<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Hi Julien,<div><br></div><div>Thanks for your question. It really depends on what you are trying to publish. We can add extensions of course, but without knowing the specifics it is difficult to comment.</div><div><br></div><div>However, a “specimen, event, location” DB model would typically map to an Occurrence core with no extensions required - this is the most common use case of Darwin Core and the IPT. An Occurrence core is basically a denormalized view of the data.</div><div><br></div><div>If I were the data manager, I would probably consider that I was publishing a “DwC Occurrence view” of my more complex model and as such would keep a view in the database along the lines of:</div><div><br></div><div>CREATE VIEW view_dwc_occurrence AS</div><div>SELECT</div><div> specimen.bar_code AS occurrenceID,</div><div> specimen.name AS scientificName,</div><div> location.latitude AS decimalLatitude,</div><div> location.longitude AS decimalLongitude,</div><div> event.year AS year</div><div>FROM </div><div> specimen </div><div> JOIN event ON … </div><div> JOIN location ON …</div><div>WHERE</div><div> <insert any conditions for record inclusion, such as non endangered etc></div><div><br></div><div>Then in my IPT I would simply do “SELECT * FROM view_dwc_occurrence”. Here you are flattening the normalised model into a denormalized DwC view of the data.</div><div><br></div><div>Maintaining a view in the database layer as opposed to a custom mapping in the IPT benefits you by:</div><div> i) catching issues early with database schema changes since the DB will likely stop you with an error</div><div> ii) offering an easy mapping of DB table field names, to DwC terms in a language I find very familiar (SQL)</div><div> iii) a super simple IPT mapping, as all columns will map automatically in the IPT since they are DwC recognised terms already</div><div><br></div><div>Does that help in any way? If not, could you please elaborate on the model and what you are trying to achieve and we’ll do all we can.</div><div><br></div><div>Thanks,</div><div>Tim</div><div><br></div><div> </div><div><br><div><div>On 14 Mar 2014, at 16:06, Julien Husson <<a href="mailto:biology.info@gmail.com">biology.info@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr"><div><div><div>Hi,<br><br></div><div>I use Dwc-A to feed my BD.<br></div><div><br></div>We know the limits of the Dwc star schema to represent a relationnal database.<br><br><span id="result_box" class="" lang="en">For example in the case of 1-n cardinality : specimen --- event/record --- location.<br>
</span><span id="result_box" class="" lang="en">If i understand the concept, I need to use </span><span id="result_box" class="" lang="en">the Darwin <b>Core</b> <b>Occurrence</b> <b>extension</b>, denormalize my relational model in a big raw model and transform / re-normalize this model to match with my DB model</span>.<br>
<br><span id="result_box" class="" lang="en"><span class="">In</span> <span class="">order to reduce cost<em>, </em>dev<em> </em>and<em> </em>optimize sql statement, it will be </span></span><span id="result_box" class="" lang="en"><span id="result_box" class="" lang="en"><span class="">grandly</span></span> appreciate to add custom extension. In this case, i can to be very close of my relational database model and avoid multiple step of dev.<br>
</span></div><span id="result_box" class="" lang="en"><span class=""></span></span></div><span id="result_box" class="" lang="en"><span class=""></span></span><div><div><br>I discovered this link but explanantion is now deprecated<br>
<a href="http://dag-endresen.blogspot.fr/2009/06/adding-extension-for-germplasm-to-gbif.html">http://dag-endresen.blogspot.fr/2009/06/adding-extension-for-germplasm-to-gbif.html</a><br><br></div><div>Thanks,<br><br></div>
<div>J.<br></div></div></div>
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