A centralized architecture consists of a single Metadata repository that contains copies of Metadata from the various sources. Organizations with limited IT resources or those seeking to automate as much as possible, may choose to avoid this architecture option. Organizations seeking a high degree of consistency within the common Metadata repository can benefit from a centralized architecture.

Advantages of a centralized repository include:

• High availability, since it is independent of the source systems
• Quick Metadata retrieval, since the repository and the query reside together
• Resolved database structures not affected by the proprietary nature of third party or commercial systems
• Extracted Metadata may be transformed, customized, or enhanced with additional Metadata that may not reside in the source system, improving quality

Some limitations of the centralized approach include:

• Complex processes are necessary to ensure that changes in source Metadata are quickly replicated into the repository
• Maintenance of a centralized repository can be costly
• Extraction could require custom modules or middleware
• Validation and maintenance of customized code can increase the demands on both internal IT staff and the software vendors

This figure shows how Metadata is collected in a standalone Metadata repository with its own internal Metadata store.  The internal store is populated through a scheduled import (arrows) of the Metadata from the various tools. In turn, the centralized repository exposes a portal for the end users to submit their queries. The Metadata portal passes the request to the centralized Metadata repository. The centralized repository will fulfill the request from the collected Metadata. In this type of implementation, the capability to pass the request from the user to various tools directly is not supported. Global search across the Metadata collected from the various tool is possible due to the collection of various Metadata in the centralized repository.