The Relational Database Dictionary

Technical Issues

The following list summarizes key technical issues underlying the presentation of terms, concepts, and examples in the dictionary:

1. Keywords, variable names, and the like are set in all uppercase throughout.

2. Coding examples are expressed (mostly) in a language called Tutorial D. I believe those examples are reasonably self-explanatory, but in any case the Tutorial D language is largely defined in the dictionary itself, in the entries for the various relational operators (union, join, restriction, etc.). If needed, a comprehensive description of the language can be found in the book Databases, Types, and the Relational Model: The Third Manifesto, Third Edition, by C. J. Date and Hugh Darwen (Addison-Wesley). Note: As the subtitle indicates, that book also introduces and explains The Third Manifesto, a precise though somewhat formal definition of the relational model and a supporting type theory (including a comprehensive model of type inheritance). In particular, it uses the name D as a generic name for any language that conforms to the principles laid down by The Third Manifesto. Any number of distinct languages could qualify as a valid D; sadly, however, SQL isn’t one of them, which is why examples in this dictionary are expressed in Tutorial D and not SQL. (Tutorial D is, of course, a valid D.)

3. Following on from the previous point, I should make it clear that all relational definitions in this dictionary are intended to conform fully to the relational model as defined ...