# Package net.corda.core.schemas

- Interface Summary
  Interface | Description
  --- | ---
  QueryableState | A contract state that may be mapped to database schemas configured for this node to support querying for, or filtering of, states.

- Class Summary
  Class | Description
  --- | ---
  MappedSchema | A database schema that might be configured for this node. As well as a name and version for identifying the schema, also list the classes that may be used in the generated object graph in order to configure the ORM tool.
  PersistentState | A super class for all mapped states exported to a schema that ensures the `class StateRef` appears on the database row. The `class StateRef` will be set to the correct value by the framework (there's no need to set during mapping generation by the state itself).
  PersistentStateRef | Embedded `class StateRef` representation used in state mapping.