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	<p>The schema makes extensive use of inheritance, which can be implemented in <a href="http://stackoverflow.com/questions/3579079/how-can-you-represent-inheritance-in-a-database#3579462" class="external">several ways</a>. The tables are shown in the ERD using <a href="http://stackoverflow.com/questions/3579079/how-can-you-represent-inheritance-in-a-database#3579462" class="external">class table inheritance</a> (option 3 in the link), which is considered the best practice for most database engines. However, <em>if and only if</em> <a href="http://www.postgresql.org/docs/9.1/static/ddl-inherit.html" class="external">PostgreSQL-style inheritance</a> is available, it's actually better to use <a href="http://stackoverflow.com/questions/3579079/how-can-you-represent-inheritance-in-a-database#3579462" class="external">concrete table inheritance</a> (option 2), which avoids both the need to insert into each superclass table separately, and the need to join to superclass tables when selecting<sup><a href="#fn1">1</a></sup>. When this is not available, you can also get these benefits via <a href="http://stackoverflow.com/questions/3579079/how-can-you-represent-inheritance-in-a-database#3579462" class="external">single table inheritance</a> (option 1, which is the denormalized, full_occurrence format) at the expense of not having separate tables for the separate subclasses.</p>

	<p id="fn1" class="footnote"><sup>1</sup> at the cost of slightly slower index scans when there is a large number of subclasses and rows are evenly distributed between them (because each subclass index needs to be scanned separately)</p>

	<p><a href="http://VegCore.vegpath.org/ERD/"><img src="http://vegpath.org/VegCore/ERD/VegCore.ERD.png" title="VegCore schema: click for hyperlinked version" alt="VegCore schema: click for hyperlinked version" /></a></p>

	<p><a href="#Source" class="wiki-page">Source</a><br /><a href="#Dataset" class="wiki-page">Dataset</a><br /><a href="#Record" class="wiki-page">Record</a><br /><a href="#Occurrence" class="wiki-page">Occurrence</a><br /><a href="#Method" class="wiki-page">Method</a><br /><a href="#Stratum" class="wiki-page">Stratum</a><br /><a href="#Project" class="wiki-page">Project</a><br /><a href="#Event" class="wiki-page">Event</a><br /><a href="#Coordinates" class="wiki-page">Coordinates</a><br /><a href="#Placename" class="wiki-page">Placename</a><br /><a href="#Geovalidation" class="wiki-page">Geovalidation</a><br /><a href="#Location" class="wiki-page">Location</a><br /><a href="#LocationObservation" class="wiki-page">LocationObservation</a><br /><a href="#Subplot" class="wiki-page">Subplot</a><br /><a href="#SubplotObservation" class="wiki-page">SubplotObservation</a><br /><a href="#SoilObservation" class="wiki-page">SoilObservation</a><br /><a href="#GeologicalContext" class="wiki-page">GeologicalContext</a><br /><a href="#Community" class="wiki-page">Community</a><br /><a href="#TaxonName" class="wiki-page">TaxonName</a><br /><a href="#TaxonConcept" class="wiki-page">TaxonConcept</a><br /><a href="#QualifiedTaxonName" class="wiki-page">QualifiedTaxonName</a><br /><a href="#MatchedTaxon" class="wiki-page">MatchedTaxon</a><br /><a href="#AcceptedTaxon" class="wiki-page">AcceptedTaxon</a><br /><a href="#TaxonOccurrence" class="wiki-page">TaxonOccurrence</a><br /><a href="#TaxonDetermination" class="wiki-page">TaxonDetermination</a><br /><a href="#OriginalTaxonDetermination" class="wiki-page">OriginalTaxonDetermination</a><br /><a href="#TaxonObservation" class="wiki-page">TaxonObservation</a><br /><a href="#AggregateObservation" class="wiki-page">AggregateObservation</a><br /><a href="#Individual" class="wiki-page">Individual</a><br /><a href="#IndividualObservation" class="wiki-page">IndividualObservation</a><br /><a href="#Stem" class="wiki-page">Stem</a><br /><a href="#StemObservation" class="wiki-page">StemObservation</a><br /><a href="#Collection" class="wiki-page">Collection</a><br /><a href="#Specimen" class="wiki-page">Specimen</a><br /><a href="#Voucher" class="wiki-page">Voucher</a><br /><a href="#Measurement" class="wiki-page">Measurement</a><br /><a href="#ResourceRelationship" class="wiki-page">ResourceRelationship</a></p>

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<h3  style="padding-left:4em;"><img src="_" style="padding: 0 0.3em 3pt 0.65em;font-weight: normal;" title="Synonym:" alt="Synonym:" /> <a href="#pubDate" class="wiki-page">pubDate</a> <img src="_" style="padding-left: 1em;font-size: small;font-weight: normal;" title="from" alt="from" /> <a href="http://vegbank.org/vegbank/views/dba_tabledescription_detail.jsp?view=detail&#38;wparam=reference&#38;entity=dba_tabledescription&#38;where=where_tablename#pubDate"><img src="_" style="font-size: small;" title="VegBank" alt="VegBank" /></a><a href="#pubDate" class="wiki-anchor">&para;</a></h3>

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<h1 ><a href="#Stratum" class="wiki-page">Stratum</a> <img src="_" style="padding-left: 1em;font-size: small;font-weight: normal;" title="from" alt="from" /> <a href="http://VegX.vegpath.org?stratum"><img src="_" style="font-size: small;" title="VegX" alt="VegX" /></a> <img src="_" style="font-size: small;" title="|" alt="|" /> <a href="http://VegBank.vegpath.org?stratumType"><img src="_" style="font-size: small;" title="VegBank" alt="VegBank" /></a><a href="#Stratum" class="wiki-anchor">&para;</a></h1>

	<p style="padding-left:3em;">a non-horizontal way of subdividing a plot</p>

	<a name="stratum__name"></a>

<h2  style="padding-left:2em;"><a href="#stratum__name" class="wiki-page">stratum__name</a> <img src="_" style="padding-left: 1em;font-size: small;font-weight: normal;" title="from" alt="from" /> <a href="http://VegX.vegpath.org?stratum.stratumName"><img src="_" style="font-size: small;" title="VegX" alt="VegX" /></a> <img src="_" style="font-size: small;" title="|" alt="|" /> <a href="http://VegBank.vegpath.org?stratumType.stratumName"><img src="_" style="font-size: small;" title="VegBank" alt="VegBank" /></a><a href="#stratum__name" class="wiki-anchor">&para;</a></h2>