http://wiki.karljones.com/index.php?action=history&feed=atom&title=Object-relational_impedance_mismatch 2026-10-23T14:23:04Z Revision history for this page on the wiki MediaWiki 1.24.2 http://wiki.karljones.com/index.php?title=Object-relational_impedance_mismatch&diff=17109&oldid=prev 2016-08-24T12:02:29Z

<p></p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 12:02, 24 August 2016</td> </tr><tr><td colspan="2" class="diff-lineno">Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>The '''object-relational impedance mismatch''' is a set of conceptual and technical difficulties that are often encountered when a [[relational database management system]] (RDBMS) is being served by an application program (or multiple application programs) written in an [[object-oriented programming]] language or style, particularly because objects or class definitions must be mapped to database tables defined by relational schemata.</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>The '''object-relational impedance mismatch''' is a set of conceptual and technical difficulties that are often encountered when a [[relational database management system]] (RDBMS) is being served by an application program (or multiple application programs) written in an [[object-oriented programming]] language or style, particularly because objects or class definitions must be mapped to database tables defined by relational schemata.</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The term object-relational impedance mismatch is derived from the electrical engineering term impedance matching.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The term object-relational impedance mismatch is derived from the <ins class="diffchange diffchange-inline">[[</ins>electrical engineering<ins class="diffchange diffchange-inline">]] </ins>term impedance matching<ins class="diffchange diffchange-inline">.</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>&#160;</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Fundamentally, objects (instances) reference one another and therefore form a graph in the mathematical sense (a network including loops and cycles). Relational schemas are, in contrast, tabular and based on the Relational algebra which defines linked heterogenous tuples (groupings of data fields into a &quot;row&quot; with different types for each field).</ins></div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>&#160;</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Converting linked tabular rows to graph structures is hard, and even described as the [http://blogs.tedneward.com/post/the-vietnam-of-computer-science/ Vietnam of Computer Science]</ins>.</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>== See also ==</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>== See also ==</div></td></tr> </table>

Karl Jones http://wiki.karljones.com/index.php?title=Object-relational_impedance_mismatch&diff=17105&oldid=prev 2016-08-24T03:09:03Z

<p>Created page with &quot;The &#039;&#039;&#039;object-relational impedance mismatch&#039;&#039;&#039; is a set of conceptual and technical difficulties that are often encountered when a <a href="/index.php/Relational_database_management_system" title="Relational database management system">relational database management system</a> (R...&quot;</p> <p><b>New page</b></p><div>The '''object-relational impedance mismatch''' is a set of conceptual and technical difficulties that are often encountered when a [[relational database management system]] (RDBMS) is being served by an application program (or multiple application programs) written in an [[object-oriented programming]] language or style, particularly because objects or class definitions must be mapped to database tables defined by relational schemata.<br /> <br /> The term object-relational impedance mismatch is derived from the electrical engineering term impedance matching.<br /> <br /> == See also ==<br /> <br /> * [[Object-oriented programming]]<br /> * [[Object-relational mapping]] - a programming technique for converting [[data (computing)]] between incompatible [[Type system|type systems]] in [[object-oriented programming]] languages.<br /> <br /> == External links ==<br /> <br /> * [https://en.wikipedia.org/wiki/Object-relational_impedance_mismatch Object-relational impedance mismatch] @ Wikipedia<br /> <br /> [[Category:Computer science]]</div>

Karl Jones