Essential fundamentals

Basic concepts

OpenKM has built-in with several types of nodes:

  • Folder.
  • Document.
  • Mail.
  • Record.

A node type folder  is a storage unit or a container. As a document, it also has a name but is not a fil, but it can contain documents, records and other folders into.

A node type document is a file. A document serves to establish one or several facts, and can be relied upon as a proof thereof.

A node type mail, most commonly referred to as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. A mail can contain documents ( in mail context are named attachments ).

In essence there are basically two kinds of nodes of type record:

  • Non-digital records.
  • Digital records.

A non-digital record is only a set of metadata groups.

A digital record can contains documents, mails, folders and other record into.

Non-digital record sample:

When OpenKM is used to store the location of papers in the real world. Each record only is a set of metadata fields that helps user to locate papers and there's not binary information associated ( like associated scanned document, etc. ).

Digital record sample:

OpenKM is used to store business records, where each record represents the result of some business process transaction. The digital record then, is used to store documents, mails associated with that process.

Understanding taxonomy, keywords, categories and metadata groups.

Spending time on nodes categorization is a good practice. A good categorization will help users quickly finding fast of the desired information, using  less time, saving money and being more efficient in your business process.

OpenKM helps you on it providing basically four ways for recategorizing your repository:

  • Taxonomy.
  • Keywords.
  • Categories.
  • Metadata groups.

You can use one of these features to categorize your repository or a combination of all.


The dictionary says:

"Taxonomy (from Greek taxis meaning arrangement or division and nomos meaning law) is the science of classification according to a pre-determined system, with the resulting catalogue used to provide a conceptual framework for discussion, analysis, or information retrieval. In theory, the development of a good taxonomy takes into account the importance of separating elements of a group (taxon) into subgroups (taxa) that are mutually exclusive, unambiguous, and taken together, include all possibilities."

Basically, a taxonomy is a way to group things together. Like a controlled vocabulary focuses on concepts, in practice, a good taxonomy should be simple, easy to remember, and easy to use.

For a best performance at UI we suggest - when possible - a taxonomy where each parent has 200 children or less.

Each folder in a taxonomy represents a "concept" and lists a couple of nodes ( folders, documents, mails or records ) associated within.


A keyword, in the context of document management is a particular word or phrase that describes the contents. Setting keywords is the most simple and basic system to categorizing the nodes in your repository but at same time is the less powerfull. For large repositories we encourage using metadata groups.

Limitations of keywords usage:

  • When you have thousands of keywords  searching by keywords can be inefficient ( not able to refine search and you get a lot of results with same keywords, the users not followed a restricted way to catalog ). A tag cloud diagram in this cases is usually an unusable graphical representation of keywords.
  • It's difficult for the users setting keywords because they do not know all the keyword dictionary of the company.
  • Users write keywords in similar way but not always the same ( for example users use the words "building", "construction" and "edifice" indistinctly ).

You can get best results when:

  • You limit the number of users who are able to set keywords.
  • You use a controlled keywords dictionary ( more information at ).
  • You share a complete company keywords dictionary to your users. That helps understanding how is mapped the knowledge in your organization and helps users finding it.


In OpenKM, the categories are a virtual taxonomy that helps on navigation of taxonomy nodes across other concepts. Each category node represents a "concept" and list a couple of nodes ( folders, documents, mails or records ) associated within.

We suggest using categories rather than keywords.


Metadata groups are data that describes other data providing information about a certain nodes content. Metadata groups helps on creating controlled classification and a powerful way to locate nodes and refine query searchs.

With metadata groups you can simulate the keywords and categories features. We encourage expend some time investigating metadata feature and we suggest use it rather keywords and categories.