/**
* Derives the list of column names suitable for NATURAL JOIN. These are the columns that occur
* exactly once on each side of the join.
*
* @param leftRowType Row type of left input to the join
* @param rightRowType Row type of right input to the join
* @return List of columns that occur once on each side
*/
public static List<String> deriveNaturalJoinColumnList(
RelDataType leftRowType, RelDataType rightRowType) {
final List<String> naturalColumnNames = new ArrayList<>();
final List<String> leftNames = leftRowType.getFieldNames();
final List<String> rightNames = rightRowType.getFieldNames();
for (String name : leftNames) {
if ((Collections.frequency(leftNames, name) == 1)
&& (Collections.frequency(rightNames, name) == 1)) {
naturalColumnNames.add(name);
}
}
return naturalColumnNames;
}
/**
* Creates a relational expression that projects the given fields of the input.
*
* <p>Optimizes if the fields are the identity projection.
*
* @param relBuilder RelBuilder
* @param child Input relational expression
* @param posList Source of each projected field
* @return Relational expression that projects given fields
*/
public static RelNode createProject(
final RelBuilder relBuilder, final RelNode child, final List<Integer> posList) {
RelDataType rowType = child.getRowType();
final List<String> fieldNames = rowType.getFieldNames();
final RexBuilder rexBuilder = child.getCluster().getRexBuilder();
return createProject(
child,
new AbstractList<RexNode>() {
public int size() {
return posList.size();
}
public RexNode get(int index) {
final int pos = posList.get(index);
return rexBuilder.makeInputRef(child, pos);
}
},
new AbstractList<String>() {
public int size() {
return posList.size();
}
public String get(int index) {
final int pos = posList.get(index);
return fieldNames.get(pos);
}
},
true,
relBuilder);
}
protected DrillRel addRenamedProject(DrillRel rel, RelDataType validatedRowType) {
RelDataType t = rel.getRowType();
RexBuilder b = rel.getCluster().getRexBuilder();
List<RexNode> projections = Lists.newArrayList();
int projectCount = t.getFieldList().size();
for (int i = 0; i < projectCount; i++) {
projections.add(b.makeInputRef(rel, i));
}
final List<String> fieldNames2 =
SqlValidatorUtil.uniquify(validatedRowType.getFieldNames(), SqlValidatorUtil.F_SUGGESTER2);
RelDataType newRowType =
RexUtil.createStructType(rel.getCluster().getTypeFactory(), projections, fieldNames2);
DrillProjectRel topProj =
DrillProjectRel.create(rel.getCluster(), rel.getTraitSet(), rel, projections, newRowType);
// Add a final non-trivial Project to get the validatedRowType, if child is not project.
if (rel instanceof Project && DrillRelOptUtil.isTrivialProject(topProj, true)) {
return rel;
} else {
return topProj;
}
}
public RelDataType toSql(RelDataType type) {
if (type instanceof RelRecordType) {
return createStructType(
Lists.transform(
type.getFieldList(),
new Function<RelDataTypeField, RelDataType>() {
public RelDataType apply(RelDataTypeField a0) {
return toSql(a0.getType());
}
}),
type.getFieldNames());
}
if (type instanceof JavaType) {
return createTypeWithNullability(createSqlType(type.getSqlTypeName()), type.isNullable());
}
return type;
}
private SyntheticRecordType(RelDataType relType, String name) {
this.relType = relType;
this.name = name;
assert relType == null || Util.isDistinct(relType.getFieldNames())
: "field names not distinct: " + relType;
}
