/**
* Resolves a multi-part identifier such as "SCHEMA.EMP.EMPNO" to a namespace. The returned
* namespace may represent a schema, table, column, etc.
*
* @pre names.size() > 0
* @post return != null
*/
public static SqlValidatorNamespace lookup(SqlValidatorScope scope, List<String> names) {
Util.pre(names.size() > 0, "names.size() > 0");
SqlValidatorNamespace namespace = null;
for (int i = 0; i < names.size(); i++) {
String name = names.get(i);
if (i == 0) {
namespace = scope.resolve(name, null, null);
} else {
namespace = namespace.lookupChild(name);
}
}
Util.permAssert(namespace != null, "post: namespace != null");
return namespace;
}
public RelNode convertSqlToRel(String sql) {
Util.pre(sql != null, "sql != null");
final SqlNode sqlQuery;
try {
sqlQuery = parseQuery(sql);
} catch (Exception e) {
throw Util.newInternal(e); // todo: better handling
}
final RelDataTypeFactory typeFactory = getTypeFactory();
final Prepare.CatalogReader catalogReader = createCatalogReader(typeFactory);
final SqlValidator validator = createValidator(catalogReader, typeFactory);
final SqlToRelConverter converter =
createSqlToRelConverter(validator, catalogReader, typeFactory);
converter.setTrimUnusedFields(true);
final SqlNode validatedQuery = validator.validate(sqlQuery);
final RelNode rel = converter.convertQuery(validatedQuery, false, true);
Util.post(rel != null, "return != null");
return rel;
}