Google Cloud Platform for Developers

Entities, kinds, and properties

The fundamental component in Datastore is the entity. Each entity constitutes a discrete object in the database, and every entity is of a specific kind, or category of entities. The relational database equivalent of this would be tables for kinds, and table rows for entities.

In addition to kind, each entity is composed of one or more properties, which roughly correlate to columns or fields in a relational database table. Whereas relational databases rely on well-defined schemata to guarantee uniformity of data within a table, Datastore does not impose any uniformity on the properties of a given entity. This means that two entities of the same kind could have entirely different sets of properties.

The lack ...