A Metadata repository is a database created to gather, store, and distribute contextual information about business data, when documented it is known as metadata. This contextual information of business data include meaning and content, policies that govern, technical attributes, specifications that transform, and programs that manipulate.[1]
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The metadata repository is responsible for physically storing and cataloging metadata. The metadata that is stored should be generic, integrated, current, and historical. Generic for a metadata repository means that the meta model should store the metadata by generic terms instead of storing it by an applications-specific defined way, so that if your data base standard changes from one product to another the physical meta model of the metadata repository would not need to change. Integration of the metadata repository allows all entities of the enterprise business to view all metadata subject areas. The metadata repository should also be designed so that current and historical metadata both can be accessed.[2] Metadata repositories use to be referred to as a data dictionary.[3]
A metadata repository is similar to a metadata registry in that they only store metadata. The metadata repository is different from a metadata registry in that a repository provides response times suitable for browsing and reporting, while registries provides response times suitable for service virtualization.[4]
Each database management system (DBMS) and database tools have their own language for the metadata components within. Database applications already have their own repositories or registries that are expected to provide all of the necessary functionality to access the data stored within. Vendors do not want other companies to be capable of easily migrating data away from their products and into competitors products, so they are proprietary with the way the handle metadata . CASE tools, DBMS dictionaries, ETL tools, data-cleansing tools, OLAP tools, and data mining tools all handle and store metadata differently. Only a metadata repository can be designed to store the metadata components from all of these tools.[5]
Metadata repositories should store metadata in four classifications: ownership, descriptive characteristics, rules and policies, and physical characteristics. Ownership, showing the data owner and the application owner. The descriptive characteristics, define the names, types and lengths, and definitions describing business data or business processes. Rules and policies, will define security, data cleanliness, timelines for data, and relationships. Physical characteristics define the origin or source, and physical location.[6] Like building a logical data model for creating a database, a logical meta model can help identify the metadata requirements for business data.[7] The metadata repository will be centralized, decentralized, or distributed.
Metadata repositories can be designed as either a Entity-relationship model, or an Object-oriented design.
If you choose not to build your own Metadata repository here are some vendors who can.
*Troux Technologies