public Double getPercentageOriginalRows(AggregateRelBase rel) {
// REVIEW jvs 28-Mar-2006: The assumption here seems to be that
// aggregation does not apply any filtering, so it does not modify the
// percentage. That's very much oversimplified.
return RelMetadataQuery.getPercentageOriginalRows(rel.getChild());
}
public Boolean areColumnsUnique(AggregateRelBase rel, BitSet columns, boolean ignoreNulls) {
// group by keys form a unique key
if (rel.getGroupCount() > 0) {
BitSet groupKey = new BitSet();
for (int i = 0; i < rel.getGroupCount(); i++) {
groupKey.set(i);
}
return BitSets.contains(columns, groupKey);
} else {
// interpret an empty set as asking whether the aggregation is full
// table (in which case it returns at most one row);
// TODO jvs 1-Sept-2008: apply this convention consistently
// to other relational expressions, as well as to
// RelMetadataQuery.getUniqueKeys
return columns.isEmpty();
}
}
