Re: A simple link, it turns out

dawn schrieb:

>>From August 2005 wired (sometime in the near future) a callout in the

Yes, in the RM we need to do almost everything manually (numerous joins and restrictions, hundreds of options) so it is nowadays a low level data manipulation and access technique rather than a high level data model. The RM knows almost nothing about our data and hence it cannot help us in many important tasks. If earlier (say, 10-20 years ago) it was used really as a high level data model then now it is used to model other data models. And for this purpose it is very efficient because of its powerful record matching, manipulation and transformation mechanisms. In particular, complete absence of *logical navigation* means (for example, by using links or automatic constraint propagation) is actually a verdict and restricts its use to the level of implementation of other models. In other words, the RM with respect to other (conceptual) data models is like assembly language or machine codes for OO languages. Data modelists and designers do not think now in terms of relations -- instead they use them (or other means) to implement higher level constructs. Indeed, if you have hundreds or even thousands of tables then will you build yourself an access path consisting of 10 or 20 tables? Even if you are an expert it will take a couple of pages of code and nobody will be able to understand and edit it in future. Conceptual models with *logical navigation* allow doing it in a couple of lines with absolutely predictable and clear result.

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