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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html><head><title>Opening A New Database Connection</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> <a href="intro.html"><h2>SQLite C Interface</h2></a><h2>Opening A New Database Connection</h2><blockquote><pre>int sqlite3_open( const char *filename, /* Database filename (UTF-8) */ sqlite3 **ppDb /* OUT: SQLite db handle */);int sqlite3_open16( const void *filename, /* Database filename (UTF-16) */ sqlite3 **ppDb /* OUT: SQLite db handle */);int sqlite3_open_v2( const char *filename, /* Database filename (UTF-8) */ sqlite3 **ppDb, /* OUT: SQLite db handle */ int flags, /* Flags */ const char *zVfs /* Name of VFS module to use */);</pre></blockquote><p>These routines open an SQLite database file whose nameis given by the filename argument.The filename argument is interpreted as UTF-8for <a href="../c3ref/open.html">sqlite3_open()</a> and <a href="../c3ref/open.html">sqlite3_open_v2()</a> and as UTF-16in the native byte order for <a href="../c3ref/open.html">sqlite3_open16()</a>.An <a href="../c3ref/sqlite3.html">sqlite3*</a> handle is usually returned in *ppDb, evenif an error occurs. The only exception is if SQLite is unableto allocate memory to hold the <a href="../c3ref/sqlite3.html">sqlite3</a> object, a NULL willbe written into *ppDb instead of a pointer to the <a href="../c3ref/sqlite3.html">sqlite3</a> object.If the database is opened (and/or created)successfully, then <a href="../c3ref/c_abort.html">SQLITE_OK</a> is returned. Otherwise anerror code is returned. The<a href="../c3ref/errcode.html">sqlite3_errmsg()</a> or <a href="../c3ref/errcode.html">sqlite3_errmsg16()</a> routines can be used to obtainan English language description of the error.</p><p>The default encoding for the database will be UTF-8 if<a href="../c3ref/open.html">sqlite3_open()</a> or <a href="../c3ref/open.html">sqlite3_open_v2()</a> is called andUTF-16 in the native byte order if <a href="../c3ref/open.html">sqlite3_open16()</a> is used.</p><p>Whether or not an error occurs when it is opened, resourcesassociated with the <a href="../c3ref/sqlite3.html">sqlite3*</a> handle should be released by passing itto <a href="../c3ref/close.html">sqlite3_close()</a> when it is no longer required.</p><p>The <a href="../c3ref/open.html">sqlite3_open_v2()</a> interface works like <a href="../c3ref/open.html">sqlite3_open()</a>except that it acccepts two additional parameters for additional controlover the new database connection. The flags parameter can beone of:</p><p><ol><li> <a href="../c3ref/c_open_create.html">SQLITE_OPEN_READONLY</a><li> <a href="../c3ref/c_open_create.html">SQLITE_OPEN_READWRITE</a><li> <a href="../c3ref/c_open_create.html">SQLITE_OPEN_READWRITE</a> | <a href="../c3ref/c_open_create.html">SQLITE_OPEN_CREATE</a></ol></p><p>The first value opens the database read-only.If the database does not previously exist, an error is returned.The second option opensthe database for reading and writing if possible, or reading only ifif the file is write protected. In either case the databasemust already exist or an error is returned. The third optionopens the database for reading and writing and creates it if it doesnot already exist.The third options is behavior that is always used for <a href="../c3ref/open.html">sqlite3_open()</a>and <a href="../c3ref/open.html">sqlite3_open16()</a>.</p><p>If the filename is ":memory:", then an privatein-memory database is created for the connection. This in-memorydatabase will vanish when the database connection is closed. Futureversion of SQLite might make use of additional special filenamesthat begin with the ":" character. It is recommended thatwhen a database filename really does begin with":" that you prefix the filename with a pathname like "./" toavoid ambiguity.</p><p>If the filename is an empty string, then a private temporaryon-disk database will be created. This private database will beautomatically deleted as soon as the database connection is closed.</p><p>The fourth parameter to sqlite3_open_v2() is the name of the<a href="../c3ref/vfs.html">sqlite3_vfs</a> object that defines the operating systeminterface that the new database connection should use. If thefourth parameter is a NULL pointer then the default <a href="../c3ref/vfs.html">sqlite3_vfs</a>object is used.</p><p><b>Note to windows users:</b> The encoding used for the filename argumentof <a href="../c3ref/open.html">sqlite3_open()</a> and <a href="../c3ref/open.html">sqlite3_open_v2()</a> must be UTF-8, not whatevercodepage is currently defined. Filenames containing internationalcharacters must be converted to UTF-8 prior to passing them into<a href="../c3ref/open.html">sqlite3_open()</a> or <a href="../c3ref/open.html">sqlite3_open_v2()</a>.</p><p><h3>Invariants:</h3><table border="0" cellpadding="5" cellspacing="0"><tr><td valign="top">F12701</td> <td valign="top">The <a href="../c3ref/open.html">sqlite3_open()</a>, <a href="../c3ref/open.html">sqlite3_open16()</a>, and<a href="../c3ref/open.html">sqlite3_open_v2()</a> interfaces create a new<a href="../c3ref/sqlite3.html">database connection</a> associated withthe database file given in their first parameter.</td></tr><tr><td valign="top">F12702</td> <td valign="top">The filename argument is interpreted as UTF-8for <a href="../c3ref/open.html">sqlite3_open()</a> and <a href="../c3ref/open.html">sqlite3_open_v2()</a> and as UTF-16in the native byte order for <a href="../c3ref/open.html">sqlite3_open16()</a>.</td></tr><tr><td valign="top">F12703</td> <td valign="top">A successful invocation of <a href="../c3ref/open.html">sqlite3_open()</a>, <a href="../c3ref/open.html">sqlite3_open16()</a>,or <a href="../c3ref/open.html">sqlite3_open_v2()</a> writes a pointer to a new<a href="../c3ref/sqlite3.html">database connection</a> into *ppDb.</td></tr><tr><td valign="top">F12704</td> <td valign="top">The <a href="../c3ref/open.html">sqlite3_open()</a>, <a href="../c3ref/open.html">sqlite3_open16()</a>, and<a href="../c3ref/open.html">sqlite3_open_v2()</a> interfaces return <a href="../c3ref/c_abort.html">SQLITE_OK</a> upon success,or an appropriate <a href="../c3ref/c_abort.html">error code</a> on failure.</td></tr><tr><td valign="top">F12706</td> <td valign="top">The default text encoding for a new database created using<a href="../c3ref/open.html">sqlite3_open()</a> or <a href="../c3ref/open.html">sqlite3_open_v2()</a> will be UTF-8.</td></tr><tr><td valign="top">F12707</td> <td valign="top">The default text encoding for a new database created using<a href="../c3ref/open.html">sqlite3_open16()</a> will be UTF-16.</td></tr><tr><td valign="top">F12709</td> <td valign="top">The <a href="../c3ref/open.html">sqlite3_open(F,D)</a> interface is equivalent to<a href="../c3ref/open.html">sqlite3_open_v2(F,D,G,0)</a> where the G parameter is<a href="../c3ref/c_open_create.html">SQLITE_OPEN_READWRITE</a>|<a href="../c3ref/c_open_create.html">SQLITE_OPEN_CREATE</a>.</td></tr><tr><td valign="top">F12711</td> <td valign="top">If the G parameter to <a href="../c3ref/open.html">sqlite3_open_v2(F,D,G,V)</a> contains thebit value <a href="../c3ref/c_open_create.html">SQLITE_OPEN_READONLY</a> then the database is openedfor reading only.</td></tr><tr><td valign="top">F12712</td> <td valign="top">If the G parameter to <a href="../c3ref/open.html">sqlite3_open_v2(F,D,G,V)</a> contains thebit value <a href="../c3ref/c_open_create.html">SQLITE_OPEN_READWRITE</a> then the database is openedreading and writing if possible, or for reading only if thefile is write protected by the operating system.</td></tr><tr><td valign="top">F12713</td> <td valign="top">If the G parameter to <a href="../c3ref/open.html">sqlite3_open(v2(F,D,G,V)</a> omits thebit value <a href="../c3ref/c_open_create.html">SQLITE_OPEN_CREATE</a> and the database does notpreviously exist, an error is returned.</td></tr><tr><td valign="top">F12714</td> <td valign="top">If the G parameter to <a href="../c3ref/open.html">sqlite3_open(v2(F,D,G,V)</a> contains thebit value <a href="../c3ref/c_open_create.html">SQLITE_OPEN_CREATE</a> and the database does notpreviously exist, then an attempt is made to create andinitialize the database.</td></tr><tr><td valign="top">F12717</td> <td valign="top">If the filename argument to <a href="../c3ref/open.html">sqlite3_open()</a>, <a href="../c3ref/open.html">sqlite3_open16()</a>,or <a href="../c3ref/open.html">sqlite3_open_v2()</a> is ":memory:", then an private,ephemeral, in-memory database is created for the connection.<font color="red">(TODO: Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE requiredin sqlite3_open_v2()?)</font></td></tr><tr><td valign="top">F12719</td> <td valign="top">If the filename is an empty string, then a private, ephermeralon-disk database will be created.<font color="red">(TODO: Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE requiredin sqlite3_open_v2()?)</font></td></tr><tr><td valign="top">F12721</td> <td valign="top">The <a href="../c3ref/sqlite3.html">database connection</a> created by<a href="../c3ref/open.html">sqlite3_open_v2(F,D,G,V)</a> will use the<a href="../c3ref/vfs.html">sqlite3_vfs</a> object identified by the V parameter, orthe default <a href="../c3ref/vfs.html">sqlite3_vfs</a> object is V is a NULL pointer.</td></tr></table></p><p>See also lists of <a href="objlist.html">Objects</a>, <a href="constlist.html">Constants</a>, and <a href="funclist.html">Functions</a>.</p><hr><small<i>This page last modified 2008/01/31 20:37:13 UTC</i></small></div></body></html>⌨️ 快捷键说明
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