Database Reference
In-Depth Information
Chapter 8. Managing the Metadata
Services Repository and Dehydration
Store
Oracle Metadata Services (MDS)
is a declarative metadata repository used with
Oracle SOA Suite 11g to store metadata of composites and web-based applic-
ations that are deployed to the service infrastructure. While a composite is be-
ing deployed, its associated metadata, including component configurations, web
service definitions, business rule dictionaries, and security policy definitions are
seeded first into the MDS repository and are then made available to the ser-
vice infrastructure at runtime. In this way the MDS framework facilitates dynam-
ic runtime configurations to be applied to already deployed composites to cater
to ad hoc customizations with ease and flexibility. A customized composite ap-
plication consists of an original metadata snapshot of the composite and a layer
containing all customizations. The MDS stores the customizations in a metadata
repository that are retrieved at runtime and merged with the base metadata to re-
veal the customized application. Having an MDS in place allows the Oracle SOA
Suite 11g infrastructure to enable runtime modifications to business rules, domain
value maps, human workflow, and certain aspects of business processes. As an
administrator it is of great use to know the basics of MDS, the underlying data-
base it resides on, activities involved in creating MDS partitions, migrating cus-
tomizations, and so on.
Another important and widely adopted development practice is the use of MDS as
a repository for all common components that are shared across multiple compos-
ites and applications. Reusable integration artifacts such as XML schemas de-
fining your canonical data model, WSDLs defining enterprise business services,
common fault policies, event definitions, and business rules can all be seeded
to the MDS as a
Metadata Archive (MAR)
—a compressed archive of selected
metadata, and can then be used and looked up from across multiple projects.
MDS assets can be maintained in either the database or in a file-based store.
For reasons of scalability, reliability, and usability, we recommend the use of a
