IModelling.Nvl

Syntax

Nvl(Input: Variant; Value: Double): Variant;

Parameters

Input. Variable that requires missing data substitution.

Value. Vale to substitute missing data.

Description

The Nvl method substitutes missing data of variable with the specified value.

Comments

The Value parameter cannot take the Null value.

Example

Executing the example requires that the repository contains a modeling container with the MS identifier. This container includes a model with the MODEL_D identifier that is calculated by the determinate equation method and contains at least one input variable.

Add links to the Metabase and Ms system assemblies.

Sub UserNvl;
Var
    Mb: IMetabase;
    ModelSpace, ModelObj: IMetabaseObject;
    Transf: IMsFormulaTransform;
    Formula: IMsFormula;
    Model: IMsModel;
    Determ: IMsDeterministicTransform;
    TransVar: IMsFormulaTransformVariable;
    Slice: IMsFormulaTransformSlice;
    TermInfo: IMsFormulaTermInfo;
    Expr: IExpression;
Begin
    // Get repository
    Mb := MetabaseClass.Active;
    // Get modeling container
    ModelSpace := Mb.ItemById("MS").Bind;
    // Get the model
    ModelObj := Mb.ItemByIdNamespace("MODEL_D", ModelSpace.Key).Edit;
    Model := ModelObj As IMsModel;
    // Get model calculation parameters
    Transf := Model.Transform;
    Formula := Transf.FormulaItem(0);
    Determ := Formula.Method As IMsDeterministicTransform;
    // Get the first input variable
    TransVar := Transf.Inputs.Item(0);
    Slice := TransVar.Slices.Item(0);
    TermInfo := Transf.CreateTermInfo;
    TermInfo.Slice := Slice;
    // Set mode of passing variable into calculation
    TermInfo.Type := MsFormulaTermType.Pointwise;
    // Get model calculation expression
    Expr := Determ.Expression;
    Expr.References := "Ms";
    // Set model calculation expression
    Expr.AsString := "Nvl(" + TermInfo.TermInnerText + ", 5)";
    // Check if the expression is correct
    If Expr.Valid
        // If the expression is set correctly, save the model
        Then ModelObj.Save;
        // If the expression is incorrect, display a message to the console window
        Else Debug.WriteLine("Model is not saved: error in the formula");
    End If;
End Sub UserNvl;

After executing the example a new expression will be set for the determinate equation model: after model calculation empty values in the first input variable are will be substituted with the 5 value.

Example of Use in Expressions

Expression 1:

nvl({Population|Anchorage[t]}, 4)

Result: missing data in the Population|Anchorage time series is substituted with the 4 value.

Use: it can be used in formulas of cross functional expression editor in any platform tool where it is available.

Expression 2:

nvl(X1, 3)

Result: missing data in the X1 factor is substituted with the 3 value.

Use: it can be used in model formulas of modeling container.