<?xml version="1.0" encoding='utf-8'?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml">
<wml>
<card id="card1" title="Federated database system - Page 17 - Wikipedia">
<p>
<a accesskey="1" href="page.php?w=Federated_database_system&amp;p=16">1.Previous</a><br />
<a accesskey="3" href="page.php?w=Federated_database_system&amp;p=18">3.Next</a>
</p>
<p>such heterogeneities before integrating the component DB schemas.</p>

<p><big> Schema matching, schema mapping </big></p>
<p>Dealing with incompatible data types or query syntax is not the only obstacle to a concrete implementation of an FDBS. In systems that are not planned top-down, a generic problem lies in matching <a href="page.php?w=semantic_equivalence">semantically equivalent</a>, but differently named parts from different <a href="page.php?w=logical_schema">schemas</a> (=data models) (tables, attributes). A pairwise mapping between n attributes</p><p>
<a accesskey="1" href="page.php?w=Federated_database_system&amp;p=16">1.Previous</a><br />
<a accesskey="3" href="page.php?w=Federated_database_system&amp;p=18">3.Next</a>
</p>

<do type="prev" label="Search">
        <go href="search.wml"/>
</do>

</card>
</wml>
