Defining Data

Data is defined in terms of:

• Master Data
• Meta Data

Master Data

Master data refers to reference information that is key to the operation of business.

This key business information includes data about customers, products, employees, materials, suppliers, etc. and is mostly non-transactional. Master data may however support transactional processes and operations.

Master data defines how the business operates – the business objects, definitions, classifications, and terminology that describe business information as well as the context for recording transaction data.

Master data forms the foundation of analytics and reporting and for this purpose, it is stored in a data warehouse or data marts.

An important part of any BI Program is the agreement of persistent, non-transactional Master Data that defines a business entity.

Master Data is managed by the discipline of Master Data Management [MDM].

Meta Data

In simple terms, Metadata is essentially data about data. A more sophisticated defintion may be - Metadata is structured, encoded data that describe characteristics of information-bearing entities to aid in the identification, discovery, assessment, and management of the described entities.

In terms of Business Intelligence Systems, meta data is used by the database processor to determine whether an item of collection of data will meet the query defined by the user. In this way, Metadata is used to facilitate the understanding, use and management of data.

Metadata may describe an individual datum, a content item, or a collection of data.

The metadata required for effective data management varies with the type of data and context of use.

In an information system, data is the content of the computer files, metadata refers to an individual data item. This would typically include the name of the field and its length.

Metadata about a collection of data items typically includes the name of the file, the type of file and the name of the data administrator.

Types of Metadata

Metadata can be classified by:

• Content - Metadata can either describe the resource itself [name and size of a file] or the content of the resource [This image shows ..."].
• Mutability - in terms of the complete resource, metadata can be either immutable [the "Title" of a video does not change as the video itself is being played] or mutable (the "Scene description" does change].
• Logical Function - there are three layers of logical function:
  
  • Bottom subsymbolic layer that contains the raw data itself
  • Middle symbolic layer with metadata describing the raw dat
  • Top logical layer containing metadata that allows logical reasoning using the symbolic layer.

More on Types of Metadata

Metadata Hierarchy

Metadata may be structured into a hierarchy - called an ontology or schema.

Metadata is frequently stored in a central location and used to help organizations standardize their data. This information is typically stored in a metadata registry.

Difference Between Data And Metadata

It is often difficult to distinguish between raw data and metadata because:

• Something can be data and metadata at the same time - the headline of an article is both its title (metadata) and part of its text (data).
• Data and metadata can change their roles - a poem would be regarded as data, but if used as lyrics for a song, the entire poem could be attached to an audio file of the song as metadata. Thus data / metadata is very much contextual in defintion.
• Metadata is infinite - metadata itself is data, it is possible to create metadata about metadata, metadata about metadata about metadata and so on. For this reason, it is essential to archive metadata about metadata, to keep track of where the metadata originated from when merging two documents.

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