Re: chooses not to generate code at all

Responding to Frebe...

The DBMS exists to provide persistence for data. 


There are many applications that would need a (R)DBMS even if
persistence is not needed. Two very important features in a RDBMS that
has nothing to do with persistence is queries and transactions.

Queries are simply a particular data access mechanism (i.e., an interface to the persistence engine). While queries are convenient for accessing the RDM via access infrastructures like SQL, there would be no reason to employ queries if one were not accessing RDB persistence through such infrastructures.

DB transactions (as opposed to business transactions like debits/credits to a GL) are necessarily part of the DBMS responsibilities because of the realities of physical storage -- data integrity would be impossible without them. The application, unfortunately, needs to be aware of DB transactions because of the limitations of the DBMS technology but it certainly isn't a service of value to the application for solving the customer's problem.

[In case you are thinking in terms of business transactions, I would point out that the business transaction processing paradigm dates from the days of mag tape -- long before the RDM was invented. One could argue that Codd was really adapting that model to persistence in a direct access environment when he came up with the RDM.]

Much more important,
the value of the RDM is that the data can be stored in a manner that is
completely independent of its use.



It might be possible, but when you design a relational schema, you need
to know how the data should be used.

Only to the extent of deliberately denormalizing the schema to accommodate performance requirements. That is dictated by the limitations of the physical technology, not the problem space.


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H. S. Lahman
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Relevant Pages

  • Re: chooses not to generate code at all
    ... reason to employ queries if one were not accessing RDB persistence through such infrastructures. ... I am not sure about your definition of DB and business transactions. ... Nor does one need a DBMS to handle persistence in transaction processing. ...
    (comp.object)
  • Re: SQL
    ... > SQL is not limited to persistence. ... I suppose that you are talking about your usage of SQL. ... Because you have created a new definition of the term RDM, ... Are you saying that the RDM is based on basic set theory or that the ...
    (comp.object)
  • Re: SQL
    ... RDM is nothing more than basic set theory? ... While Codd was the first to provide a formal and consistent view of the RDM, the RDM itself has been greatly expanded over the years beyond the RDB view. ... persistence in a computing environment so he expressed the rules in terms of embedded identity attributes. ... Class Models in most standard OOA/D books ...
    (comp.object)