ISQLComponents.Where

Syntax

Where: String;

Description

The Where property determines a part of query where the whole condition of element selection for dimensions is specified.

Comments

If the property value was obtained in a separate variable and the expression is modified in the variable, then it is required to rewrite property value to apply changes:

Public Class SQLCallback: Object, ISQLCallback
    Sub BeforeConstruction(Components: ISQLComponents);
    Var
        Where: String;
    Begin
        Where := Components.Where;
        //...
        //Modification of Where
        //...
        Components.Where := Where;
    End Sub BeforeConstruction;

    Sub AfterConstruction(Var SQL: String);
    Begin
    End Sub AfterConstruction;
End Class SQLCallback;

A particular parts where conditions to select elements of a specific dimension are specified, can be obtained using the ISQLComponents.Condition property.

Example

The specified class is a handler of query generation for cube data extraction. The class should be saved to the unit and assign it as a handler to cube data source using the IStandardCubeDataset.SetCallback.

Public Class SQLCallback: Object, ISQLCallback
    Sub BeforeConstruction(Components: ISQLComponents);
    Var
        i: Integer;
        Condition: ISQLCondition;
    Begin
        Debug.WriteLine("Where: " + Components.Where); Components.Where := Components.Where;
        Debug.WriteLine("ConditionCount: " + Components.ConditionCount.ToString);
        For i := 0 To Components.ConditionCount - 1 Do
            Condition := Components.Condition(i);
            Debug.WriteLine("Condition " + Condition.Condition);
            Debug.Indent;
            Debug.WriteLine("Fields: " + Condition.Fields);
            Debug.WriteLine("TempTable: " + Condition.TempTable);
            Debug.WriteLine("TempTableAlias: " + Condition.TempTableAlias);
            Debug.WriteLine("TempTableAttrLinkedFields: " + Condition.TempTableAttrLinkedFields);
            Debug.WriteLine("TempTableFields: " + Condition.TempTableFields);
            Debug.WriteLine("TempTableHasNulls: " + Condition.TempTableHasNulls.ToString);
            Debug.WriteLine("TempTableRecCount: " + Condition.TempTableRecCount.ToString);
            Debug.Unindent;
        End For;
        Debug.WriteLine("TableAlias: " + Components.TableAlias);
    End Sub BeforeConstruction;

    Sub AfterConstruction(Var SQL: String);
    Begin
    End Sub AfterConstruction;
End Class SQLCallback;

On executing the BeforeConstruction procedure, all parts of generated query will be displayed to development environment console. If required, any block can be uncommented and a part of query can be modified. Fully generated query will be displayed on executing the AfterConstruction method.

See also:

ISQLComponents