public static IEnumerable <long> SelectRows(this ITable table, int column, Operator op, DataObject cell)
{
// If the cell is of an incompatible type, return no results,
DataType colType = table.TableInfo[column].DataType;
if (!cell.DataType.IsComparable(colType))
{
// Types not comparable, so return 0
return(new List <long>(0));
}
// Get the selectable scheme for this column
SelectableScheme ss = table.GetScheme(column);
// If the operator is a standard operator, use the interned SelectableScheme
// methods.
if (op.IsEquivalent(Operator.Equal))
{
return(ss.SelectEqual(cell));
}
if (op.IsEquivalent(Operator.NotEqual))
{
return(ss.SelectNotEqual(cell));
}
if (op.IsEquivalent(Operator.Greater))
{
return(ss.SelectGreater(cell));
}
if (op.IsEquivalent(Operator.Smaller))
{
return(ss.SelectLess(cell));
}
if (op.IsEquivalent(Operator.GreaterOrEqual))
{
return(ss.SelectGreaterOrEqual(cell));
}
if (op.IsEquivalent(Operator.SmallerOrEqual))
{
return(ss.SelectLessOrEqual(cell));
}
// If it's not a standard operator (such as IS, NOT IS, etc) we generate the
// range set especially.
SelectableRangeSet rangeSet = new SelectableRangeSet();
rangeSet.Intersect(op, cell);
return(ss.SelectRange(rangeSet.ToArray()));
}
/// <summary>
/// Updates a range with the given expression.
/// </summary>
/// <param name="context"></param>
/// <param name="range"></param>
/// <param name="field"></param>
/// <param name="e"></param>
private static void UpdateRange(IQueryContext context, SelectableRangeSet range, DataColumnInfo field, Expression e)
{
var binary = (BinaryExpression)e;
Operator op = binary.Operator;
Expression[] exps = { binary.Left, binary.Right };
// Evaluate to an object
DataObject cell = exps[1].Evaluate(context);
// If the evaluated object is not of a comparable type, then it becomes
// null.
DataType fieldType = field.DataType;
if (!cell.DataType.IsComparable(fieldType))
{
cell = new DataObject(fieldType, null);
}
// Intersect this in the range set
range.Intersect(op, cell);
}