Adding upstream version 3.45.1.upstream/3.45.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-13 14:07:11 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-13 14:07:11 +0000
commit: 63847496f14c813a5d80efd5b7de0f1294ffe1e3 (patch)
tree: 01c7571c7c762ceee70638549a99834fdd7c411b /www/lang_indexedby.html
parent: Initial commit. (diff)
download: sqlite3-63847496f14c813a5d80efd5b7de0f1294ffe1e3.tar.xz
sqlite3-63847496f14c813a5d80efd5b7de0f1294ffe1e3.zip
1 files changed, 260 insertions, 0 deletions
diff --git a/www/lang_indexedby.html b/www/lang_indexedby.html
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+<!DOCTYPE html>
+<html><head>
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+<link href="sqlite.css" rel="stylesheet">
+<title>The INDEXED BY Clause</title>
+<!-- path= -->
+</head>
+<body>
+<div class=nosearch>
+<a href="index.html">
+<img class="logo" src="images/sqlite370_banner.gif" alt="SQLite" border="0">
+</a>
+<div><!-- IE hack to prevent disappearing logo --></div>
+<div class="tagline desktoponly">
+Small. Fast. Reliable.<br>Choose any three.
+</div>
+<div class="menu mainmenu">
+<ul>
+<li><a href="index.html">Home</a>
+<li class='mobileonly'><a href="javascript:void(0)" onclick='toggle_div("submenu")'>Menu</a>
+<li class='wideonly'><a href='about.html'>About</a>
+<li class='desktoponly'><a href="docs.html">Documentation</a>
+<li class='desktoponly'><a href="download.html">Download</a>
+<li class='wideonly'><a href='copyright.html'>License</a>
+<li class='desktoponly'><a href="support.html">Support</a>
+<li class='desktoponly'><a href="prosupport.html">Purchase</a>
+<li class='search' id='search_menubutton'>
+<a href="javascript:void(0)" onclick='toggle_search()'>Search</a>
+</ul>
+</div>
+<div class="menu submenu" id="submenu">
+<ul>
+<li><a href='about.html'>About</a>
+<li><a href='docs.html'>Documentation</a>
+<li><a href='download.html'>Download</a>
+<li><a href='support.html'>Support</a>
+<li><a href='prosupport.html'>Purchase</a>
+</ul>
+</div>
+<div class="searchmenu" id="searchmenu">
+<form method="GET" action="search">
+<select name="s" id="searchtype">
+<option value="d">Search Documentation</option>
+<option value="c">Search Changelog</option>
+</select>
+<input type="text" name="q" id="searchbox" value="">
+<input type="submit" value="Go">
+</form>
+</div>
+</div>
+<script>
+function toggle_div(nm) {
+var w = document.getElementById(nm);
+if( w.style.display=="block" ){
+w.style.display = "none";
+}else{
+w.style.display = "block";
+}
+}
+function toggle_search() {
+var w = document.getElementById("searchmenu");
+if( w.style.display=="block" ){
+w.style.display = "none";
+} else {
+w.style.display = "block";
+setTimeout(function(){
+document.getElementById("searchbox").focus()
+}, 30);
+}
+}
+function div_off(nm){document.getElementById(nm).style.display="none";}
+window.onbeforeunload = function(e){div_off("submenu");}
+/* Disable the Search feature if we are not operating from CGI, since */
+/* Search is accomplished using CGI and will not work without it. */
+if( !location.origin || !location.origin.match || !location.origin.match(/http/) ){
+document.getElementById("search_menubutton").style.display = "none";
+}
+/* Used by the Hide/Show button beside syntax diagrams, to toggle the */
+function hideorshow(btn,obj){
+var x = document.getElementById(obj);
+var b = document.getElementById(btn);
+if( x.style.display!='none' ){
+x.style.display = 'none';
+b.innerHTML='show';
+}else{
+x.style.display = '';
+b.innerHTML='hide';
+}
+return false;
+}
+var antiRobot = 0;
+function antiRobotGo(){
+if( antiRobot!=3 ) return;
+antiRobot = 7;
+var j = document.getElementById("mtimelink");
+if(j && j.hasAttribute("data-href")) j.href=j.getAttribute("data-href");
+}
+function antiRobotDefense(){
+document.body.onmousedown=function(){
+antiRobot |= 2;
+antiRobotGo();
+document.body.onmousedown=null;
+}
+document.body.onmousemove=function(){
+antiRobot |= 2;
+antiRobotGo();
+document.body.onmousemove=null;
+}
+setTimeout(function(){
+antiRobot |= 1;
+antiRobotGo();
+}, 100)
+antiRobotGo();
+}
+antiRobotDefense();
+</script>
+<div class=fancy>
+<div class=nosearch>
+<div class="fancy_title">
+The INDEXED BY Clause
+</div>
+</div>
+
+
+
+
+<h1 id="how_indexed_by_works"><span>1. </span>How INDEXED BY Works</h1>
+
+<p>The INDEXED BY phrase forces the <a href="optoverview.html">SQLite query planner</a> to use a
+particular named index on a <a href="lang_delete.html">DELETE</a>, <a href="lang_select.html">SELECT</a>, or <a href="lang_update.html">UPDATE</a> statement.
+The INDEXED BY phrase is an SQLite extension and
+is not portable to other SQL database engines.</p>
+
+<p><b><a href="syntax/qualified-table-name.html">qualified-table-name:</a></b>
+<button id='x5aa9a11d' onclick='hideorshow("x5aa9a11d","x7055a075")'>hide</button></p>
+ <div id='x7055a075' class='imgcontainer'>
+ <div style="max-width:599px"><svg xmlns='http://www.w3.org/2000/svg' class="pikchr" viewBox="0 0 599.746 182.736">
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+<path d="M9,17L39,17"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<path d="M60,32L156,32A15 15 0 0 0 171 17A15 15 0 0 0 156 2L60,2A15 15 0 0 0 45 17A15 15 0 0 0 60 32Z"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<text x="108" y="17" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">schema-name</text>
+<polygon points="195,17 183,21 183,12" style="fill:rgb(0,0,0)"/>
+<path d="M171,17L189,17"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
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+<text x="210" y="17" text-anchor="middle" font-weight="bold" fill="rgb(0,0,0)" dominant-baseline="central">.</text>
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+<path d="M276,32L351,32A15 15 0 0 0 366 17A15 15 0 0 0 351 2L276,2A15 15 0 0 0 261 17A15 15 0 0 0 276 32Z"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<text x="313" y="17" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">table-name</text>
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+<path d="M366,17 L 374,17 Q 381,17 381,30 Q 381,44 392,44 L 402,44"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<path d="M423,59L427,59A15 15 0 0 0 442 44L442,44A15 15 0 0 0 427 29L423,29A15 15 0 0 0 408 44L408,44A15 15 0 0 0 423 59Z"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<text x="425" y="44" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">AS</text>
+<polygon points="465,44 453,48 453,40" style="fill:rgb(0,0,0)"/>
+<path d="M442,44L459,44"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<path d="M480,59L501,59A15 15 0 0 0 516 44L516,44A15 15 0 0 0 501 29L480,29A15 15 0 0 0 465 44L465,44A15 15 0 0 0 480 59Z"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<text x="490" y="44" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">alias</text>
+<polygon points="539,44 527,48 527,40" style="fill:rgb(0,0,0)"/>
+<path d="M516,44L533,44"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<path d="M539,44 L 546,44 Q 554,44 554,51 L 554,59"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<polygon points="453,17 442,21 442,12" style="fill:rgb(0,0,0)"/>
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+<path d="M108,44 L 225,44 Q 240,44 240,30 Q 240,17 247,17 L 255,17"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<path d="M236,142L301,142A15 15 0 0 0 316 127A15 15 0 0 0 301 112L236,112A15 15 0 0 0 221 127A15 15 0 0 0 236 142Z"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<text x="268" y="127" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">INDEXED</text>
+<polygon points="339,127 327,131 327,123" style="fill:rgb(0,0,0)"/>
+<path d="M316,127L333,127"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<path d="M354,142L358,142A15 15 0 0 0 373 127A15 15 0 0 0 358 112L354,112A15 15 0 0 0 339 127A15 15 0 0 0 354 142Z"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<text x="356" y="127" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">BY</text>
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+<text x="451" y="127" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">index-name</text>
+<path d="M236,180L256,180A15 15 0 0 0 271 165A15 15 0 0 0 256 150L236,150A15 15 0 0 0 221 165A15 15 0 0 0 236 180Z"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
+<text x="246" y="165" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">NOT</text>
+<polygon points="294,165 283,169 283,161" style="fill:rgb(0,0,0)"/>
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+</svg>
+</div>
+</div>
+
+
+<p>The "INDEXED BY <span class='yyterm'>index-name</span>" phrase specifies 
+that the named index
+must be used in order to look up values on the preceding table.
+If <span class='yyterm'>index-name</span> does not exist or cannot be used 
+for the query, then the preparation of the SQL statement fails.
+The "NOT INDEXED" clause specifies that no index shall be used when
+accessing the preceding table, including implied indices create by
+UNIQUE and PRIMARY KEY constraints.  However, the <a href="lang_createtable.html#rowid">rowid</a>
+can still be used to look up entries even when "NOT INDEXED" is specified.</p>
+
+<p>Some SQL database engines provide non-standard "hint" mechanisms which
+can be used to give the query optimizer clues about what indices it should
+use for a particular statement.  The INDEXED BY clause of SQLite is 
+<em>not</em> a hinting mechanism and it should not be used as such.
+The INDEXED BY clause does not give the optimizer hints about which index
+to use; it gives the optimizer a requirement of which index to use.
+If the query optimizer is unable to use the index specified by the
+INDEXED BY clause, then the query will fail with an error.</p>
+
+<p>The INDEXED BY clause is <em>not</em> intended for use in tuning
+the performance of a query.  The intent of the INDEXED BY clause is
+to raise a run-time error if a schema change, such as dropping or
+creating an index, causes the query plan for a time-sensitive query
+to change.  The INDEXED BY clause is designed to help detect
+undesirable query plan changes during regression testing.
+Application 
+developers are admonished to omit all use of INDEXED BY during
+application design, implementation, testing, and tuning.  If
+INDEXED BY is to be used at all, it should be inserted at the very
+end of the development process when "locking down" a design.</p>
+
+<h1 id="see_also"><span>2. </span>See Also</h1>
+
+<ol>
+<li><p>The <a href="queryplanner-ng.html#howtofix">query planner checklist</a> describes steps that application
+developers should following to help resolve query planner problems.
+Notice the that the use of INDEXED BY is a last resort, to be used only
+when all other measures fail.</p>
+
+</li><li><p><a href="optoverview.html#uplus">The unary "+" operator</a>
+can be used to disqualify terms in the WHERE clause from use by indices.
+Careful use of unary + can sometimes help prevent the query planner from
+choosing a poor index without restricting it to using one specific index.
+Careful placement of unary + operators is a better method for controlling 
+which indices are used by a query.</p>
+
+</li><li><p>The <a href="c3ref/stmt_status.html">sqlite3_stmt_status()</a> C/C++ interface together with the
+<a href="c3ref/c_stmtstatus_counter.html#sqlitestmtstatusfullscanstep">SQLITE_STMTSTATUS_FULLSCAN_STEP</a> and <a href="c3ref/c_stmtstatus_counter.html#sqlitestmtstatussort">SQLITE_STMTSTATUS_SORT</a> verbs
+can be used to detect at run-time when an SQL statement is not
+making effective use of indices.  Many applications may prefer to
+use the <a href="c3ref/stmt_status.html">sqlite3_stmt_status()</a> interface to detect index misuse
+rather than the INDEXED BY phrase described here.</p>
+</li></ol>
+<p align="center"><small><i>This page last modified on  <a href="https://sqlite.org/docsrc/honeypot" id="mtimelink"  data-href="https://sqlite.org/docsrc/finfo/pages/lang_indexedby.in?m=f9785fa831">2022-01-08 05:02:57</a> UTC </small></i></p>
+
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-13 14:07:11 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-13 14:07:11 +0000
commit	63847496f14c813a5d80efd5b7de0f1294ffe1e3 (patch)
tree	01c7571c7c762ceee70638549a99834fdd7c411b /www/lang_indexedby.html
parent	Initial commit. (diff)
download	sqlite3-63847496f14c813a5d80efd5b7de0f1294ffe1e3.tar.xz sqlite3-63847496f14c813a5d80efd5b7de0f1294ffe1e3.zip