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Object Relation Mapping (ORM)
Another technical term? Yes - this one is a formal name for how you convert a database into Objects - applicable to any OO language (Perl, Python, PHP, Java ...) Let's reduce it to basics. * SQL Tables become object classes * Table rows each become individual objects * Individual columns become attributes. OK - perhaps you've been doing it for years .... I know I have, though not so formalised. It's nice to have a buzzword now to impress people with! But there's more to it than that. By writing code to formalise the conversion of data held in databases to objects, you can add a layer of abstraction and move the need to write SQL code within your application our to a separate module - very possibly a module that's already been written and placed on the CPAN or in the Cheeseshop or PEAR. In Perl, there have been a number of ORM modules placed on the CPAN; the current "flavour of the month" is DBIx::Class. A year or two back, it was Class::DBI, which you'll still find in use on some legacy applications. Both DBIx::Class and Class::DBI rely on Tim Bunce's DBI module internally, so they can be used with the same wide variety of databases that DBI/DBD supports. When you map a table onto a class, you'll note that your code repeats the definition of the column names in the Perl code (or Perl configuration file if you're being really good). But the programming axiom is "don't repeat anything" and if you're feeling REALLY clever, you can use DBIx::Class::Schema::Loader to pick it up from the database - as the cost of a little inefficiency in that the extra database enquiry is made every time you run your Perl. And THAT inefficiency can be prevented with dump_to_dir. (written 2007-06-09, updated 2007-06-12) Associated topics are indexed under G997 - Well House Consultants - Newsletter Lead Articles[3202] Telling you something about us in just one line - (2011-03-15) [2743] Public Open Source Training Courses running this summer and autumn in Melksham - (2010-04-27) [2538] Open Source Training Centre and Courses for 2010 - (2009-12-16) [2425] Weekend and Christmas Promotion - Well House Manor Hotel, Melksham - (2009-09-26) [2370] C++, Python, and other training - do we use an IDE - (2009-08-21) [2253] Walks in and around Melksham, Wiltshire - (2009-06-21) [2119] Make your business a DESTINATION business - (2009-04-05) [2052] How was my web site compromised? - (2009-02-24) [1912] Book now for 2009 - (2008-11-29) [1819] Calling base class constructors - (2008-10-03) [1754] Upgrade from PHP 4 to PHP 5 - the TRY issue - (2008-08-15) [1663] Python in an afternoon - a lecture for experienced programmers - (2008-06-01) [1600] Cambidge - Tcl, Expect and Perl courses - (2008-04-04) [1545] Letting new visitors know we provide training courses - (2008-02-19) [1488] New trainee laptop fleet for our Open Source courses - (2007-12-30) [1386] New software product for warmblooded programmers - (2007-10-10) [1318] Well House Manor - feature comparison against the old place! - (2007-08-24) [1136] Buffering output - why it is done and issues raised in Tcl, Perl, Python and PHP - (2007-04-06) [1065] Graham Ellis - an Introduction - (2007-02-05) [1000] One Thousand Posts and still going strong - (2006-12-18) Q908 - Object Orientation and General technical topics - Object Orientation: Design Patterns [4096] Perl design patterns example - (2013-05-20) [4021] Spike solution, refactored and reusable, Python - Example - (2013-02-28) [3843] Caching Design Patterns - (2012-08-20) [3810] Reading files, and using factories to create vectors of objects from the data in C++ - (2012-07-21) [3716] Learning C++ - a design pattern for your first class - (2012-05-02) [3608] Design Patterns - what are they? 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Some other Articles
Some progress on the train campaignMelksham businesses - networking together Melksham Art Cafe Perl - functions for directory handling Object Relation Mapping (ORM) Asda opening large new store in Melksham Perl, the substitute operator s Bathtubs and pecking birds for loop - how it works (Perl, PHP, Java, C, etc) Judging the quality of contributed Perl code |
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Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82 at 50 posts per pageThis is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.
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