Using the SAS Metadata Model

Understanding Metadata Types

A metadata type is a template that models the metadata for an application element. For example, the RepositoryBase metadata type models the information kept about a repository, the Person metadata type models the information kept about a Person, and the Column metadata type models the information kept about a SAS table column.

SAS provides metadata types in two namespaces: SAS and REPOS. The SAS namespace, which describes application elements, defines approximately 160 metadata types. The REPOS namespace defines only two metadata types.

The Metadata Type Template

Every metadata type in the SAS Metadata Model is defined by two sets of properties:

Attributes describe the characteristics of the metadata type. Id, Name, and Description are examples of attributes that are defined for all metadata types.
Associations describe the metadata type's relationships with other metadata types. AccessControls, ResponsibleParties, and Changes are examples of associations that are defined for most metadata types.

Note: Throughout SAS Open Metadata Architecture documentation, the term "property" refers to both a metadata type's attributes and associations.

The SAS Metadata Model is a hierarchical model. Therefore, every metadata type has a set of inherited and unique properties.

The Type Hierarchy

In the REPOS namespace, the RepositoryBase metadata type inherits properties from the Repository metadata type.

The SAS namespace metadata types inherit properties from a Root metadata type. They also inherit properties from either the PrimaryType or SecondaryType metadata type, and one or more functional abstract types.

An abstract metadata type is a supertype that defines shared properties that are extended by other metadata types. The extended types are subtypes of the abstract type. An abstract metadata type can be specified in queries to list instances of its subtypes when appropriate flags are set in metadata methods. But, the abstract type is never itself instantiated in a SAS Metadata Repository. Instead, abstract metadata types define properties for the basic management of their subtypes. The Repository, Root, PrimaryType, and SecondaryType metadata types are abstract metadata types.

For more information about the PrimaryType and SecondaryType metadata types, see Understanding the PrimaryType and SecondaryType Abstract Types.

For a textual representation of the type hierarchy, see Hierarchical Listing of SAS Namespace Types. The metadata types on the left side of the page are the functional abstract objects. Notice how the SAS Metadata Model uses subtyping to extend the functionality of object classes. Many of the subtypes have subtypes of their own.

Using the Metadata Types

The SAS namespace metadata types represent the basic components that define all SAS application entities. The metadata types describe the components at a very basic level. The metadata types are intended to be used in combination to describe the application data and entities used by an application. The metadata types are combined by defining associations between them. Combining metadata types that describe an entity creates a logical metadata definition. In this documentation, the phrase "logical metadata definition" refers to the collection of SAS Metadata Model metadata types and associations that describe an entity in an application.

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