private void reduceCasts(RexCall outerCast) {
RexNode[] operands = outerCast.getOperands();
if (operands.length != 1) {
return;
}
RelDataType outerCastType = outerCast.getType();
RelDataType operandType = operands[0].getType();
if (operandType.equals(outerCastType)) {
removableCasts.add(outerCast);
return;
}
// See if the reduction
// CAST((CAST x AS type) AS type NOT NULL)
// -> CAST(x AS type NOT NULL)
// applies. TODO jvs 15-Dec-2008: consider
// similar cases for precision changes.
if (!(operands[0] instanceof RexCall)) {
return;
}
RexCall innerCast = (RexCall) operands[0];
if (innerCast.getOperator() != SqlStdOperatorTable.castFunc) {
return;
}
if (innerCast.getOperands().length != 1) {
return;
}
RelDataTypeFactory typeFactory = preparingStmt.getFarragoTypeFactory();
RelDataType outerTypeNullable = typeFactory.createTypeWithNullability(outerCastType, true);
RelDataType innerTypeNullable = typeFactory.createTypeWithNullability(operandType, true);
if (outerTypeNullable != innerTypeNullable) {
return;
}
if (operandType.isNullable()) {
removableCasts.add(innerCast);
}
}
public static RelDataType createTypeFromProjection(
RelDataType type,
List<String> columnNameList,
RelDataTypeFactory typeFactory,
boolean caseSensitive) {
// If the names in columnNameList and type have case-sensitive differences,
// the resulting type will use those from type. These are presumably more
// canonical.
final List<RelDataTypeField> fields = new ArrayList<RelDataTypeField>(columnNameList.size());
for (String name : columnNameList) {
RelDataTypeField field = type.getField(name, caseSensitive);
fields.add(type.getFieldList().get(field.getIndex()));
}
return typeFactory.createStructType(fields);
}
/**
* Creates a record type with specified field names.
*
* <p>The array of field names may be null, or any of the names within it can be null. We
* recommend using explicit names where possible, because it makes it much easier to figure out
* the intent of fields when looking at planner output.
*
* @param typeFactory Type factory
* @param exprs Expressions
* @param names Field names, may be null, or elements may be null
* @return Record type
*/
public static RelDataType createStructType(
RelDataTypeFactory typeFactory, final RexNode[] exprs, final String[] names) {
return typeFactory.createStructType(
new RelDataTypeFactory.FieldInfo() {
public int getFieldCount() {
return exprs.length;
}
public String getFieldName(int index) {
if (names == null) {
return "$f" + index;
}
final String name = names[index];
if (name == null) {
return "$f" + index;
}
return name;
}
public RelDataType getFieldType(int index) {
return exprs[index].getType();
}
});
}
