Creating a Multidimensional Data Iterator

Contents

Description

Consider creating a multidimensional data iterator. A special feature of this iterator is its ability to be used for several dimensions and iterations will be executed only by points containing data. The data iterator use enables the user to reduce metamodel calculation time.

Requirements

Executing the example requires that the repository contains a modeling container with the MS identifier containing a metamodel with the METAMODEL_MULTIDIMITERATOR identifier. A data source for this container is a time series database containing time series attributes with the CITY and INDICATOR identifiers. Those attributes should be of the Link to dictionary type.

Add links to the Cubes, Dal, Dimensions, Metabase, Ms, and Rds system assemblies.

Example

Sub UserProc;
Var
    mb: IMetabase;
    MsKey: Integer;
    pMetaModel: IMsMetaModel;
    Ms: IMsModelSpace;
    DS: IRubricator;
    Attributes: IMetaAttributes;
    CDict, IDict: IMetabaseObjectDescriptor;
    Chain: IMsCalculationChainEntries;
    params: IMsModelParams;
    CParam, IParam: IMsModelParam;
    iterator: IMsCalculationChainMultiDimIterator;
    IteratorOpt: IMsDimIterateByDataOptions;
    IterStubs: IMsDimIterateByDataStubs;
    dimInstC, dimInstI: IDimInstance;
    IterDims: IMsDimIteratorDimensions;
    CIterDim, IIterDim: IMsDimIteratorDimension;
    Filter: IMsDimIteratorFilter;
    dimSelC, dimSelI: IDimSelection;
    IterStub: IMsDimIterateByDataStub;
    FilterDim: IMsDimIteratorFilteredDimension;
    model: IMsModel;
    Trans: IMsFormulaTransform;
    TransVar: IMsFormulaTransformVariable;
    slice: IMsFormulaTransformSlice;
    Selector: IMsFormulaTransformSelector;
    Formula: IMsFormula;
    Determ: IMsDeterministicTransform;
    TermInfo: IMsFormulaTermInfo;
    Expr: IExpression;
Begin
    // Get current repository
    mb := MetabaseClass.Active;
    // Get modelling container key
    MsKey := mb.GetObjectKeyById("MS");
    // Get the model
    pMetaModel := mb.ItemByIdNamespace("METAMODEL_MULTIDIMITERATOR", MsKey).edit As IMsMetaModel;
    // Get modeling container
    Ms := mb.Item(MsKey).Bind As IMsModelSpace;
    // Get time series database,
    // which is a data source for modeling container
    DS := Ms.Rubricator.Bind As IRubricator;
    // Get indicators attributes
    Attributes := DS.Facts.Attributes;
    // Get dictionaries used as a base for the CITY and INDICATOR attributes
    CDict := Attributes.FindById("CITY").ValuesObject;
    IDict := Attributes.FindById("INDICATOR").ValuesObject;
    // Get and clear metamodel calculation chain
    Chain := pMetaModel.CalculationChain;
    Chain.Clear;
    // Get and clear metamodel parameters
    params := pMetaModel.Params;
    params.Clear;
    // Add a parameter based on dictionary of the CITY attribute
    CParam := params.Add;
    CParam.DataType := DbDataType.integer;
    CParam.DefaultValue := 1;
    CParam.Hidden := True;
    CParam.Id := "CITY";
    CParam.Name := "City";
    CParam.LinkedObject := CDict;
    // Add a parameter based on dictionary of the INDICATOR attribute
    IParam := params.Add;
    IParam.DataType := DbDataType.Integer;
    IParam.DefaultValue := 1;
    IParam.Hidden := True;
    IParam.Id := "INDICATOR";
    IParam.Name := "Indicator";
    IParam.LinkedObject := IDict;
    // Add a multidimensional iterator to metamodel calculation chain
    iterator := Chain.AddMultiDimIterator("Multidimensional iterator");
    // Get iterator parameters by data
    IteratorOpt := Iterator.IterateByData;
    // Specify that it is active
    IteratorOpt.Active := True;
    // Set data source for iterator
    IterStubs := IteratorOpt.Stubs;
    IterStubs.Add(DS As IVariableStub);
    // Get iterated dimensions
    IterDims := Iterator.Dimensions;
    // Add a dimension based on dictionary of the CITY attribute
    dimInstC := CDict.Open(Null) As IDimInstance;
    CIterDim := IterDims.Add(dimInstC);
    // Specify that dimension is parametric
    CIterDim.Parameter := CParam;
    // Set data source for iterated dimension
    CIterDim.Stubs.Add(DS As IVariableStub);
    // Set filter of elements
    Filter := CIterDim.Filter;
    dimSelC := dimInstC.CreateSelection;
    dimSelC.SelectAll;
    Filter.Selection := dimSelC;
    // Add a dimension based on dictionary of the INDICATOR attribute
    dimInstI := IDict.Open(Null) As IDimInstance;
    IIterDim := IterDims.Add(dimInstI);
    // Specify that dimension is parametric
    IIterDim.Parameter := IParam;
    // Set data source for iterated dimension
    IIterDim.Stubs.Add(DS As IVariableStub);
    // Set filter of elements
    Filter := IIterDim.Filter;
    dimSelI := dimInstI.CreateSelection;
    dimSelI.SelectAll;
    Filter.Selection := dimSelI;
    // Get data source, using which iterations will be executed
    IterStub := IterStubs.Item(0);
    // Add a filtering by the dimension, on which the CITY attribute is based
    FilterDim := IterStub.Dimension(dimInstC.InstanceModel);
    Debug.WriteLine("  Filtering dimension: " + FilterDim.Dimension.Name);
    FilterDim.Filter.Selection := dimSelC;
    // Add a filtering by the dimension, on which the INDICATOR attribute is based
    FilterDim := IterStub.Dimension(dimInstI.InstanceModel);
    FilterDim.Filter.Selection := dimSelI;
    Debug.WriteLine("  Filtering dimension: " + FilterDim.Dimension.Name);
    // Create a model inside multidimensional iterator
    model := Iterator.Contents.AddExclusiveModel.Model;
    // Set up model
    Trans := model.Transform;
    // Add a modelling variable, which attributes are set by the parameters
    TransVar := Trans.Outputs.Add(DS As IVariableStub);
    Slice := TransVar.Slices.Add(Null);
    Slice.ParametrizedDimensions.Item(0).Parameter := IParam;
    Slice.ParametrizedDimensions.Item(1).Parameter := CParam;
    Selector := Trans.CreateSelector;
    Selector.Slice := Slice;
    // Set up model calculation method: determinate equation
    Formula := Trans.Transform(Selector);
    Formula.Kind := MsFormulaKind.Deterministic;
    Determ := Formula.Method As IMsDeterministicTransform;
    // Add an input variable, which attributes are set by the parameters
    TransVar := Trans.Inputs.Add(DS As IVariableStub);
    Slice := TransVar.Slices.Add(Null);
    Slice.ParametrizedDimensions.Item(0).Parameter := IParam;
    Slice.ParametrizedDimensions.Item(1).Parameter := CParam;
    TermInfo := Trans.CreateTermInfo;
    TermInfo.Slice := Slice;
    // Set expression to calculate a model
    Expr := Determ.Expression;
    Expr.AsString := TermInfo.TermInnerText + "+1";
    If Expr.ErrorInfo <> Null Then
        debug.WriteLine(Expr.ErrorInfo.ErrorMessage);
        Return;
    End If;
    // Save changes in the model
    model.MetabaseObject.Save;
    // Save changes of the metamodel
    (pMetaModel As IMetabaseObject).Save;
End Sub UserProc;