RelProtoDataType getRelDataType(
DatabaseMetaData metaData, String catalogName, String schemaName, String tableName)
throws SQLException {
final ResultSet resultSet = metaData.getColumns(catalogName, schemaName, tableName, null);
// Temporary type factory, just for the duration of this method. Allowable
// because we're creating a proto-type, not a type; before being used, the
// proto-type will be copied into a real type factory.
final RelDataTypeFactory typeFactory = new SqlTypeFactoryImpl();
final RelDataTypeFactory.FieldInfoBuilder fieldInfo = typeFactory.builder();
while (resultSet.next()) {
final String columnName = resultSet.getString(4);
final int dataType = resultSet.getInt(5);
final String typeString = resultSet.getString(6);
final int size = resultSet.getInt(7);
final int scale = resultSet.getInt(9);
RelDataType sqlType = sqlType(typeFactory, dataType, size, scale, typeString);
boolean nullable = resultSet.getBoolean(11);
fieldInfo.add(columnName, sqlType).nullable(nullable);
}
resultSet.close();
return RelDataTypeImpl.proto(fieldInfo.build());
}
private static RelDataType makeStruct(RelDataTypeFactory typeFactory, RelDataType type) {
if (type.isStruct()) {
return type;
}
return typeFactory.createStructType(RelDataTypeFactory.FieldInfoBuilder.of("$0", type));
}