Definition
1. Metadata is data (information) that provides information about other data.
2. Three distinct types of metadata exist: structural metadata, descriptive metadata, and administrative metadata.
3. Metadata means "data about data". Although the "meta" prefix (from the Greek preposition and prefix μετά-) means "after" or "beyond", it is used to mean "about" in epistemology. Metadata is defined as the data providing information about one or more aspects of the data; it is used to summarize basic information about data which can make tracking and working with specific data easier. Some examples include: Means of creation of the data, Purpose of the data, Time and date of creation, Creator or author of the data, Location on a computer network where the data was created, Standards used, File size.
4. "metadata describes a resource for purposes such as discovery and identification. It can include elements such as title, abstract, author, and keywords."
5. "Metadata summarizes basic information about data, which can make finding and working with particular instances of data easier. For example, author, date created and date modified and file size are examples of very basic document metadata. Having the abilty to filter through that metadata makes it much easier for someone to locate a specific document."
Abbreviation
Synonyms
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Data
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Sources
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Metadata in oedb
In the oedb, the metadata is stored in a comment as a JSON string.
The SQL example is on GitHub.
There is a current development of a new OEP metadata version.
Different concepts for metadata were compared, harmonized and simplyfied:
-- metadata description
COMMENT ON TABLE model_draft.test_table IS '{
"title": "Good example title",
"description": "example metadata for example data",
"language": [ "eng", "ger", "fre" ],
"spatial":
{"location": "52.433405, 13.535666",
"extent": "europe",
"resolution": "100 m"},
"temporal":
{"reference_date": "2016-01-01",
"start": "2017-01-01",
"end": "2017-12-31",
"resolution": "hour"},
"sources": [
{"name": "eGo dataprocessing", "description": "", "url": "https://github.com/openego/data_processing", "license": "GNU Affero General Public License Version 3 (AGPL-3.0)", "copyright": "© Reiner Lemoine Institut"},
{"name": "", "description": "", "url": "", "license": "", "copyright": ""} ],
"license":
{"id": "ODbL-1.0",
"name": "Open Data Commons Open Database License 1.0",
"version": "1.0",
"url": "https://opendatacommons.org/licenses/odbl/1.0/",
"instruction": "You are free: To Share, To Create, To Adapt; As long as you: Attribute, Share-Alike, Keep open!",
"copyright": "© Reiner Lemoine Institut"},
"contributors": [
{"name": "Ludee", "email": "", "date": "2016-06-16", "comment": "Create metadata"},
{"name": "Ludee", "email": "", "date": "2016-11-22", "comment": "Update metadata"},
{"name": "Ludee", "email": "", "date": "2016-11-22", "comment": "Update header and license"},
{"name": "Ludee", "email": "", "date": "2017-03-16", "comment": "Add license to source"},
{"name": "Ludee", "email": "", "date": "2017-03-28", "comment": "Add copyright to source and license"},
{"name": "Ludee", "email": "", "date": "2017-05-30", "comment": "Update metadata to version 1.3"} ],
"resources": [
{"name": "model_draft.test_table",
"format": "sql",
"fields": [
{"name": "id", "description": "Unique identifier", "unit": "" },
{"name": "year", "description": "Reference year", "unit": "" },
{"name": "value", "description": "Example value", "unit": "MW" },
{"name": "geom", "description": "Geometry", "unit": "" }] }],
"metadata_version": "1.3"}';
-- select description
SELECT obj_description('model_draft.test_table' ::regclass) ::json;
