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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <script src="./callback.js" type="text/javascript"></script> <noscript>Your browser does not support JavaScript. This help page requires JavaScript to render correctly.</noscript> </head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii" /> <meta http-equiv="Content-Style-Type" content="text/css" /> <meta http-equiv="Content-Script-Type" content="text/javascript" /> <meta name="generator" content="Oracle DARB XHTML Converter (Mode = ohj/ohw) - Version 5.1.1 Build 005" /> <meta name="date" content="2009-04-21T9:46:23Z" /> <meta name="robots" content="noarchive" /> <meta name="doctitle" content="About Schema Objects" /> <meta name="relnum" content="11g Release 2 (11.2)" /> <meta name="partnum" content="E10766-01" /> <link rel="copyright" href="./dcommon/html/cpyr.htm" title="Copyright" type="text/html" /> <link rel="stylesheet" href="./dcommon/css/blafdoc.css" title="Oracle BLAFDoc" type="text/css" /> <link rel="contents" href="toc.htm" title="Contents" type="text/html" /> <link rel="prev" href="tdddg_intro003.htm" title="Previous" type="text/html" /> <link rel="next" href="tdddg_intro005.htm" title="Next" type="text/html" /> <title>About Schema Objects</title> </head> <body> <div class="zz-skip-header"><a href="#BEGIN">Skip Headers</a></div> <table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%"> <col width="86%" /> <col width="*" /> <tr valign="bottom"> <td align="left"></td> <td align="center"><a href="tdddg_intro003.htm"><img width="24" height="24" src="./dcommon/gifs/leftnav.gif" alt="Previous" /><br /> <span class="icon">Previous</span></a> </td> <td align="center"><a href="tdddg_intro005.htm"><img width="24" height="24" src="./dcommon/gifs/rightnav.gif" alt="Next" /><br /> <span class="icon">Next</span></a></td> </tr> </table> <p><a id="CEGBCDFB" name="CEGBCDFB"></a><a id="TDDDG11200" name="TDDDG11200"></a></p> <div class="sect2"><!-- infolevel="all" infotype="General" --> <h1>About Schema Objects</h1> <a name="BEGIN" id="BEGIN"></a> <p>Every object in an Oracle Database belongs to only one schema, and has a unique name with that schema.</p> <p>Some of the objects that schemas can contain are:</p> <ul> <li> <p><span class="bold">Tables</span></p> <p>Tables are the basic units of data storage in Oracle Database. Tables hold all user-accessible data. Each table contains <span class="bold">rows</span> that represent individual data <span class="bold"><a id="sthref3" name="sthref3"></a><a id="sthref4" name="sthref4"></a>records</span>. Rows are composed of <a id="sthref5" name="sthref5"></a><span class="bold">columns</span> that represent the <span class="bold"><a id="sthref6" name="sthref6"></a>fields</span> of the records. For more information, see <a href="tdddg_objects003.htm#BABEBEJF">"Creating and Managing Tables"</a>.</p> </li> <li> <p><a id="sthref7" name="sthref7"></a><span class="bold">Indexes</span></p> <p>Indexes are optional objects that can improve the performance of data retrieval from tables. Indexes are created on one or more columns of a table, and are automatically maintained in the database. For more information, see <a href="tdddg_objects014.htm#BABHAGCH">"Managing Indexes"</a>.</p> </li> <li> <p><span class="bold">Views</span></p> <p>You can create a view that combines information from several different tables into a single presentation. A view can rely on information from both tables and other views. For more information, see <a href="tdddg_objects019.htm#BABEJDII">"Creating and Managing Views"</a>.</p> </li> <li> <p><span class="bold">Sequences</span></p> <p>When all records of a table must be distinct, you can use a sequence to generate a serial list of unique integers for numeric columns, each of which represents the ID of one record. For more information, see <a href="tdddg_objects025.htm#BABJICJI">"Creating and Managing Sequences"</a>.</p> </li> <li> <p><span class="bold">Synonyms</span></p> <p>Synonyms are aliases for schema objects. You can use synonyms for security and convenience; for example, to hide the ownership of an object or to simplify SQL statements. For more information, see <a href="tdddg_objects028.htm#BABCFIFI">"Creating and Managing Synonyms"</a>.</p> </li> <li> <p><span class="bold">Stored subprograms</span></p> <p>Stored subprograms (also called <span class="bold">schema-level subprograms</span>) are procedures and functions that are stored in the database. They can be invoked from client applications that access the database. For more information, see <a href="tdddg_subprograms.htm#CIHDFDJG">"Developing Stored Subprograms and Packages"</a>.</p> <p><a id="sthref8" name="sthref8"></a><span class="bold">Triggers</span> are stored subprograms that are automatically run by the database when specified events occur in a particular table or view. Triggers can restrict access to specific data, perform logging, or audit data. For more information, see <a href="tdddg_triggers.htm#BABIEDEF">"Using Triggers"</a>.</p> </li> <li> <p><span class="bold">Packages</span></p> <p>A package is a group of related subprograms, along with the explicit cursors and variables they use, stored in the database as a unit, for continued use. Like stored subprograms, packaged subprograms can be invoked from client applications that access the database. For more information, see <a href="tdddg_subprograms.htm#CIHDFDJG">"Developing Stored Subprograms and Packages"</a>.</p> </li> </ul> <p>Typically, the objects that an application uses belong to the same schema.</p> <div class="helpinfonotealso"> <h2>Related Topics</h2> <p><a href="javascript:open('http://www.oracle.com/pls/db112/lookup?id=CNCPT010','newWindow').focus()"><span class="italic">Oracle Database Concepts</span></a></p> <p><a href="tdddg_intro003.htm#CEGEBHHF">About Oracle Database</a></p> </div> </div> <!-- class="sect2" --> <!-- Start Footer --> <div class="footer"> <table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%"> <col width="86%" /> <col width="*" /> <tr> <td align="left"><span class="copyrightlogo">Copyright © 1996, 2009, Oracle and/or its affiliates. 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