Critique of Robert C. Martin's "Agile Principles, Patterns, and Practices"
in [OOP]
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From: Dmitry A. Kazakov on 29 Jan 2007 09:14 On 29 Jan 2007 04:31:40 -0800, frebe73(a)gmail.com wrote: >>> The relational model makes a distinction between logical an physical >>> data structures. Relations are a logical data structure. B-trees or kd- >>> trees are physical data structures. The logical and physical data >>> structures are independent of each other. A database which provides >>> relations, may still use any kind of physical structures. >> I see. A poster with a car is logical structure of that car. The car in the >> garage is the physical structure of. Are are selling me posters? > > Please read http://www.inconcept.com/JCM/May2002/pascal.html and you > have a deeper explaination about the difference between logical and > physical levels. At http://www.acm.org/classics/nov95/s1p2p2.html, you > can read what Dr Codd have to say about separating the choice of index > from the application (separation of concerns). I am impressed, bright colors, glossy paper, great. Now what about the car? Show me the data structure and the code for f. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de
From: frebe73 on 29 Jan 2007 09:41 > >>> The relational model makes a distinction between logical an physical > >>> data structures. Relations are a logical data structure. B-trees or kd- > >>> trees are physical data structures. The logical and physical data > >>> structures are independent of each other. A database which provides > >>> relations, may still use any kind of physical structures. > >> I see. A poster with a car is logical structure of that car. The car in the > >> garage is the physical structure of. Are are selling me posters? > > > Please readhttp://www.inconcept.com/JCM/May2002/pascal.htmland you > > have a deeper explaination about the difference between logical and > > physical levels. Athttp://www.acm.org/classics/nov95/s1p2p2.html, you > > can read what Dr Codd have to say about separating the choice of index > > from the application (separation of concerns).I am impressed, bright colors, glossy paper, great. > Now what about the car? > Show me the data structure and the code for f. If you think you will get an index and query optimizer implementation, I can tell you that this is not going to happen. But I can recommend to start reading about Oracle Spatial http://www.oracle.com/technology/products/spatial/index.html. Fredrik Bertilsson http://mybase.sf.net
From: Dmitry A. Kazakov on 29 Jan 2007 12:44 On 29 Jan 2007 06:41:04 -0800, frebe73(a)gmail.com wrote: >>>>> The relational model makes a distinction between logical an physical >>>>> data structures. Relations are a logical data structure. B-trees or kd- >>>>> trees are physical data structures. The logical and physical data >>>>> structures are independent of each other. A database which provides >>>>> relations, may still use any kind of physical structures. >>>> I see. A poster with a car is logical structure of that car. The car in the >>>> garage is the physical structure of. Are are selling me posters? >> >>> Please readhttp://www.inconcept.com/JCM/May2002/pascal.htmland you >>> have a deeper explaination about the difference between logical and >>> physical levels. Athttp://www.acm.org/classics/nov95/s1p2p2.html, you >>> can read what Dr Codd have to say about separating the choice of index >>> from the application (separation of concerns).I am impressed, bright colors, glossy paper, great. >> Now what about the car? >> Show me the data structure and the code for f. > > If you think you will get an index and query optimizer implementation, > I can tell you that this is not going to happen. As we rushing to full agreement, maybe, the last final question. Is it so that just you cannot solve the problem, or nobody can? -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de
From: frebe73 on 29 Jan 2007 14:23 > > If you think you will get an index and query optimizer implementation, > > I can tell you that this is not going to happen. > > As we rushing to full agreement, maybe, the last final question. Is it so > that just you cannot solve the problem, or nobody can? Are you totally ignorant about spatial databases? Do you claim that it doesn't exist any database that makes it possible to model spatial data as relations and still make it possible to have acceptable performance? Just google for "spatial databases" and you will find that there are pleny of solutions in the area. Even MySQL has support for index-types specialized for spatial queries. Below you can find some interesting links in the area. http://www.profc.udec.cl/~gabriel/tutoriales/giswb/vol1/cp4/cp4-5.htm http://www.informatik.fernuni-hagen.de/import/pi4/papers/ IntroSpatialDBMS.pdf http://www.opengeospatial.org/standards/sfs http://dev.mysql.com/doc/refman/5.0/en/optimizing-spatial- analysis.html Fredrik Bertilsson http://mybase.sf.net
From: Dmitry A. Kazakov on 29 Jan 2007 14:38
On 29 Jan 2007 11:23:40 -0800, frebe73(a)gmail.com wrote: >>> If you think you will get an index and query optimizer implementation, >>> I can tell you that this is not going to happen. >> >> As we rushing to full agreement, maybe, the last final question. Is it so >> that just you cannot solve the problem, or nobody can? > > Are you totally ignorant about spatial databases? No, I am of any "relational data structure" (RDS) for the problem described. Your references to some software products are irrelevant as long you cannot assert that they solve the problem using such an RDS. In case they do, please, don't hesitate to present it us. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de |