Ideal Definition vs Declaration

Definition vs Declaration

To define something is to spend time in an ideal world where anything is possible and you can imagine, re-arrange and visualise the definition into anything you want. It becomes the ‘Ideal Definition’ of your goal, a masterpiece waiting to take form.

The sharing of this ideal definition becomes limited by the declared method of expression.

Pictures work well but are limited by the readers’ ability to understand what they have visualised in their mind. The use of visual tools requires an assumption of minimum understanding placed upon the consumer of the picture or a built-up story to get them there, like a Dilbert comic.

Languages (text symbols) in all forms work well but also have an assumed minimum understanding placed upon the reading of that written word. A story with index, footnotes, glossary and references work well to fill in any gaps of understanding; allowing the reader to jump all over the document in their quest for that ‘Ah, ha; I get it!’ moment.

“a declared implementation is always the lesser,
imperfect representation of the defined ideal”

Programming languages are a stricter implementation of a language that limits the expression to a maximum number of combinations. This is a limited syntax that can be learned and does not grow beyond the maximum of combinations of the keywords involved in the syntax. Programming languages are primarily focused on the flow of change.

Databases are a stricter implementation of a language that provides a limit of maximum combinations of expression with a primary focus on storage. Programming languages are used to control the flow of symbols in and out of a database. With these two limited forms of expression of language we now have a partnership, a duo, a team that can provide useful functionality.

Welcome to Data Warehousing, a way to access a lot of stored information and a way to change it.

The implementation of the ideal definition can take many different forms, each providing their own features complete with advantages and compromises. The expression of a definition into form is when it becomes ‘Declared’.

It can be said that all things have two or more perspectives, the defined ideal and the declared implementation(s). The variety of different available solutions comes from the gap between ‘the defined versus the declared’. This variance is incorporated into a lot of basic concepts:

This basic difference has significant implications on the usable features of a form; both within itself and its interaction with others. A good example of this is the native data type called ‘String’:

The main difference between them is based upon the experience when used. Each has a significant impact on the features and complexity of the run time environment. Considering:

The above example highlights the diversity between a defined ideal of a ‘String’ and its multiple declared implementations that can offer different features, advantages and compromises. The choice of which declared implementation to use comes back to which technical debt are you willing to live with?

In the world of SAP Netweaver Business Warehouse (SAP BW) a lot of these initial choices have been made for you to leverage, as delivered/installed. The declared implementations have been wrapped up into a framework ready for use:

The art of being an SAP BW Professional is to understand these pre-built definitions and declarations:

Question: What other examples can I think of where the difference between definition and declaration is evident within BW?

Perhaps Modified (M) versus Active (A) objects for data storage or Transported (T) objects used by the Transport Management System (TMS).

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