1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
|
<html xmlns:MSHelp="http://msdn.microsoft.com/mshelp" xmlns:mshelp="http://msdn.microsoft.com/mshelp" xmlns:ddue="http://ddue.schemas.microsoft.com/authoring/2003/5" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:msxsl="urn:schemas-microsoft-com:xslt"><head><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8" /><META NAME="save" CONTENT="history" /><title>Join Method </title><link rel="stylesheet" type="text/css" href="../styles/presentation.css" /><link rel="stylesheet" type="text/css" href="ms-help://Hx/HxRuntime/HxLink.css" /><script type="text/javascript" src="../scripts/EventUtilities.js"> </script><script type="text/javascript" src="../scripts/SplitScreen.js"> </script><script type="text/javascript" src="../scripts/Dropdown.js"> </script><script type="text/javascript" src="../scripts/script_manifold.js"> </script><script type="text/javascript" src="../scripts/script_feedBack.js"> </script><script type="text/javascript" src="../scripts/CheckboxMenu.js"> </script><script type="text/javascript" src="../scripts/CommonUtilities.js"> </script><meta name="container" content="BerkeleyDB" /><meta name="file" content="M_BerkeleyDB_Database_Join" /><meta name="guid" content="M_BerkeleyDB_Database_Join" /><xml><MSHelp:Attr Name="AssetID" Value="M:BerkeleyDB.Database.Join(BerkeleyDB.SecondaryCursor[],System.Boolean)" /><MSHelp:TOCTitle Title="Join Method " /><MSHelp:RLTitle Title="Database.Join Method (BerkeleyDB)" /><MSHelp:Keyword Index="A" Term="M:BerkeleyDB.Database.Join(BerkeleyDB.SecondaryCursor[],System.Boolean)" /><MSHelp:Keyword Index="A" Term="frlrfBerkeleyDBDatabaseClassJoinTopic" /><MSHelp:Keyword Index="K" Term="Join method" /><MSHelp:Keyword Index="K" Term="Database.Join method" /><MSHelp:Keyword Index="F" Term="Join" /><MSHelp:Keyword Index="F" Term="Database.Join" /><MSHelp:Keyword Index="F" Term="BerkeleyDB.Database.Join" /><MSHelp:Attr Name="APIType" Value="Managed" /><MSHelp:Attr Name="APILocation" Value="libdb_dotnet53.dll" /><MSHelp:Attr Name="APIName" Value="BerkeleyDB.Database.Join" /><MSHelp:Attr Name="DevLang" Value="CSharp" /><MSHelp:Attr Name="DevLang" Value="VB" /><MSHelp:Attr Name="DevLang" Value="C++" /><MSHelp:Attr Name="Locale" Value="en-us" /><MSHelp:Attr Name="TopicType" Value="kbSyntax" /><MSHelp:Attr Name="TopicType" Value="apiref" /><MSHelp:Attr Name="Abstract" Value="Create a specialized join cursor for use in performing equality or natural joins on secondary indices." /><MSHelp:Attr Name="AssemblyVersion" Value="5.3.28.0" /></xml></head><body><input type="hidden" id="userDataCache" class="userDataStyle" /><input type="hidden" id="hiddenScrollOffset" /><img id="collapseImage" style="display:none; height:0; width:0;" src="../icons/collapse_all.gif" title="Collapse image" /><img id="expandImage" style="display:none; height:0; width:0;" src="../icons/expand_all.gif" title="Expand Image" /><img id="collapseAllImage" style="display:none; height:0; width:0;" src="../icons/collapse_all.gif" /><img id="expandAllImage" style="display:none; height:0; width:0;" src="../icons/expand_all.gif" /><img id="dropDownImage" style="display:none; height:0; width:0;" src="../icons/dropdown.gif" /><img id="dropDownHoverImage" style="display:none; height:0; width:0;" src="../icons/dropdownHover.gif" /><img id="copyImage" style="display:none; height:0; width:0;" src="../icons/copycode.gif" title="Copy image" /><img id="copyHoverImage" style="display:none; height:0; width:0;" src="../icons/copycodeHighlight.gif" title="CopyHover image" /><div id="header"><table id="topTable" cellspacing="0" cellpadding="0"><tr><td><span onclick="ExpandCollapseAll(toggleAllImage)" style="cursor:default;" onkeypress="ExpandCollapseAll_CheckKey(toggleAllImage, event)" tabindex="0"><img ID="toggleAllImage" class="toggleAll" src="../icons/collapse_all.gif" /> <label id="collapseAllLabel" for="toggleAllImage" style="display: none;">Collapse All</label><label id="expandAllLabel" for="toggleAllImage" style="display: none;">Expand All</label> </span><span> </span><span id="devlangsDropdown" class="filter" tabindex="0"><img id="devlangsDropdownImage" src="../icons/dropdown.gif" /> <label id="devlangsMenuAllLabel" for="devlangsDropdownImage" style="display: none;"><nobr>Code: All </nobr></label><label id="devlangsMenuMultipleLabel" for="devlangsDropdownImage" style="display: none;"><nobr>Code: Multiple </nobr></label><label id="devlangsMenuCSharpLabel" for="devlangsDropdownImage" style="display: none;"><nobr>Code: C# </nobr></label><label id="devlangsMenuVisualBasicLabel" for="devlangsDropdownImage" style="display: none;"><nobr>Code: Visual Basic </nobr></label><label id="devlangsMenuManagedCPlusPlusLabel" for="devlangsDropdownImage" style="display: none;"><nobr>Code: Visual C++ </nobr></label></span></td></tr></table><div id="devlangsMenu"><input id="CSharpCheckbox" type="checkbox" data="CSharp,cs,'persist'" value="on" onClick="SetLanguage(this)" /><label class="checkboxLabel" for="CSharpCheckbox">C#</label><br /><input id="VisualBasicCheckbox" type="checkbox" data="VisualBasic,vb,'persist'" value="on" onClick="SetLanguage(this)" /><label class="checkboxLabel" for="VisualBasicCheckbox">Visual Basic</label><br /><input id="ManagedCPlusPlusCheckbox" type="checkbox" data="ManagedCPlusPlus,cpp,'persist'" value="on" onClick="SetLanguage(this)" /><label class="checkboxLabel" for="ManagedCPlusPlusCheckbox">Visual C++</label><br /></div><table id="bottomTable" cellpadding="0" cellspacing="0"><tr id="headerTableRow1"><td align="left"><span id="runningHeaderText">Berkeley DB .NET API Documentation</span></td></tr><tr id="headerTableRow2"><td align="left"><span id="nsrTitle">Database<span class="languageSpecificText"><span class="cs">.</span><span class="vb">.</span><span class="cpp">::</span><span class="nu">.</span></span>Join Method </span></td></tr><tr id="headerTableRow3"><td align="left"><a href="T_BerkeleyDB_Database.htm">Database Class</a> <a href="#seeAlsoToggle" onclick="OpenSection(seeAlsoToggle)">See Also</a>
<span id="headfeedbackarea" class="feedbackhead">
<a href="javascript:SubmitFeedback('','Berkeley DB .NET API Documentation','','','','%0\dYour%20feedback%20is%20used%20to%20improve%20the%20documentation%20and%20the%20product.%20Your%20e-mail%20address%20will%20not%20be%20used%20for%20any%20other%20purpose%20and%20is%20disposed%20of%20after%20the%20issue%20you%20report%20is%20resolved.%20%20While%20working%20to%20resolve%20the%20issue%20that%20you%20report,%20you%20may%20be%20contacted%20via%20e-mail%20to%20get%20further%20details%20or%20clarification%20on%20the%20feedback%20you%20sent.%20After%20the%20issue%20you%20report%20has%20been%20addressed,%20you%20may%20receive%20an%20e-mail%20to%20let%20you%20know%20that%20your%20feedback%20has%20been%20addressed.%0\A%0\d','Customer%20Feedback');">
Send Feedback
</a>
</span>
</td></tr></table><table id="gradientTable"><tr><td class="nsrBottom" background="../icons/gradient.gif" /></tr></table></div><div id="mainSection"><div id="mainBody"><div id="allHistory" class="saveHistory" onsave="saveAll()" onload="loadAll()" /><span style="color: DarkGray"> </span><div class="summary">
Create a specialized join cursor for use in performing equality or
natural joins on secondary indices.
</div><p />
<b>Namespace:</b>
<a href="N_BerkeleyDB.htm">BerkeleyDB</a><br />
<b>Assembly:</b>
<span sdata="assembly">libdb_dotnet53</span> (in libdb_dotnet53.dll) Version: 5.3.28.0<h1 class="heading"><span onclick="ExpandCollapse(syntaxToggle)" style="cursor:default;" onkeypress="ExpandCollapse_CheckKey(syntaxToggle, event)" tabindex="0"><img id="syntaxToggle" class="toggle" name="toggleSwitch" src="../icons/collapse_all.gif" />Syntax</span></h1><div id="syntaxSection" class="section" name="collapseableSection" style=""><div id="syntaxCodeBlocks" class="code"><span codeLanguage="CSharp"><table><tr><th>C#</th></tr><tr><td><pre xml:space="preserve"><span class="keyword">public</span> <a href="T_BerkeleyDB_JoinCursor.htm">JoinCursor</a> <span class="identifier">Join</span>(
<a href="T_BerkeleyDB_SecondaryCursor.htm">SecondaryCursor</a>[] <span class="parameter">lst</span>,
<a href="http://msdn2.microsoft.com/en-us/library/a28wyd50" target="_blank">bool</a> <span class="parameter">sortCursors</span>
)</pre></td></tr></table></span><span codeLanguage="VisualBasicDeclaration"><table><tr><th>Visual Basic (Declaration)</th></tr><tr><td><pre xml:space="preserve"><span class="keyword">Public</span> <span class="keyword">Function</span> <span class="identifier">Join</span> ( _
<span class="parameter">lst</span> <span class="keyword">As</span> <a href="T_BerkeleyDB_SecondaryCursor.htm">SecondaryCursor</a>(), _
<span class="parameter">sortCursors</span> <span class="keyword">As</span> <a href="http://msdn2.microsoft.com/en-us/library/a28wyd50" target="_blank">Boolean</a> _
) <span class="keyword">As</span> <a href="T_BerkeleyDB_JoinCursor.htm">JoinCursor</a></pre></td></tr></table></span><span codeLanguage="ManagedCPlusPlus"><table><tr><th>Visual C++</th></tr><tr><td><pre xml:space="preserve"><span class="keyword">public</span>:
<a href="T_BerkeleyDB_JoinCursor.htm">JoinCursor</a>^ <span class="identifier">Join</span>(
<span class="keyword">array</span><<a href="T_BerkeleyDB_SecondaryCursor.htm">SecondaryCursor</a>^>^ <span class="parameter">lst</span>,
<a href="http://msdn2.microsoft.com/en-us/library/a28wyd50" target="_blank">bool</a> <span class="parameter">sortCursors</span>
)</pre></td></tr></table></span></div><div id="parameters"><h4 class="subHeading">Parameters</h4><dl paramName="lst"><dt><span class="parameter">lst</span></dt><dd>Type: <span class="languageSpecificText"><span class="cpp">array<</span></span>
<a href="T_BerkeleyDB_SecondaryCursor.htm">BerkeleyDB<span class="languageSpecificText"><span class="cs">.</span><span class="vb">.</span><span class="cpp">::</span><span class="nu">.</span></span>SecondaryCursor</a>
<span class="languageSpecificText"><span class="cpp">></span><span class="cs">[]</span><span class="vb">()</span><span class="nu">[]</span></span><br />
An array of SecondaryCursors. Each cursor must have been initialized
to refer to the key on which the underlying database should be
joined.
</dd></dl><dl paramName="sortCursors"><dt><span class="parameter">sortCursors</span></dt><dd>Type: <a href="http://msdn2.microsoft.com/en-us/library/a28wyd50" target="_blank">System<span class="languageSpecificText"><span class="cs">.</span><span class="vb">.</span><span class="cpp">::</span><span class="nu">.</span></span>Boolean</a><br />
If true, sort the cursors from the one that refers to the least
number of data items to the one that refers to the most. If the
data are structured so that cursors with many data items also share
many common elements, higher performance will result from listing
those cursors before cursors with fewer data items; that is, a sort
order other than the default. A setting of false permits
applications to perform join optimization prior to calling Join.
</dd></dl></div><h4 class="subHeading">Return Value</h4>
A specialized join cursor for use in performing equality or natural
joins on secondary indices.
</div><h1 class="heading"><span onclick="ExpandCollapse(remarksToggle)" style="cursor:default;" onkeypress="ExpandCollapse_CheckKey(remarksToggle, event)" tabindex="0"><img id="remarksToggle" class="toggle" name="toggleSwitch" src="../icons/collapse_all.gif" />Remarks</span></h1><div id="remarksSection" class="section" name="collapseableSection" style="">
<p>
Once the cursors have been passed as part of <span class="parameter">lst</span>,
they should not be accessed or modified until the newly created
<a href="T_BerkeleyDB_JoinCursor.htm">JoinCursor</a>has been closed, or else inconsistent
results may be returned.
</p>
<p>
Joined values are retrieved by doing a sequential iteration over the
first cursor in <span class="parameter">lst</span>, and a nested iteration over
each secondary cursor in the order they are specified in the
curslist parameter. This requires database traversals to search for
the current datum in all the cursors after the first. For this
reason, the best join performance normally results from sorting the
cursors from the one that refers to the least number of data items
to the one that refers to the most.
</p>
</div><h1 class="heading"><span onclick="ExpandCollapse(seeAlsoToggle)" style="cursor:default;" onkeypress="ExpandCollapse_CheckKey(seeAlsoToggle, event)" tabindex="0"><img id="seeAlsoToggle" class="toggle" name="toggleSwitch" src="../icons/collapse_all.gif" />See Also</span></h1><div id="seeAlsoSection" class="section" name="collapseableSection" style=""><div class="seeAlsoStyle"><a href="T_BerkeleyDB_Database.htm">Database Class</a></div><div class="seeAlsoStyle"><a href="N_BerkeleyDB.htm">BerkeleyDB Namespace</a></div></div></div><div id="footer"><div class="footerLine"><img width="100%" height="3px" src="../icons/footer.gif" title="Footer image" /></div><A NAME="feedback"></A><span id="fb" class="feedbackcss"> </span>
Report Feedback on this item in the Oracle Technology Network Forum <p />Copyright (c) 2008, 2013 Oracle. All rights reserved.</div></div></body></html>
|