/**
* Creates a relational expression which projects an array of expressions, and optionally
* optimizes.
*
* <p>The result may not be a {@link ProjectRel}. If the projection is trivial, <code>child</code>
* is returned directly; and future versions may return other formulations of expressions, such as
* {@link CalcRel}.
*
* @param child input relational expression
* @param exprs list of expressions for the input columns
* @param fieldNames aliases of the expressions, or null to generate
* @param optimize Whether to return <code>child</code> unchanged if the projections are trivial.
*/
public static RelNode createProject(
RelNode child, List<RexNode> exprs, List<String> fieldNames, boolean optimize) {
final RelOptCluster cluster = child.getCluster();
final RexProgram program =
RexProgram.create(child.getRowType(), exprs, null, fieldNames, cluster.getRexBuilder());
final List<RelCollation> collationList = program.getCollations(child.getCollationList());
if (DeprecateProjectAndFilter) {
return new CalcRel(
cluster, child.getTraitSet(), child, program.getOutputRowType(), program, collationList);
} else {
final RelDataType rowType =
RexUtil.createStructType(cluster.getTypeFactory(), exprs, fieldNames);
if (optimize && RemoveTrivialProjectRule.isIdentity(exprs, rowType, child.getRowType())) {
return child;
}
return new ProjectRel(
cluster,
cluster.traitSetOf(
collationList.isEmpty() ? RelCollationImpl.EMPTY : collationList.get(0)),
child,
exprs,
rowType,
ProjectRelBase.Flags.Boxed);
}
}
/**
* Creates a relational expression which projects an array of expressions, and optionally
* optimizes.
*
* <p>The result may not be a {@link ProjectRel}. If the projection is trivial, <code>child</code>
* is returned directly; and future versions may return other formulations of expressions, such as
* {@link CalcRel}.
*
* @param child input relational expression
* @param exprs list of expressions for the input columns
* @param fieldNames aliases of the expressions, or null to generate
* @param optimize Whether to return <code>child</code> unchanged if the projections are trivial.
*/
public static RelNode createProject(
RelNode child, List<RexNode> exprs, List<String> fieldNames, boolean optimize) {
final RelOptCluster cluster = child.getCluster();
final RexProgram program =
RexProgram.create(child.getRowType(), exprs, null, fieldNames, cluster.getRexBuilder());
final List<RelCollation> collationList = program.getCollations(child.getCollationList());
if (DEPRECATE_PROJECT_AND_FILTER) {
return new CalcRel(
cluster, child.getTraitSet(), child, program.getOutputRowType(), program, collationList);
} else {
final RelDataType rowType =
RexUtil.createStructType(
cluster.getTypeFactory(),
exprs,
fieldNames == null
? null
: SqlValidatorUtil.uniquify(fieldNames, SqlValidatorUtil.F_SUGGESTER));
if (optimize && RemoveTrivialProjectRule.isIdentity(exprs, rowType, child.getRowType())) {
return child;
}
return new ProjectRel(
cluster,
cluster.traitSetOf(
collationList.isEmpty() ? RelCollationImpl.EMPTY : collationList.get(0)),
child,
exprs,
rowType,
ProjectRelBase.Flags.BOXED);
}
}