Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!news.albasani.net!.POSTED!not-for-mail From: Lew Newsgroups: comp.lang.java.programmer Subject: Re: ORM or JDBC? Date: Sat, 02 Apr 2011 10:25:03 -0400 Organization: albasani.net Lines: 21 Message-ID: References: <0c5037ee-f217-487c-9760-affd4bb6f181@n10g2000yqf.googlegroups.com> <4d8afdfe$0$41117$e4fe514c@news.xs4all.nl> <4d8ca45b$0$65870$e4fe514c@news.xs4all.nl> <4d8d53b1$0$23765$14726298@news.sunsite.dk> <4d90373e$0$81476$e4fe514c@news.xs4all.nl> <7rudncLSMpvB0A3QnZ2dnUVZ876dnZ2d@telenor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: news.albasani.net 6iWfk7fy/3F3YZIFfsqrJuHwOVKJFhFQ50I8w1FYIbCh1PCRoxKUPnoDNa0wQ/AH4E1KWddYQR7hjm8NhFGZLw== NNTP-Posting-Date: Sat, 2 Apr 2011 14:25:01 +0000 (UTC) Injection-Info: news.albasani.net; logging-data="PH38wF1I0TAcZKC3XFHobC/jnsgx+Jfs2I3YX+MvAqzMMDjU7+0fzWbnc+s0kxv5mBP1w+PIkYdVL6FDZYu1WfJEbVg0R76ukPlg86LGBEE+PXip6bRCuXT513z50il7"; mail-complaints-to="abuse@albasani.net" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.14) Gecko/20110223 Thunderbird/3.1.8 In-Reply-To: Cancel-Lock: sha1:/zdQWbWlTrXoGyWJPEq+I+BVQz8= Xref: x330-a1.tempe.blueboxinc.net comp.lang.java.programmer:2750 Arved Sandstrom wrote: > There is no super-distinct boundary, no. But there is a boundary > nonetheless. In the conceptual (semantic) model when we are thinking > about Person, we'll have a notion of Person identity - what attributes > of Person make them unique - but at this level that uniqueness could be > opaquely described as PersonID of no particular datatype, and we then go > on to discuss other attributes of Person that are necessary for the > business problem. Similarly, when thinking at this conceptual level > about LifeEvent, we might simply say that each LifeEvent instance will > point at a Person using the PersonId value. To this excellent taxonomy I would add only that the conceptual "PersonID" would identify the natural, or innate identifying data, one might say the "primary key". That's not correct at this level, though - what we're aiming for are the attributes that determine entity identity within the semantic model. A surrogate key, such as an integer-valued ID that perhaps is from a sequence, is something introduced in the physical model. -- Lew