fields property

The fields supported by this index.

For composite indexes, this requires a minimum of 2 and a maximum of 100 fields. The last field entry is always for the field path __name__. If, on creation, __name__ was not specified as the last field, it will be added automatically with the same direction as that of the last field defined. If the final field in a composite index is not directional, the __name__ will be ordered ASCENDING (unless explicitly specified). For single field indexes, this will always be exactly one entry with a field path equal to the field path of the associated field.