How to use

RelMdColumnUniqueness

in

org.apache.calcite.rel.metadata

public Boolean areColumnsUnique(Minus rel, RelMetadataQuery mq,
  ImmutableBitSet columns, boolean ignoreNulls) {
 if (areColumnsUnique((SetOp) rel, mq, columns, ignoreNulls)) {
  return true;
 }
 return mq.areColumnsUnique(rel.getInput(0), columns, ignoreNulls);
}

public Boolean areColumnsUnique(RelSubset rel, RelMetadataQuery mq,
  ImmutableBitSet columns, boolean ignoreNulls) {
 int nullCount = 0;
 for (RelNode rel2 : rel.getRels()) {
  if (rel2 instanceof Aggregate
    || rel2 instanceof Filter
    || rel2 instanceof Values
    || rel2 instanceof TableScan
    || simplyProjects(rel2, columns)) {
   try {
    final Boolean unique = mq.areColumnsUnique(rel2, columns, ignoreNulls);
    if (unique != null) {
     if (unique) {
      return true;
     }
    } else {
     ++nullCount;
    }
   } catch (CyclicMetadataException e) {
    // Ignore this relational expression; there will be non-cyclic ones
    // in this set.
   }
  }
 }
 return nullCount == 0 ? false : null;
}

case INNER:
 final Pair<ImmutableBitSet, ImmutableBitSet> leftAndRightColumns =
   splitLeftAndRightColumns(rel.getLeft().getRowType().getFieldCount(),
     columns);
 final ImmutableBitSet leftColumns = leftAndRightColumns.left;

public static final RelMetadataProvider SOURCE =
  ReflectiveRelMetadataProvider.reflectiveSource(
    BuiltInMethod.COLUMN_UNIQUENESS.method, new RelMdColumnUniqueness());

case INNER:
 final Pair<ImmutableBitSet, ImmutableBitSet> leftAndRightColumns =
   splitLeftAndRightColumns(rel.getLeft().getRowType().getFieldCount(),
     columns);
 final ImmutableBitSet leftColumns = leftAndRightColumns.left;

public static final RelMetadataProvider SOURCE =
  ReflectiveRelMetadataProvider.reflectiveSource(
    BuiltInMethod.COLUMN_UNIQUENESS.method, new RelMdColumnUniqueness());

public Boolean areColumnsUnique(Minus rel, RelMetadataQuery mq,
  ImmutableBitSet columns, boolean ignoreNulls) {
 if (areColumnsUnique((SetOp) rel, mq, columns, ignoreNulls)) {
  return true;
 }
 return mq.areColumnsUnique(rel.getInput(0), columns, ignoreNulls);
}

  splitLeftAndRightColumns(rel.getLeft().getRowType().getFieldCount(),
    columns);
final ImmutableBitSet leftColumns = leftAndRightColumns.left;

public Boolean areColumnsUnique(RelSubset rel, RelMetadataQuery mq,
  ImmutableBitSet columns, boolean ignoreNulls) {
 int nullCount = 0;
 for (RelNode rel2 : rel.getRels()) {
  if (rel2 instanceof Aggregate
    || rel2 instanceof Filter
    || rel2 instanceof Values
    || rel2 instanceof TableScan
    || simplyProjects(rel2, columns)) {
   try {
    final Boolean unique = mq.areColumnsUnique(rel2, columns, ignoreNulls);
    if (unique != null) {
     if (unique) {
      return true;
     }
    } else {
     ++nullCount;
    }
   } catch (CyclicMetadataException e) {
    // Ignore this relational expression; there will be non-cyclic ones
    // in this set.
   }
  }
 }
 return nullCount == 0 ? false : null;
}

public Boolean areColumnsUnique(Intersect rel, RelMetadataQuery mq,
  ImmutableBitSet columns, boolean ignoreNulls) {
 if (areColumnsUnique((SetOp) rel, mq, columns, ignoreNulls)) {
  return true;
 }
 for (RelNode input : rel.getInputs()) {
  Boolean b = mq.areColumnsUnique(input, columns, ignoreNulls);
  if (b != null && b) {
   return true;
  }
 }
 return false;
}

  splitLeftAndRightColumns(rel.getLeft().getRowType().getFieldCount(),
    columns);
final ImmutableBitSet leftColumns = leftAndRightColumns.left;

public Boolean areColumnsUnique(Intersect rel, RelMetadataQuery mq,
  ImmutableBitSet columns, boolean ignoreNulls) {
 if (areColumnsUnique((SetOp) rel, mq, columns, ignoreNulls)) {
  return true;
 }
 for (RelNode input : rel.getInputs()) {
  Boolean b = mq.areColumnsUnique(input, columns, ignoreNulls);
  if (b != null && b) {
   return true;
  }
 }
 return false;
}

    .get(BuiltInMethod.COLUMN_UNIQUENESS.method)
    .iterator().next();
assertThat(handler.areColumnsUnique(values, mq, col0, false),
  is(true));
assertThat(handler.areColumnsUnique(values, mq, col1, false),
  is(false));
assertThat(handler.areColumnsUnique(values, mq, colAll, false),
  is(true));
assertThat(handler.areColumnsUnique(values, mq, colNone, false),
  is(false));

    .get(BuiltInMethod.COLUMN_UNIQUENESS.method)
    .iterator().next();
assertThat(handler.areColumnsUnique(values, mq, col0, false),
  is(true));
assertThat(handler.areColumnsUnique(values, mq, col1, false),
  is(false));
assertThat(handler.areColumnsUnique(values, mq, colAll, false),
  is(true));
assertThat(handler.areColumnsUnique(values, mq, colNone, false),
  is(false));