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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html><head><title>SQLite: Most Widely Deployed SQL Database</title><style type="text/css">body { margin: auto; font-family: "Verdana" "sans-serif"; padding: 8px 1%;}a { color: #45735f }a:visited { color: #734559 }.logo { position:absolute; margin:3px; }.tagline { float:right; text-align:right; font-style:italic; width:240px; margin:12px; margin-top:58px;}.toolbar { font-variant: small-caps; text-align: center; line-height: 1.6em; margin: 0; padding:1px 8px;}.toolbar a { color: white; text-decoration: none; padding: 6px 12px; }.toolbar a:visited { color: white; }.toolbar a:hover { color: #80a796; background: white; }.content { margin: 5%; }.content dt { font-weight:bold; }.content dd { margin-bottom: 25px; margin-left:20%; }.content ul { padding:0px; padding-left: 15px; margin:0px; }/* rounded corners */.se { background: url(images/se.png) 100% 100% no-repeat #80a796}.sw { background: url(images/sw.png) 0% 100% no-repeat }.ne { background: url(images/ne.png) 100% 0% no-repeat }.nw { background: url(images/nw.png) 0% 0% no-repeat }</style><meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head><body><div><!-- container div to satisfy validator --><a href="index.html"><img class="logo" src="images/SQLite.gif" alt="SQLite Logo" border="0"></a><div><!-- IE hack to prevent disappearing logo--></div><div class="tagline">Small. Fast. Reliable.<br>Choose any three.</div><table width=100% style="clear:both"><tr><td> <div class="se"><div class="sw"><div class="ne"><div class="nw"> <div class="toolbar"> <a href="about.html">About</a> <a href="sitemap.html">Sitemap</a> <a href="docs.html">Documentation</a> <a href="download.html">Download</a> <a href="copyright.html">License</a> <a href="news.html">News</a> <a href="http://www.sqlite.org/cvstrac/index">Developers</a> <a href="support.html">Support</a> </div></div></div></div></div></td></tr></table> <h2>Most Widely Deployed SQL Database</h2><p>We <em>believe</em> that there are more copies of SQLitein use around the world than any other SQL database engine,and possibly all other SQL database engines combined. We cannotbe certain of this since we have no way of measuring eitherthe number of SQLite deployments nor the number of deploymentsof other databases. But we believe the claim is defensible.</p><p>The belief that SQLite is the most widely deployed SQLdatabase engine stems from its use as an embedded database.Other database engines, such as MySQL, PostgreSQL, or Oracle,are typically found one to a server. And usually a singleserver can serve multiple users. With SQLite, on the otherhand, a single user will typically have exclusive use ofmultiple copies of SQLite. SQLite is used on servers, butit is also used on desktop PC, and in cellphones, and PDAs,and MP3-players, and set-top boxes.</p><h3>Estimates</h3><p>At the end of 2006, there were 100 million websites on the internet.<a href="http://news.netcraft.com/archives/2006/11/01/november_2006_web_server_survey.html">[1]</a>Let us use that number as a proxy for the number of deployedSQL database engines other than SQLite. Not every websiteruns an SQL database engine, and not ever SQL database engineruns a website. Larger websites run multipledatabase engines. But the vast majority of smaller websites(the long tail) sharea database engine with several other websites,if they use a database engine at all.And many large SQL database installations have nothing to do withwebsites.So using the number of websites as a surrogate for the number of operationalSQL database engines is a crude approximation, but it is the bestwe have so we will go with it. (Readers are encouraged to submitbetter estimates.)</p><p>Now let's consider where SQLite is used:</p><ul><li>125 million copies of Mozilla Firefox <a href="http://arstechnica.com/news.ars/post/20071202-mozilla-coo-over-125-million-people-use-firefox.html">[2]</a></li><li>20 million Mac computers, each of which contains multiplecopies of SQLite</li><li>20 million websites run PHP which has SQLite built in. <a href="http://www.php.net/usage.php">[3]</a> We have noway of estimating what fraction of those sites actively useSQLite, but we think it is a significant fraction.</li><li>300 million downloads of the <a href="http://www.skype.com/">Skype</a>client software and 100 million registered users<a href="http://skypejournal.com/blog/archives/2006/04/how_many_users_does_skype_have_today.php">[4]</a>. All recent versions of the Skypeclient use SQLite internally.</li><li>20 million Symbian smartphones shipped in Q3 2007<a href="http://www.symbian.com/news/pr/2007/pr20079552.html">[5]</a>Newer versions of the SymbianOS have SQLite built in. It is unclearexactly how many Symbian phones actually contain SQLite, so we willuse a single quarter's sales as a lower bound.</li><li>10 million AOL subscribers use SQLite in the AOL email client thatcomes bundled with their subscription.</li><li>10 million Solaris 10 installations, all of which require SQLite inorder to boot.</li><li>Millions and millions of copies of<a href="http://www.mcafee.com/">McAfee</a> anti-virus software alluse SQLite internally.</li><li>Millions of iPhones use SQLite</li><li>Millions and millions of other cellphones from manufactures other than Symbian and Apple use SQLite.This has not been publicly acknowledged by the manufacturesbut it is known to the SQLite developers.</li><li>There are perhaps millions of additional deployments ofSQLite that the SQLite developers do not know about.</li></ul><p>By these estimates, we see 200 or 300 million SQLite deploymentsand about 100 million deployments of other SQL database engines. Theseestimates are obviously very rough and may be off significantly. But there is a wide margin. So the SQLitedevelopers think it is likely that SQLite is the most widely deployedSQL database engine in the world.</p><hr><small><i>This page last modified 2008/03/03 13:41:48 UTC</i></small></div></body></html>⌨️ 快捷键说明
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