003 File Manager
Current Path:
/usr/local/share/doc/db5/gsg/CXX
usr
/
local
/
share
/
doc
/
db5
/
gsg
/
CXX
/
📁
..
📄
BerkeleyDB-Core-Cxx-GSG.pdf
(402.24 KB)
📄
CoreCursorUsage.html
(11.1 KB)
📄
CoreDBAdmin.html
(5.22 KB)
📄
CoreDbCXXUsage.html
(7 KB)
📄
CoreEnvUsage.html
(6.97 KB)
📄
Cursors.html
(5.93 KB)
📄
DBEntry.html
(6.46 KB)
📄
DBOpenFlags.html
(4.32 KB)
📄
DbCXXUsage.html
(20.83 KB)
📄
DeleteEntryWCursor.html
(3.69 KB)
📄
Positioning.html
(19.87 KB)
📄
PutEntryWCursor.html
(8.37 KB)
📄
ReplacingEntryWCursor.html
(4.94 KB)
📄
accessmethods.html
(12.5 KB)
📄
btree.html
(21.41 KB)
📄
cachesize.html
(4.56 KB)
📄
concepts.html
(8.63 KB)
📄
coreExceptions.html
(3.78 KB)
📄
coredbclose.html
(4.33 KB)
📄
coreindexusage.html
(22.31 KB)
📄
databaseLimits.html
(3.77 KB)
📄
databases.html
(6.07 KB)
📄
dbErrorReporting.html
(7.36 KB)
📄
dbconfig.html
(17.69 KB)
📄
environments.html
(6.31 KB)
📄
gettingStarted.css
(1.13 KB)
📄
gettingit.html
(3.45 KB)
📄
index.html
(16.66 KB)
📄
indexes.html
(12.17 KB)
📄
introduction.html
(9.77 KB)
📄
joins.html
(10.09 KB)
📄
keyCreator.html
(10.23 KB)
📄
moreinfo.html
(6.97 KB)
📄
preface.html
(6.36 KB)
📄
readSecondary.html
(4.95 KB)
📄
returns.html
(3.52 KB)
📄
secondaryCursor.html
(5.34 KB)
📄
secondaryDelete.html
(5.79 KB)
📄
usingDbt.html
(15.18 KB)
Editing: secondaryCursor.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>Using Cursors with Secondary Databases</title> <link rel="stylesheet" href="gettingStarted.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> <link rel="start" href="index.html" title="Getting Started with Berkeley DB" /> <link rel="up" href="indexes.html" title="Chapter 5. Secondary Databases" /> <link rel="prev" href="secondaryDelete.html" title="Deleting Secondary Database Records" /> <link rel="next" href="joins.html" title="Database Joins" /> </head> <body> <div xmlns="" class="navheader"> <div class="libver"> <p>Library Version 11.2.5.3</p> </div> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center"> <span xmlns="http://www.w3.org/1999/xhtml">Using Cursors with Secondary Databases</span> </th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="secondaryDelete.html">Prev</a> </td> <th width="60%" align="center">Chapter 5. Secondary Databases</th> <td width="20%" align="right"> <a accesskey="n" href="joins.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="secondaryCursor"></a> <span>Using Cursors with Secondary Databases</span> </h2> </div> </div> </div> <p> Just like cursors on a primary database, you can use <span>cursors on secondary databases</span> to iterate over the records in a secondary database. Like <span>cursors used with primary databases,</span> you can also use <span>cursors with secondary databases</span> to search for specific records in a database, to seek to the first or last record in the database, to get the next duplicate record, and so forth. For a complete description on cursors and their capabilities, see <a class="xref" href="Cursors.html" title="Chapter 4. Using Cursors">Using Cursors</a>. </p> <p> However, when you use <span>cursors with secondary databases:</span> </p> <div class="itemizedlist"> <ul type="disc"> <li> <p> Any data returned is the data contained on the primary database record referenced by the secondary record. </p> </li> <li> <p> You cannot use <code class="literal">DB_GET_BOTH</code> and related flags with <code class="methodname">Db::get()</code> and a secondary database. Instead, you must use <span><code class="methodname">Db::pget()</code>.</span> Also, in that case the primary and secondary key given on the call to <code class="methodname">Db::pget()</code> must match the secondary key and associated primary record key in order for that primary record to be returned as a result of the call. </p> </li> </ul> </div> <p> For example, suppose you are using the databases, classes, and key <span>extractors</span> described in <a class="xref" href="keyCreator.html" title="Implementing Key Extractors">Implementing Key <span>Extractors</span> </a>. Then the following searches for a person's name in the secondary database, and deletes all secondary and primary records that use that name. </p> <a id="cxx_index8"></a> <pre class="programlisting">#include <db_cxx.h> ... Db my_database(NULL, 0); Db my_index(NULL, 0); // Get a cursor on the secondary database Dbc *cursorp; my_index.cursor(NULL, &cursorp, 0); // Name to delete char *search_name = "John Doe"; // Instantiate Dbts as normal Dbt key(search_name, strlen(search_name) + 1); Dbt data; // Position the cursor while (cursorp->get(&key, &data, DB_SET) == 0) cursorp->del(0); </pre> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="secondaryDelete.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="indexes.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="joins.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">Deleting Secondary Database Records </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> Database Joins</td> </tr> </table> </div> </body> </html>
Upload File
Create Folder