There is a point to this anecdote. Provenance was the word used back then to describe the origins and the nature of objects. If I unearth an artifact and I take it out of its context, that is, I remove it from the site, what would happen to its scientific value?
That depends on how well I describe that provenance and if I use the right keywords and organizational principles that are used to categorize, describe, analyze and curate similar objects and artifacts.
This is why looting of archaeological sites is so damaging. Not only is the object lost but even if recovered it has lost its provenance or meaning! This anecdote hopefully starts to form an idea that data on the data is as important as the data itself. Without having context, data has little reuse value. Using the context of my job as an archaeologist, an object loses its scientific value if it loses its provenance or metadata.
Every artifact is bagged and tagged using a numerical reference on the bag that corresponds to notes in a log. Often there are photos and sketches made of the artifact in-situ in its original state for future research. Archaeology is not about treasure hunting. Both endeavors are fun and exciting. But the useful side of both open data and Archaeology is about the amount of reuse we can derive from our objects whether they be stones and bones or massive datasets. Now that we have a more basic answer to our original question "what is metadata", let's take a look at what others have had to say.
I use two definitions as a reference: one from the International Standards Organization ISO , the other from White House Roundtables that I attended both on Data Quality and on open data for Public-Private Collaboration , as we co-constructed a definition in the presence of experts. First, provenance in the White House context is defined as the metadata of a dataset. The second difference is that there is no "timeliness" dimension to the ISO definition of Data Quality.
The ISO predates the widespread adoption of open data. Perhaps timeliness will become a part of the ISO in the future. To make this easier to discuss, we will conflate the definitions of provenance and semantics into a third term called metadata. According to Liu and Ram's " A semiotic Framework for Analyzing Data Provenance Research ", the word provenance used in the context of data has different meanings for different people.
Liu and Ram go on to define the semantic model of provenance in this and several other works as a seven piece conceptual model. Liu and Ram conceptualize data provenance as consisting of seven interconnected elements including what, when, where, who, how, which, and why. These are elements of several metadata frameworks.
Basically, most metadata schemas ask these elements about their data. So, if we conflate these two terms into metadata, we are saying that metadata gives the following information about the data it models or represents:. Opendatasoft natively uses a subset of DCAT to describe datasets. The following metadata is available:. The creation of a fully custom metadata template can also be done. A lot of the discussions around data quality and data discoverability have revolved around metadata and something called ontologies.
Ontologies are descriptions and definitions of relationships. Ontologies help us to understand the relationship between things. As an example, an "android phone" is a subject of an object class, "cell phone". Some refer to an "ontology spectrum" that describes some frameworks as weak and others as strong. This "spectrum" encapsulates the range of opinions as to what an ontology really is. Every word processing software collects some standard metadata and enables you to add your own fields for each document.
Typical fields are:. Relational databases most common type of database store and provide access not only data but also metadata in a structure called data dictionary or system catalog.
It holds information about:. All the fields you see by each file in file explorer is actually metadata. The actual data is inside those files. Metadata includes:. Paper document files have often administrative metadata that help manage documents. This might include:. Those were my examples. I hope by now you have pretty good understanding of what metadata is.
If you are looking for a solution that will help you manage your metadata, check out Dataedo - metadata management software. Most database management systems keep the data dictionary hidden from users to prevent them from accidentally destroying its contents. We can access those views using plain SQL statements. Technical Metadata — This type of metadata defines database system names, tables names, table size, data types, values, and attributes.
Further technical metadata also includes some constraints like foreign key, primary key, and indices. Business Metadata — It consists of the ownership of data, changing policies, business rules and regulations, and other business details. This type of metadata is said to a specific business. Descriptive Metadata — Descriptive metadata describes any file, folder, book, image, or video. It may include details of knowledge like title, author, date, size, author name, published on, and similarly others.
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