Answer: Catalog

The Unity Catalog organizes data in a hierarchical model starting from the metastore down to tables. The catalog serves as the first layer in this hierarchy, enabling the organization of data assets. Following the catalog, schemas (or databases) come next, containing tables and views. Tables represent the lowest level, which can be either external or managed, with views providing read-only access to these tables. The three-level namespace notation (`<catalog_name>.<schema_name>.<table_name>`) is used to reference data within this structure.

Author: LeetQuiz Editorial Team