Edit File: dpl_delete.html
<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!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"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>Deleting Entity Objects</title> <link rel="stylesheet" href="gettingStarted.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.62.4" /> <link rel="home" href="index.html" title="Getting Started with Berkeley DB" /> <link rel="up" href="persist_access.html" title="Chapter 5. Saving and Retrieving Objects" /> <link rel="previous" href="dpl_entityjoin.html" title="Join Cursors" /> <link rel="next" href="dpl_replace.html" title="Replacing Entity Objects" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">Deleting Entity Objects</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="dpl_entityjoin.html">Prev</a> </td> <th width="60%" align="center">Chapter 5. Saving and Retrieving Objects</th> <td width="20%" align="right"> <a accesskey="n" href="dpl_replace.html">Next</a></td> </tr> </table> <hr /> </div> <div class="sect1" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h2 class="title" style="clear: both"><a id="dpl_delete"></a>Deleting Entity Objects</h2> </div> </div> <div></div> </div> <p> The simplest way to remove an object from your entity store is to delete it by its primary index. For example, using the <tt class="classname">SimpleDA</tt> class that we created earlier in this document (see <a href="simpleda.html">SimpleDA.class</a>), you can delete the <tt class="classname">SimpleEntityClass</tt> object with a primary key of <tt class="literal">keyone</tt> as follows: </p> <pre class="programlisting">sda.pIdx.delete("keyone");</pre> <p> You can also delete objects by their secondary keys. When you do this, all objects related to the secondary key are deleted, unless the key is a foreign object. </p> <p> For example, the following deletes all <tt class="classname">SimpleEntityClass</tt> with a secondary key of <tt class="literal">skeyone</tt>: </p> <pre class="programlisting">sda.sIdx.delete("skeyone");</pre> <p> Finally, if you are indexing by foreign key, then the results of deleting the key is determined by the foreign key constraint that you have set for the index. See <a href="dplindexcreate.html#foreignkey">Foreign Key Constraints</a> for more information. </p> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="dpl_entityjoin.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="persist_access.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="dpl_replace.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">Join Cursors </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> Replacing Entity Objects</td> </tr> </table> </div> </body> </html>
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