("ConditionCount: " + Components.ConditionCount.ToString);
         For i := 0 To Components.ConditionCount - 1 Do
             Debug.WriteLine("Condition " + i.ToString + " : " + Components.Condition(i).Condition);
         End For;
         Debug.WriteLine("TableAlias: " + Components.TableAlias);
        //---Modified parts of query
        //Select_ := Components.Select_;
        //...
        //...Modification of Select_
        //...
        //Components.Select_ := Select_;

        //From_ := Components.From_;
        //...
        //...Modification of From_
        //...
        //Components.From_ := From_;

        //Where := Components.Where;
        //...
        //...Modification of Where
        //...
        //Components.Where := Where;

        //GroupBy := Components.GroupBy;
        //...
        //...Modification of GroupBy
        //...
        //Components.GroupBy := GroupBy;

        //Aggregation := Components.Aggregation;
        //...
        //...Modification of Aggregation
        //...
        //Components.Aggregation := Aggregation;

        //OrderBy := Components.OrderBy;
        //...
        //...Modification of OrderBy
        //...
        //Components.OrderBy := OrderBy;
    End Sub BeforeConstruction;

    Sub AfterConstruction(Var SQL: String);
    Begin
        //If required, modification of final query text in SQL variable
        Debug.WriteLine("AFTER: " + SQL);
    End Sub AfterConstruction;
End Class SQLCallback;

On executing the example, the handler of query generation is set for the first cube data source.