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Metadata has been identified as a key success factor in data warehouse projects. It captures all kinds of information necessary to analyse, design, build, use, and interpret the data warehouse contents. In order to spread the use of metadata, enable the interoperability between repositories, and tool integration within data warehousing architectures, a standard for metadata representation and exchange is needed. This paper considers two standards and compares them according to specific areas of interest within data warehousing. Despite their incontestable similarities, there are significant differences between the two standards which would make their unification difficult.

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Metadata has been identified as a key success factor in data warehouse projects. It captures all kinds of information necessary to design, build, use and interpret the data warehouse contents. This paper gives an overview about the role metadata plays for data warehousing and reviews existing standards, commercial solutions and research actions relevant to metadata management. It turns out that an overall solution for managing all metadata in a central or federated repository is still missing regarding a global metadata schema as well as system aspects and interoperability among involved tools producing metadata. The divergence of proposed standards will probably prevent a breakthrough within the near future.

Capturing, representing and processing metadata promises to facilitate the management, consistent use and understanding of data and thus better support the exploitation of masses of information that is available online today. Despite the increasing interest in metadata management, its purpose, requirements and problems are still not clear: This is particularly true in the area of data warehousing. The reasons are multiple. Compared to the past, today's metadata management considers a sign$cantly larger spectrum ~ of information (including even certain pieces of programs).Moreovec metadata are produced by various tools and reside in different sources which need to be integrated in order to ensure consistency and provide uniform access, impact analysis and data tracking. Existing work has only partially covered some of these aspects. This paper summarizes the most important issues of metadata management for data warehousing, including the role of metadata and solved and unsolved problems of the available solutions. The design of an appropriate information model, metadata integration and advanced user interaction facilities are crucial questions to be answered.