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()));
}
public override ITable Evaluate(IQueryContext context)
{
ITable t = Child.Evaluate(context);
Expression exp = expression;
// Assert that all variables in the expression are identical.
IEnumerable <ObjectName> allVars = exp.AllVariables();
ObjectName v = null;
foreach (ObjectName cv in allVars)
{
if (v != null && !cv.Equals(v))
{
throw new ApplicationException("Assertion failed: Range plan does not contain common variable.");
}
v = cv;
}
// Find the variable field in the table.
int col = ((Table)t).FindFieldName(v);
if (col == -1)
{
throw new ApplicationException("Couldn't find column reference in table: " + v);
}
DataColumnInfo field = t.TableInfo[col];
// Calculate the range
SelectableRangeSet range = new SelectableRangeSet();
CalcRange(context, field, range, exp);
// Select the range from the table
SelectableRange[] ranges = range.ToArray();
return(t.RangeSelect(v, ranges));
}