/// <summary> Gets a scalar value, calculated with the aggregate and expression specified. the field index specified is the field the expression and aggregate are applied on.</summary>
/// <param name="fieldIndex">Field index of field to which to apply the aggregate function and expression</param>
/// <param name="expressionToExecute">The expression to execute. Can be null</param>
/// <param name="aggregateToApply">Aggregate function to apply. </param>
/// <param name="filter">The filter to apply to retrieve the scalar</param>
/// <param name="relations">The relations to walk</param>
/// <param name="groupByClause">The groupby clause to apply to retrieve the scalar</param>
/// <returns>the scalar value requested</returns>
public virtual object GetScalar(ConditionFieldIndex fieldIndex, IExpression expressionToExecute, AggregateFunction aggregateToApply, IPredicate filter, IRelationCollection relations, IGroupByCollection groupByClause)
{
EntityFields fields = new EntityFields(1);
fields[0] = EntityFieldFactory.Create(fieldIndex);
if ((fields[0].ExpressionToApply == null) || (expressionToExecute != null))
{
fields[0].ExpressionToApply = expressionToExecute;
}
if ((fields[0].AggregateFunctionToApply == AggregateFunction.None) || (aggregateToApply != AggregateFunction.None))
{
fields[0].AggregateFunctionToApply = aggregateToApply;
}
ConditionDAO dao = DAOFactory.CreateConditionDAO();
return(dao.GetScalar(fields, base.Transaction, filter, relations, groupByClause));
}