What is Meta-data?

Meta-data in most simple terms means "structured data about data" or "data that describes something (that may or may not itself be data)".

The prefix “meta” comes from the Greek and can indicate change, as in metamorphosis; or it can mean beyond or after, as in metaphysics. In information technology usage, the word meta-data has come to be used as a definition or description of data: a small indicator that encompasses and points to a larger piece of information. The library card catalog is the standard metaphor for meta-data: each card represented and led the user to a much larger body of information, the book or other item cataloged.

Meta-data has been around since the first program was written. The word meta-data was first recorded in the dictionary around 1980’s but its usage goes back all the way to 1960’s.


Why do we need to describe things?

  • “discover”: to find out that things exist
  • “locate”: to find out where things are
  • “request”: to ask for something
  • “access”: to get something – so we can use it

Meta-data provides us with a reference to useful data, and provides us with definitions that allow us to understand that data: its definition, its usages, its ownership, and its quality. Meta-data describes the processes and tools that maintain and act on that data. So meta-data goes beyond the traditional data dictionary or card catalog, and can describe the entire environment, which we have built to collect, maintain, and deploy our data assets.

Why do we need meta-data?

·        Poor documentation often leads to loss of critical information

·        To help you publicize and support the data or your organization

·        So you won't forget how you collected and processed your own data

·        So information is not lost when an employee leaves

·        So the data can be used again in the future

·        So you can tell if you need other's data and how to use it

·        To help allow your organization share data in a consistent way without duplication

·        To preserve the value of the data saving it from being useless due to changes to the data over time

·        To help new employees understand the organizations data with a smaller than normal learning curve

Some sources for Meta-data in an organization:

·        Conceptual, Logical and Physical Data Models

·        Business Definitions

·        Business Processes

·        Technical Definitions

·        Business Rules

·        Transformation Rules

·        Attribute Characteristics – field type, field size, etc.

·        Data Source System(s)

·        Data Creator

·        Data Purpose

·        Data Quality Rules

·        Data Quality Issues

·        and more

In conclusion, meta-data has broad applicability across the enterprise. There is virtually no process in the entire IT organization that can’t benefit from meta-data. In the next article I will try to dive deep into the types and sources of meta-data.


Bibliography:

Milstead, Jessica and Susan Feldman - “Meta-data: Cataloging by any other name ...” in Online, Jan/Feb 1999, p24–31. A very lucid description of what meta-data is and does, what the term means, and what the challenges are in implementing meta-data schemes.

D Gleason – “An Evolutionary Approach to Meta-data Management”