Managing Column Families

JSON tables store data in column families, which are collections of fields that are stored together on disk.

Each table has a default column family, which is default storage for all fields in the documents of a table. You can create additional column families to store data for a collection of fields in a separate location on disk. Queries that operate only on data that is stored in a column family are more efficient and better performing than queries on the same data when that data is stored with other data in a table. You can also cache values from a column family in memory.

Applications do not need to be aware of the existence of column families. They perform CRUD operations by using the paths of fields in a document. For example, to update any of the fields below a.c, an application does not need to be aware that the field is in the column family at the path a.c. The application simply moves through the document along the path to the field.

For more information, see Column Families in JSON Tables.