/**
* Looks up a field with a given name, returning null if not found.
*
* @param rowType Row type
* @param columnName Field name
* @return Field, or null if not found
*/
public static RelDataTypeField lookupField(
boolean caseSensitive, final RelDataType rowType, String columnName) {
RelDataTypeField field = rowType.getField(columnName, caseSensitive);
if (field != null) {
return field;
}
// If record type is flagged as having "any field you ask for",
// return a type. (TODO: Better way to mark accommodating types.)
RelDataTypeField extra = RelDataTypeImpl.extra(rowType);
if (extra != null) {
return new RelDataTypeFieldImpl(columnName, -1, extra.getType());
}
return null;
}
/**
* Creates an inference rule which returns a type with precision but no scale, such as {@code
* VARCHAR(100)}.
*/
public static ExplicitReturnTypeInference explicit(SqlTypeName typeName, int precision) {
return explicit(RelDataTypeImpl.proto(typeName, precision, false));
}
/** Creates an inference rule which returns a copy of a given data type. */
public static ExplicitReturnTypeInference explicit(RelDataType type) {
return explicit(RelDataTypeImpl.proto(type));
}