📄 function.sqlite-popen.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Opens a persistent handle to an SQLite database and create the database if it does not exist</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.sqlite-open.html">sqlite_open</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.sqlite-prev.html">sqlite_prev</a></div> <div class="up"><a href="ref.sqlite.html">SQLite Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.sqlite-popen" class="refentry"> <div class="refnamediv"> <h1 class="refname">sqlite_popen</h1> <p class="verinfo">(PHP 5, PECL sqlite:1.0-1.0.3)</p><p class="refpurpose"><span class="refname">sqlite_popen</span> — <span class="dc-title"> Opens a persistent handle to an SQLite database and create the database if it does not exist </span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">resource</span> <span class="methodname"><b><b>sqlite_popen</b></b></span> ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$filename</tt></span> [, <span class="methodparam"><span class="type">int</span> <tt class="parameter">$mode</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter reference">&$error_message</tt></span> ]] )</div> <p class="simpara"> This function behaves identically to <a href="function.sqlite-open.html" class="function">sqlite_open()</a> except that is uses the persistent resource mechanism of PHP. For information about the meaning of the parameters, read the <a href="function.sqlite-open.html" class="function">sqlite_open()</a> manual page. </p> <p class="para"> <b>sqlite_popen()</b> will first check to see if a persistent handle has already been opened for the given <i><tt class="parameter">filename</tt></i>. If it finds one, it returns that handle to your script, otherwise it opens a fresh handle to the database. </p> <p class="para"> The benefit of this approach is that you don't incur the performance cost of re-reading the database and index schema on each page hit served by persistent web server SAPI's (any SAPI except for regular CGI or CLI). </p> <blockquote><p><b class="note">Note</b>: <span class="simpara"> If you use persistent handles and have the database updated by a background process (perhaps via a crontab), and that process re-creates the database by overwriting it (either by unlinking and rebuilding, or moving the updated version to replace the current version), you may experience undefined behaviour when a persistent handle on the old version of the database is recycled. </span> <span class="simpara"> To avoid this situation, have your background processes open the same database file and perform their updates in a transaction. </span> </p></blockquote> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">filename</tt></i></span> <dd> <p class="para"> The filename of the SQLite database. If the file does not exist, SQLite will attempt to create it. PHP must have write permissions to the file if data is inserted, the database schema is modified or to create the database if it does not exist. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">mode</tt></i></span> <dd> <p class="para"> The mode of the file. Intended to be used to open the database in read-only mode. Presently, this parameter is ignored by the sqlite library. The default value for mode is the octal value <i>0666</i> and this is the recommended value. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">error_message</tt></i></span> <dd> <p class="para"> Passed by reference and is set to hold a descriptive error message explaining why the database could not be opened if there was an error. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns a resource (database handle) on success, <b><tt>FALSE</tt></b> on error. </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="function.sqlite-open.html" class="function" rel="rdfs-seeAlso">sqlite_open()</a></li> <li class="member"><a href="function.sqlite-close.html" class="function" rel="rdfs-seeAlso">sqlite_close()</a></li> <li class="member"><a href="function.sqlite-factory.html" class="function" rel="rdfs-seeAlso">sqlite_factory()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.sqlite-open.html">sqlite_open</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.sqlite-prev.html">sqlite_prev</a></div> <div class="up"><a href="ref.sqlite.html">SQLite Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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