protected void FormatMeasure(MeasureExpression m)
{
if (m.Filter != null)
{
this.Builder.Append("\"" + m.Name.TrimStart('[').TrimEnd(']') + "\"" + "," + "CALCULATE(" +
m.DbName +
",");
this.Visit(m.Filter);
this.Builder.Append(")");
}
else if (m is LookupExpression)
{
this.Builder.Append("\"" + m.Name.TrimStart('[').TrimEnd(']') + "\"" + "," + m.DbName);
}
else if (m is XAggregationExpression)
{
this.Visit(m as XAggregationExpression);
}
else if (m.DbName != null)
{
this.Builder.Append("\"" + m.Name.TrimStart('[').TrimEnd(']') + "\"" + "," + "CALCULATE(" +
m.DbName +
")");
}
else
{
this.Builder.Append(m.Name);
}
}
/// <summary>
/// creates method call to get value from measure columns
/// </summary>
/// <param name="measure">measure expression</param>
/// <returns>get value method call expression</returns>
protected override Expression VisitMeasure(MeasureExpression measure)
{
string measureProjectionName = MeasureNameReference(measure.Name);
var measureExpressions =
new Expression[]
{
Expression.Constant(measureProjectionName),
Expression.Constant(measure.Type)
};
return(Expression.Convert(Expression.Call(_row, _getValue, measureExpressions), measure.Type));
}
private void BuildMeasure(MeasureExpression m)
{
if (string.IsNullOrEmpty(m.TableName))
{
FormatMeasure(m);
}
else
{
this.Builder.Append("\"" + m.Name.TrimStart('[').TrimEnd(']') + "\"" + ",");
this.Builder.Append(m.TableName + m.Name);
}
}
/// <summary>
/// Visitor function for column projection
/// </summary>
/// <param name="expression">expression to be visited</param>
/// <returns>the expression</returns>
public override Expression Visit(Expression expression)
{
if (_candidates.Contains(expression))
{
var measureExpression = expression as MeasureExpression;
if (measureExpression != null)
{
MeasureExpression m = measureExpression;
ColumnExpression mappedMeasure;
if (_map.TryGetValue(m, out mappedMeasure))
{
return(mappedMeasure);
}
_columns.Add(new MeasureDeclaration(m.Name, m.Name, m));
// The mapped measure can only be used as backreference to something known
mappedMeasure = new MeasureExpression(m.Type, m.Name, null, m.Name, null);
_map[m] = mappedMeasure;
return(mappedMeasure);
}
var column = expression as ColumnExpression;
if (column == null)
{
return(base.Visit(expression));
}
ColumnExpression mapped;
if (_map.TryGetValue(column, out mapped))
{
return(mapped);
}
_columns.Add(new ColumnDeclaration(column.Name, column.Name, column));
mapped = new ColumnExpression(column.Type, column.Name, column.DbName, column.TableName);
_map[column] = mapped;
return(mapped);
}
return(base.Visit(expression));
}
/// <summary>
/// Format Measure column
/// </summary>
/// <param name="column">the measure column expression</param>
/// <returns>the original expression</returns>
protected Expression VisitMeasureColumn(MeasureExpression column)
{
this.Builder.Append(column.Name);
return(column);
}
protected override Expression VisitMeasure(MeasureExpression measure)
{
return(VisitColumn(measure));
}
