Entities
This page documents various entities that can be managed in Apache Polaris (Incubating).
Catalog
A catalog is a top-level entity in Polaris that may contain other entities like namespaces and tables. These map directly to Apache Iceberg catalogs.
For information on managing catalogs with the REST API or for more information on what data can be associated with a catalog, see the API docs.
Storage Type
All catalogs in Polaris are associated with a storage type. Valid Storage Types are S3, Azure, and GCS. The FILE type is also additionally available for testing. Each of these types relates to a different storage provider where data within the catalog may reside. Depending on the storage type, various other configurations may be set for a catalog including credentials to be used when accessing data inside the catalog.
For details on how to use Storage Types in the REST API, see the API docs.
Namespace
A namespace is a logical entity that resides within a catalog and can contain other entities such as tables or views. Some other systems may refer to namespaces as schemas or databases.
In Polaris, namespaces can be nested. For example, a.b.c.d.e.f.g is a valid namespace. b is said to reside within a, and so on.
For information on managing namespaces with the REST API or for more information on what data can be associated with a namespace, see the API docs.
Table
Polaris tables are entities that map to Apache Iceberg tables.
For information on managing tables with the REST API or for more information on what data can be associated with a table, see the API docs.
View
Polaris views are entities that map to Apache Iceberg views.
For information on managing views with the REST API or for more information on what data can be associated with a view, see the API docs.
Principal
Polaris principals are unique identities that can be used to represent users or services. Each principal may have one or more principal roles assigned to it for the purpose of accessing catalogs and the entities within them.
For information on managing principals with the REST API or for more information on what data can be associated with a principal, see the API docs.
Principal Role
Polaris principal roles are labels that may be granted to principals. Each principal may have one or more principal roles, and the same principal role may be granted to multiple principals. Principal roles may be assigned based on the persona or responsibilities of a given principal, or on how that principal will need to access different entities within Polaris.
For information on managing principal roles with the REST API or for more information on what data can be associated with a principal role, see the API docs.
Catalog Role
Polaris catalog roles are labels that may be granted to catalogs. Each catalog may have one or more catalog roles, and the same catalog role may be granted to multiple catalogs. Catalog roles may be assigned based on the nature of data that will reside in a catalog, or by the groups of users and services that might need to access that data.
Each catalog role may have multiple privileges granted to it, and each catalog role can be granted to one or more principal roles. This is the mechanism by which principals are granted access to entities inside a catalog such as namespaces and tables.
Privilege
Polaris privileges are granted to catalog roles in order to grant principals with a given principal role some degree of access to catalogs with a given catalog role. When a privilege is granted to a catalog role, any principal roles granted that catalog role receive the privilege. In turn, any principals who are granted that principal role receive it.
A privilege can be scoped to any entity inside a catalog, including the catalog itself.
For a list of supported privileges for each privilege class, see the API docs: