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| <org.eclipse.epf.uma:ArtifactDescription xmi:version="2.0" |
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| name="logical_data_model,_TI3JIBtsEdu_BZ3CL1I6hw" guid="-3fT4U_TQiQFAHZQp8_7GkQ" |
| changeDate="2007-07-17T15:45:41.742-0700" version="1.0.0"> |
| <mainDescription><a id="XE_logical_data_model" name="XE_logical_data_model"></a> 
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| <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt">
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| <span style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"><span
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| style="mso-bidi-font-size: 10.0pt; mso-bidi-font-family: Arial">From the point of view of an object-oriented developer
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| data modeling is conceptually similar to class modeling. With data modeling you identify entity types whereas with
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| class modeling you identify classes.&nbsp; Data attributes are assigned to entity types just as you would assign
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| attributes and operations to classes. Traditional data modeling is different from class modeling because it focuses
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| solely on data – class models allow you to explore both the behavior and data aspects of your domain, with a data model
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| you can only explore data issues.</span></span>
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| </p><br class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" />
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| <br />
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| <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt">
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| <span style="mso-bidi-font-size: 10.0pt; mso-bidi-font-family: Arial">We use UML simple class diagram to represent
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| a</span> <b><span style="mso-bidi-font-family: Arial">Logical Data Model</span></b> <span
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| style="mso-bidi-font-size: 10.0pt; mso-bidi-font-family: Arial">but&nbsp;by applying&nbsp;Agile's principle of multiple
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| models, it is possible to use other diagram.</span>
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| </p><br class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" />
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| <br />
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| <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt">
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| <b><span style="mso-bidi-font-family: Arial">Logical Data Models</span></b> <span
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| style="mso-bidi-font-size: 10.0pt; mso-bidi-font-family: Arial">are used to explore the domain concepts, and their
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| relationships, of&nbsp;the problem domain.&nbsp; This could be done for the scope of a single project or for&nbsp;the
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| entire enterprise.&nbsp; LDMs depict the logical entity types, typically referred to simply as entity types, the data
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| attributes describing those entities, and the relationships between the entities.&nbsp;</span>
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| </p><br class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" />
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| <br />
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| <p class="MsoNormal" style="MARGIN: 3pt 0cm">
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| <span style="mso-bidi-language: HE">A <b>Fact Model</b> represents structured business vocabulary with true statement
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| like: A customer places an order. The fact model looks like the Object Role Model described by Halpin (2001). When the
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| model starts to grow the notation become quickly invisible and no more helpful, so we do not encourage to follow the
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| notation.</span>
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| </p><br class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" />
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| <br />
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| <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt">
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| <b><span style="mso-bidi-font-size: 10.0pt; mso-bidi-font-family: Arial">A Fact Model should always include elementary
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| (atomic) fact type:</span></b>
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| </p>
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| <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt 18pt; TEXT-INDENT: -18pt">
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| <span style="FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt">•</span><span
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| style="FONT-SIZE: 7pt; FONT-FAMILY: 'Times New Roman'">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span>
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| <span style="mso-bidi-font-size: 10.0pt; mso-bidi-font-family: Arial">Noun:&nbsp; Customer, Order, Product</span>
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| </p>
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| <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt 18pt; TEXT-INDENT: -18pt">
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| <span style="FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 10.0pt">•</span><span
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| style="FONT-SIZE: 7pt; FONT-FAMILY: 'Times New Roman'">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span>
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| <span style="mso-bidi-font-size: 10.0pt; mso-bidi-font-family: Arial">Verb:&nbsp; places, briefs</span>
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| </p><br class="MsoNormal" style="MARGIN: 0cm 0cm 0pt 18pt; TEXT-INDENT: -18pt" />
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| <br />
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| <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt">
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| <span style="mso-bidi-font-size: 10.0pt; mso-bidi-font-family: Arial">We may use&nbsp;Object Role Models to explore the
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| domain with project stakeholders but later replace them with a more traditional artifact such as an LDM, a class
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| diagram, or even a PDM</span>
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| </p><br />
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| <br /></mainDescription> |
| <purpose>Data modeling is the act of exploring data-oriented structures.&nbsp; Like other modeling artifacts data models can be used
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| for a variety of purposes, from high-level conceptual models to physical data models.</purpose> |
| </org.eclipse.epf.uma:ArtifactDescription> |
