Data virtualization has emerged in the 2000s as the new software technology to complete the virtualization "stack" in the enterprise. Metadata is used in data virtualization servers which are enterprise infrastructure components, alongside database and application servers. Metadata in these servers is saved as persistent repository and describe "business objects in various enterprise systems and applications. Structural metadata commonality is also important to support data virtualization.
Standardization work has had a large impact on efforts to build metadata systems in the statistical community["citation needed]. Several metadata standards["which?] are described, and their importance to statistical agencies is discussed. Applications of the standards["which?] at the Census Bureau, Environmental Protection Agency, Bureau of Labor Statistics, Statistics Canada, and many others are described["citation needed]. Emphasis is on the impact a metadata registry can have in a statistical agency.
Metadata has been used in various ways as a means of cataloging items in libraries in both digital and analog format. Such data helps classify, aggregate, identify, and locate a particular book, DVD, magazine or any object a library might hold in its collection. Until the 1980s, many library catalogues used 3x5 inch cards in file drawers to display a book's title, author, subject matter, and an abbreviated "alpha-numeric string ("call number) which indicated the physical location of the book within the library's shelves. The "Dewey Decimal System employed by libraries for the classification of library materials by subject is an early example of metadata usage. Beginning in the 1980s and 1990s, many libraries replaced these paper file cards with computer databases. These computer databases make it much easier and faster for users to do keyword searches. Another form of older metadata collection is the use by US Census Bureau of what is known as the "Long Form." The Long Form asks questions that are used to create demographic data to find patterns of distribution. "Libraries employ metadata in "library catalogues, most commonly as part of an "Integrated Library Management System. Metadata is obtained by "cataloguing resources such as books, periodicals, DVDs, web pages or digital images. This data is stored in the integrated library management system, "ILMS, using the "MARC metadata standard. The purpose is to direct patrons to the physical or electronic location of items or areas they seek as well as to provide a description of the item/s in question.
More recent and specialized instances of library metadata include the establishment of "digital libraries including "e-print repositories and digital image libraries. While often based on library principles, the focus on non-librarian use, especially in providing metadata, means they do not follow traditional or common cataloging approaches. Given the custom nature of included materials, metadata fields are often specially created e.g. taxonomic classification fields, location fields, keywords or copyright statement. Standard file information such as file size and format are usually automatically included. Library operation has for decades been a key topic in efforts toward "international standardization. Standards for metadata in digital libraries include "Dublin Core, "METS, "MODS, "DDI, "DOI, "URN, "PREMIS schema, "EML, and "OAI-PMH. Leading libraries in the world give hints on their metadata standards strategies.
Metadata in a museum context is the information that trained cultural documentation specialists, such as "archivists, "librarians, museum "registrars and "curators, create to index, structure, describe, identify, or otherwise specify works of art, architecture, cultural objects and their images.["page needed]["page needed] Descriptive metadata is most commonly used in museum contexts for object identification and resource recovery purposes.
Metadata is developed and applied within collecting institutions and museums in order to:
Many museums and cultural heritage centers recognize that given the diversity of art works and cultural objects, no single model or standard suffices to describe and catalogue cultural works. For example, a sculpted Indigenous artifact could be classified as an artwork, an archaeological artifact, or an Indigenous heritage item. The early stages of standardization in archiving, description and cataloging within the museum community began in the late 1990s with the development of standards such as Categories for the Description of Works of Art (CDWA), Spectrum, the Conceptual Reference Model (CIDOC), Cataloging Cultural Objects (CCO) and the CDWA Lite XML schema. These standards use "HTML and "XML markup languages for machine processing, publication and implementation. The Anglo-American Cataloguing Rules (AACR), originally developed for characterizing books, have also been applied to cultural objects, works of art and architecture. Standards, such as the CCO, are integrated within a Museum's Collection Management System (CMS), a database through which museums are able to manage their collections, acquisitions, loans and conservation. Scholars and professionals in the field note that the "quickly evolving landscape of standards and technologies" create challenges for cultural documentarians, specifically non-technically trained professionals.["page needed] Most collecting institutions and museums use a "relational database to categorize cultural works and their images. Relational databases and metadata work to document and describe the complex relationships amongst cultural objects and multi-faceted works of art, as well as between objects and places, people and artistic movements. Relational database structures are also beneficial within collecting institutions and museums because they allow for archivists to make a clear distinction between cultural objects and their images; an unclear distinction could lead to confusing and inaccurate searches.
An object's materiality, function and purpose, as well as the size (e.g., measurements, such as height, width, weight), storage requirements (e.g., climate-controlled environment) and focus of the museum and collection, influence the descriptive depth of the data attributed to the object by cultural documentarians. The established institutional cataloging practices, goals and expertise of cultural documentarians and database structure also influence the information ascribed to cultural objects, and the ways in which cultural objects are categorized. Additionally, museums often employ standardized commercial collection management software that prescribes and limits the ways in which archivists can describe artworks and cultural objects. As well, collecting institutions and museums use "Controlled Vocabularies to describe cultural objects and artworks in their collections. Getty Vocabularies and the Library of Congress Controlled Vocabularies are reputable within the museum community and are recommended by CCO standards. Museums are encouraged to use controlled vocabularies that are contextual and relevant to their collections and enhance the functionality of their digital information systems. Controlled Vocabularies are beneficial within databases because they provide a high level of consistency, improving resource retrieval. Metadata structures, including controlled vocabularies, reflect the "ontologies of the systems from which they were created. Often the processes through which cultural objects are described and categorized through metadata in museums do not reflect the perspectives of the maker communities.
Metadata has been instrumental in the creation of digital information systems and archives within museums, and has made it easier for museums to publish digital content online. This has enabled audiences who might not have had access to cultural objects due to geographic or economic barriers to have access to them. In the 2000s, as more museums have adopted archival standards and created intricate databases, discussions about "Linked Data between museum databases have come up in the museum, archival and library science communities. Collection Management Systems (CMS) and "Digital Asset Management tools can be local or shared systems. "Digital Humanities scholars note many benefits of interoperability between museum databases and collections, while also acknowledging the difficulties achieving such interoperability.
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Problems involving metadata in "litigation in the "United States are becoming widespread.["when?] Courts have looked at various questions involving metadata, including the "discoverability of metadata by parties. Although the Federal Rules of Civil Procedure have only specified rules about electronic documents, subsequent case law has elaborated on the requirement of parties to reveal metadata. In October 2009, the "Arizona Supreme Court has ruled that metadata records are "public record. Document metadata have proven particularly important in legal environments in which litigation has requested metadata, which can include sensitive information detrimental to a certain party in court. Using "metadata removal tools to "clean" or redact documents can mitigate the risks of unwittingly sending sensitive data. This process partially (see "data remanence) protects law firms from potentially damaging leaking of sensitive data through "electronic discovery.
In Australia the need to strengthen national security has resulted in the introduction of a new metadata storage law. This new law means that both security and policing agencies will be allowed to access up to two years of an individual's metadata, supposedly to make it easier to stop any terrorist attacks and serious crimes from happening.
Australian medical research pioneered the definition of metadata for applications in health care. That approach offers the first recognized attempt to adhere to international standards in medical sciences instead of defining a proprietary standard under the "World Health Organization (WHO) umbrella. The medical community yet did not approve the need to follow metadata standards despite research that supported these standards.
"Data warehouse (DW) is a repository of an organization's electronically stored data. Data warehouses are designed to manage and store the data. Data warehouses differ from "business intelligence (BI) systems, because BI systems are designed to use data to create reports and analyze the information, to provide strategic guidance to management. Metadata is an important tool in how data is stored in data warehouses. The purpose of a data warehouse is to house standardized, structured, consistent, integrated, correct, "cleaned" and timely data, extracted from various operational systems in an organization. The extracted data are integrated in the data warehouse environment to provide an enterprise-wide perspective. Data are structured in a way to serve the reporting and analytic requirements. The design of structural metadata commonality using a "data modeling method such as "entity relationship model diagramming is important in any data warehouse development effort. They detail metadata on each piece of data in the data warehouse. An essential component of a "data warehouse/"business intelligence system is the metadata and tools to manage and retrieve the metadata. "Ralph Kimball["page needed] describes metadata as the DNA of the data warehouse as metadata defines the elements of the "data warehouse and how they work together.
"Kimball et al. refers to three main categories of metadata: Technical metadata, business metadata and process metadata. Technical metadata is primarily definitional, while business metadata and process metadata is primarily descriptive. The categories sometimes overlap.
The "HTML format used to define web pages allows for the inclusion of a variety of types of metadata, from basic descriptive text, dates and keywords to further advanced metadata schemes such as the "Dublin Core, "e-GMS, and AGLS standards. Pages can also be "geotagged with "coordinates. Metadata may be included in the page's header or in a separate file. "Microformats allow metadata to be added to on-page data in a way that regular web users do not see, but computers, "web crawlers and "search engines can readily access. Many search engines are cautious about using metadata in their ranking algorithms due to exploitation of metadata and the practice of search engine optimization, "SEO, to improve rankings. See "Meta element article for further discussion. This cautious attitude may be justified as people, according to Doctorow, are not executing care and diligence when creating their own metadata and that metadata is part of a competitive environment where the metadata is used to promote the metadata creators own purposes. Studies show that search engines respond to web pages with metadata implementations, and Google has an announcement on its site showing the meta tags that its search engine understands. Enterprise search startup "Swiftype recognizes metadata as a relevance signal that webmasters can implement for their website-specific search engine, even releasing their own extension, known as Meta Tags 2.
In "broadcast industry, metadata is linked to audio and video "broadcast media to:
This metadata can be linked to the video media thanks to the "video servers. Most major broadcast sport events like "FIFA World Cup or the "Olympic Games use this metadata to distribute their video content to "TV stations through "keywords. It is often the host broadcaster who is in charge of organizing metadata through its International Broadcast Centre and its video servers. This metadata is recorded with the images and are entered by metadata operators (loggers) who associate in live metadata available in metadata grids through "software (such as "Multicam(LSM) or "IPDirector used during the FIFA World Cup or Olympic Games).
Metadata that describes geographic objects in electronic storage or format (such as datasets, maps, features, or documents with a geospatial component) has a history dating back to at least 1994 (refer MIT Library page on FGDC Metadata). This class of metadata is described more fully on the "geospatial metadata article.
Ecological and environmental metadata is intended to document the "who, what, when, where, why, and how" of data collection for a particular study. This typically means which organization or institution collected the data, what type of data, which date(s) the data was collected, the rationale for the data collection, and the methodology used for the data collection. Metadata should be generated in a format commonly used by the most relevant science community, such as "Darwin Core, "Ecological Metadata Language, or "Dublin Core. Metadata editing tools exist to facilitate metadata generation (e.g. Metavist, "Mercury: Metadata Search System, Morpho). Metadata should describe "provenance of the data (where they originated, as well as any transformations the data underwent) and how to give credit for (cite) the data products.
When first released in 1982, Compact Discs only contained a Table Of Contents (TOC) with the number of tracks on the disc and their length in samples. Fourteen years later in 1996, a revision of the "CD Red Book standard added "CD-Text to carry additional metadata. But CD-Text was not widely adopted. Shortly thereafter, it became common for personal computers to retrieve metadata from external sources (e.g. "CDDB, "Gracenote) based on the TOC.
Digital "audio formats such as "digital audio files superseded music formats such as "cassette tapes and "CDs in the 2000s. Digital audio files could be labelled with more information than could be contained in just the file name. That descriptive information is called the audio tag or audio metadata in general. Computer programs specializing in adding or modifying this information are called "tag editors. Metadata can be used to name, describe, catalogue and indicate ownership or copyright for a digital audio file, and its presence makes it much easier to locate a specific audio file within a group, typically through use of a search engine that accesses the metadata. As different digital audio formats were developed, attempts were made to standardize a specific location within the digital files where this information could be stored.
As a result, almost all digital audio formats, including "mp3, broadcast wav and "AIFF files, have similar standardized locations that can be populated with metadata. The metadata for compressed and uncompressed digital music is often encoded in the "ID3 tag. Common editors such as "TagLib support MP3, Ogg Vorbis, FLAC, MPC, Speex, WavPack TrueAudio, WAV, AIFF, MP4, and ASF file formats.
With the availability of "Cloud applications, which include those to add metadata to content, metadata is increasingly available over the Internet.
Metadata can be stored either internally, in the same file or structure as the data (this is also called embedded metadata), or externally, in a separate file or field from the described data. A data repository typically stores the metadata detached from the data, but can be designed to support embedded metadata approaches. Each option has advantages and disadvantages:
Metadata can be stored in either human-readable or binary form. Storing metadata in a human-readable format such as "XML can be useful because users can understand and edit it without specialized tools. However, text-based formats are rarely optimized for storage capacity, communication time, or processing speed. A binary metadata format enables efficiency in all these respects, but requires special software to convert the binary information into human-readable content.
Each "relational database system has its own mechanisms for storing metadata. Examples of relational-database metadata include:
In database terminology, this set of metadata is referred to as the "catalog. The "SQL standard specifies a uniform means to access the catalog, called the "information schema, but not all databases implement it, even if they implement other aspects of the SQL standard. For an example of database-specific metadata access methods, see "Oracle metadata. Programmatic access to metadata is possible using APIs such as "JDBC, or SchemaCrawler.
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