Density

The density configuration for the index.

Enums
DENSITY_UNSPECIFIED Unspecified. It will use database default setting. This value is input only.
SPARSE_ALL

In order for an index entry to be added, the document must contain all fields specified in the index.

This is the only allowed value for indexes having ApiScope ANY_API and DATASTORE_MODE_API.

SPARSE_ANY In order for an index entry to be added, the document must contain at least one of the fields specified in the index. Non-existent fields are treated as having a NULL value when generating index entries.
DENSE An index entry will be added regardless of whether the document contains any of the fields specified in the index. Non-existent fields are treated as having a NULL value when generating index entries.