Re: The same simple question to relational theorist (with video now).

On 30 avr, 20:03, Erwin <e.sm..._at_myonline.be> wrote:
> Op zaterdag 20 april 2013 21:57:19 UTC+2 schreef Evgeniy Grigoriev het volgende:
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> > суббота, 20 апреля 2013 г., 14:45:04 UTC+4 пользователь Eric написал:
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> > Hi Eric.
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> > Thank you! Also I don't want to think about how data is mapped (in both direction!) between realtional representation and object-oriented description.
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> > >I doubt it, because such mappings are an
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> > > unresolved and probably unresolvable problem.
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> > LOL. Eric, just look my video. I'm sure you will forsed to take these words back. I claim I solve the problem. Look my video and try to object.
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> Just watched some 25 mins of the video.
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> A few wild thoughts, not claiming I understand much of it.
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> The query results in your examples often show empty cells.  If their contents are something like NULL, then no, your system can almost by definition not be relational.
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> The system seems to be based on hierarchies of classes.  That makes me wonder about situations where there are self-references (boss of employee3 is employee2, boss of employee2 is employee7, ...) and transitive closures in the processing.
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> I'm wondering how transactions/commit/rollback fit into the system.  If there is "autocommit" upon each NEW GOODS() executed, then I wonder about the situations that require SQL users to switch over to deferred constraint checking.  (And if there is no possibility to declare constraints, then no, what you've created is not worth being called a DBMS.  But I rather doubt this is the case.)
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> You also use the term "inheritance" in connection with your classes, but it is unclear to me what "inheritance" really means here, or how it could be useful to me as a user of this system.

Inheritance is a mean not an end. Defining the end by the mean is a OO mindset favorite lost cause. Received on Sun May 05 2013 - 20:22:16 CEST