The benefits of metadata and implementing a metadata management strategy

This section of the chapter excerpt will introduce and explore the basics of metadata.

By: Alex Berson and Larry Dubov

Service provider takeaway: metadata provides several important benefits to data management consultants. This section of the chapter excerpt from the book Mastering Data Management and Customer Integration for a Global Enterprise will look at some of these benefits of metadata.

Download the .pdf of the chapter here.

Metadata Basics

In simple terms, metadata is "data about data," and if managed properly, it is generated whenever data is created, acquired, added to, deleted from, or updated in any data store and data system in scope of the enterprise data architecture.

Metadata provides a number of very important benefits to the enterprise, including:

  • Consistency of definitions Metadata contains information about data that helps reconcile the difference in terminology such as "clients" and "customers," "revenue" and "sales," etc.
  • Clarity of relationships Metadata helps resolve ambiguity and inconsistencies when determining the associations between entities stored throughout data environment. For example, if a customer declares a "beneficiary" in one application, and this beneficiary is called a "participant" in another application, metadata definitions would help clarify the situation.
  • Clarity of data lineage Metadata contains information about the origins of a particular data set and can be granular enough to define information at the attribute level; metadata may maintain allowed values for a data attribute, its proper format, location, owner, and steward. Operationally, metadata may maintain auditable information about users, applications, and processes that create, delete, or change data, the exact timestamp of the change, and the authorization that was used to perform these actions.

There are three broad categories of metadata:

  • Business metadata includes definitions of data files and attributes in business terms. It may also contain definitions of business rules that apply to these attributes, data owners and stewards, data quality metrics, and similar information that helps business users to navigate the "information ocean." Some reporting and business intelligence tools provide and maintain an internal repository of business-level metadata definitions used by these tools.
  • Technical metadata is the most common form of metadata. This type of metadata is created and used by the tools and applications that create, manage, and use data. For example, some best-in-class ETL tools maintain internal metadata definitions used to create ETL directives or scripts. Technical metadata is a key metadata type used to build and maintain the enterprise data environment. Technical metadata typically includes database system names, table and column names and sizes, data types and allowed values, and structural information such as primary and foreign key attributes and indices. In the case of CDI architecture, technical metadata will contain subject areas defining attribute and record location reference information.
  • Operational metadata contains information that is available in operational systems and run-time environments. It may contain data file size, date and time of last load, updates, and backups, names of the operational procedures and scripts that have to be used to create, update, restore, or otherwise access data, etc.

All these types of metadata have to be persistent and available in order to provide necessary and timely information to manage often heterogeneous and complex data environments such as those represented by various Data Hub architectures. A metadata management facility that enables collection, storage, maintenance, and dissemination of metadata information is called a metadata repository.

Topologically, metadata repository architecture defines one of the following three styles:

  • Centralized Metadata repository
  • Distributed Metadata repository
  • Federated or Hybrid Metadata repository

The centralized architecture is the traditional approach to building a metadata repository. It offers efficient access to information, adaptability to additional data stores, scalability to capture additional metadata, and high performance. However, like any other centralized architecture, centralized metadata repository is a single point of failure. It requires continuous synchronization with the participants of the data environment, may become a performance bottleneck, and may negatively affect quality of metadata. Indeed, the need to copy information from various applications and data stores into the central repository may compromise data quality if the proper data validation procedures are not a part of the data acquisition process.

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A distributed architecture avoids the concerns and potential errors of maintaining copies of the source metadata by accessing up-to-date metadata from all systems' metadata repositories in real time. Distributed metadata repositories offer superior metadata quality since the users see the most current information about the data. However, since distributed architecture requires real-time availability of all participating systems, a single system failure may potentially bring the metadata repository down. Also, as source systems configurations change, or as new systems become available, a distributed architecture needs to adapt rapidly to the new environment, and this degree of flexibility may require a temporary shutdown of the repository.

A federated or a hybrid approach leverages the strengths and mitigates the weaknesses of both distributed and centralized architectures. Like a distributed architecture, the federated approach can support real-time access of metadata from source systems. It can also centrally and reliably maintain metadata definitions or at least references to the proper locations of the accurate definitions in order to improve performance and availability.

Regardless of the architecture style of the metadata repository, any implementation should recognize and address the challenge of semantic integration. This is a well-known problem in metadata management that manifests itself in the system's inability to integrate information properly because some data attributes may have similar definitions but have completely different meanings. The reverse is also true. A trivial example is the task of constructing an integrated view of the office staff hierarchy for a company that was formed because of a merge of two entities. If you use job titles as a normalization factor, a "Vice President" in one company may be equal to a "Partner" in another. Not having these details explained clearly in the context becomes a difficult problem to solve systematically. The degree of difficulty grows with the diversity of the context. Among the many approaches to solving this challenge is the metadata repository design that links the context to the information itself and the rules by which this context should be interpreted.

Enterprise Information Integration and Integrated Data Views

Enterprise Information Integration (EII) is a set of technologies that leverage information collected and stored in the enterprise metadata repository to deliver accurate, complete, and correct data to all authorized consumers of such information without the need to create or use persistent data storage facilities. The fundamental premise of EII is to enable authorized users to just-in-time and transparent access to all information they are entitled to.

Conceptually, EII technologies complement other solutions found in the Information Consumer zone by defining and delivering virtualized views of integrated data that can be distributed across several data stores including a Data Hub.

EII data views are based on the data requests and metadata definitions of the data under management. These views are independent from the technologies of the physical data stores used to construct these views.

Moreover, advanced EII solutions can support information delivery across a variety of channels including the ability to render the result set on any computing platform, including various mobile devices. Looking at EII from a CDI Data Hub architecture viewpoint, and applying service-oriented architecture principles, we can categorize EII technologies as components of the Information Consumer zone. The EII components that deliver requested data views to the consumers (users or applications) should be designed, implemented, and supported in conjunctions with the data location and delivery services depicted in Figure 6-2.

Although, strictly speaking, EII is not a mandatory part of the Data Hub architecture, it is easy to see that using EII services allows a Data Hub to deliver the value of an integrated information view to the consuming applications and users more quickly, at a lesser cost, and in a more flexible and dynamic fashion.

In other words, a key part of any CDI Data Hub design is the capability of delivering data to consuming applications periodically and on demand in agreed-upon formats. But being able to deliver data from the Data Hub is not the only requirement for the Information Consumer zone. Many organizations are embarking on the evolutionary road to a Data Hub design and implementation that makes the Data Hub a source for analytical and operational data management including support for the Business Intelligence and Servicing CRM systems. This approach expands the role of the Data Hub from the data integration target to the master data source that feeds value-added business applications. This expanded role of the Data Hub and the increased information value of data managed by the Data Hub require an organizational recognition of the importance of enterprise data strategy, broad data governance, clear and actionable data quality metrics with specially appointed data stewards that represent business units, and the existence and continuous support of an enterprise metadata repository.

The technical, business, and organizational concerns of data strategy, data governance, data management and data delivery that were discussed in this and the previous chapter are some of the key factors necessary to make any CDI initiative a useful, business-value-enhancing proposition.

Data Management Concerns of MDM-CDI Architecture
  Data Strategy
  Data Quality
  Managing Data in the Data Hub
  Overview of Business Rules Engines
  Metadata Basics

About the book

Master Data Management and Customer Data Integration for a Global Enterprise explains how to grow revenue, reduce administrative costs, and improve client retention by adopting a customer-focused business framework. Learn to build and use customer hubs and associated technologies, secure and protect confidential corporate and customer information, provide personalized services, and set up an effective data governance team. Purchase the book from McGraw-Hill Osborne Media.

Reprinted with permission from McGraw-Hill from Master Data Management and Customer Data Integration for the Global Enterprise by Alex Berson and Larry Dubov (McGraw-Hill, 2007)

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