diff options
Diffstat (limited to '')
| -rw-r--r-- | www/35to36.html | 355 |
1 files changed, 355 insertions, 0 deletions
diff --git a/www/35to36.html b/www/35to36.html new file mode 100644 index 0000000..f4a348a --- /dev/null +++ b/www/35to36.html @@ -0,0 +1,355 @@ +<!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>SQLite Changes From Version 3.5.9 To 3.6.0</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> + +<h1> Moving From SQLite 3.5.9 to 3.6.0</h1><p> + SQLite version 3.6.0 (2008-07-16) + contains many changes. As is the custom with + the SQLite project, most changes are fully backwards compatible. + However, a few of the changes in version 3.6.0 are incompatible and + might require modifications to application code and/or makefiles. + This document is a briefing on the changes in SQLite 3.6.0 + with special attention to the incompatible changes. +</p> +<blockquote> + <strong>Key Points:</strong> + <ul> + <li> The database file format is unchanged. </li> + <li> All incompatibilities are on obscure interfaces and hence should + have zero impact on most applications. </li> + </ul> +</blockquote> +<h2>1.0 Incompatible Changes</h2><p> + Incompatible changes are covered first since they are the most + important to maintainers and programmers. +</p> +<h3>1.1 Overview Of Incompatible Changes</h3><p> + <ol> + <li><p>Changes to the <a href="c3ref/vfs.html">sqlite3_vfs</a> object</p> + + <ol type="a"> + <li><p>The signature of the xAccess method has been modified to + return an <a href="rescode.html">error code</a> and to store its output into an integer pointed + to by a parameter, rather than returning the output directly. + This change allows the xAccess() method to report failures. + In association with this signature change, a new + extended error code <a href="rescode.html#ioerr_access">SQLITE_IOERR_ACCESS</a> has been added. + </p></li> + + <li><p>The xGetTempname method has been removed from <a href="c3ref/vfs.html">sqlite3_vfs</a>. + In its place, the xOpen method is enhanced to open a temporary file + of its own invention when the filename parameter is NULL.</p></li> + + <li><p>Added the xGetLastError() method to <a href="c3ref/vfs.html">sqlite3_vfs</a> for returning + filesystem-specific error messages and error codes back to + SQLite.</p></li> + </ol> + </li> + + <li><p>The signature of the xCheckReservedLock method on <a href="c3ref/io_methods.html">sqlite3_io_methods</a> + has been modified so that it returns an <a href="rescode.html">error code</a> and stores its + boolean result into an integer pointed to by a parameter. In + association with this change, a new extended error code + <a href="rescode.html#ioerr_checkreservedlock">SQLITE_IOERR_CHECKRESERVEDLOCK</a> has been added.</p></li> + + <li><p>When SQLite is ported to new operating systems (operating systems + other than Unix, Windows, and OS/2 for which ports are provided together + with the core) + two new functions, <a href="c3ref/initialize.html">sqlite3_os_init()</a> and <a href="c3ref/initialize.html">sqlite3_os_end()</a>, must + be provided as part of the port.</p></li> + + <li><p>The way in which the IN and NOT IN operators handle NULL values + in their right-hand expressions has been brought into compliance with + the SQL standard and with other SQL database engines.</p></li> + + <li><p>The column names for the result sets of <a href="lang_select.html">SELECT</a> statements have + been tweaked in some cases to work more like other SQL database + engines.</p></li> + + <li><p>Changes to compile-time options:</p> + + <ol type="a"> + <li><p>The SQLITE_MUTEX_APPDEF compile-time parameter is no longer + recognized. As a replacement, alternative + <a href="c3ref/mutex_alloc.html">mutex implementations</a> may be created + at runtime using <a href="c3ref/config.html">sqlite3_config()</a> with the <a href="c3ref/c_config_covering_index_scan.html#sqliteconfigmutex">SQLITE_CONFIG_MUTEX</a> + operator and the <a href="c3ref/mutex_methods.html">sqlite3_mutex_methods</a> object.</p></li> + + <li><p>Compile-time options OS_UNIX, OS_WIN, OS_OS2, OS_OTHER, and + TEMP_STORE have been renamed to include an "SQLITE_" prefix in order + to help avoid namespace collisions with application software. The + new names of these options are respectively: + SQLITE_OS_UNIX, SQLITE_OS_WIN, SQLITE_OS_OS2, SQLITE_OS_OTHER, + and <a href="compile.html#temp_store">SQLITE_TEMP_STORE</a>.</p></li> + </ol> + </li> + </ol> +</p> +<h3>1.2 Changes To The VFS Layer</h3><p> + SQLite <a href="releaselog/3_5_0.html">version 3.5.0</a> introduced a <a href="34to35.html">new OS interface layer</a> that + provided an abstraction of the underlying operating system. + This was an important innovation and has proven to be helpful + in porting and maintaining SQLite. + However, the developers have discovered some minor flaws in the + original "virtual file system" design introduced in version 3.5.0 + and so SQLite 3.6.0 includes some small incompatible changes + to address these flaws. +</p> +<blockquote> + <strong>Key Point:</strong> The incompatible + changes in the SQLite operating-system interface for version 3.6.0 + only affect the rare applications that make use of the + <a href="c3ref/vfs.html">virtual file system</a> interface or that + supply an application-defined <a href="c3ref/mutex_alloc.html">mutex implementation</a> + or that make use of other obscure compile-time options. The + changes introduced by SQLite version 3.6.0 will have zero impact on the + vast majority of SQLite applications that use the built-in interfaces + to Unix, Windows, and OS/2 and that use the standard build configuration. +</blockquote> +<h3>1.3 Changes In The Way The IN Operator Handles NULLs</h3><p> + All versions of SQLite up to and including version 3.5.9 have mishandled + NULL values on the right-hand side of IN and NOT IN operators. + Specifically, SQLite has previously ignored NULLs on the right-hand side + of IN and NOT IN. +</p> +<p> + Suppose we have a table X1 defined as follows: +</p> +<blockquote><pre> + CREATE TABLE x1(x INTEGER); + INSERT INTO x1 VALUES(1); + INSERT INTO x1 VALUES(2); + INSERT INTO x1 VALUES(NULL); +</pre></blockquote><p> + Given the definition of X1 above, the following expressions have + historically evaluated to FALSE in SQLite, though the correct + answer is actually NULL: +</p> +<blockquote><pre> + 3 IN (1,2,NULL) + 3 IN (SELECT * FROM x1) +</pre></blockquote><p> + Similarly, the following expressions have historically evaluated to + TRUE when in fact NULL is also the correct answer here: +</p> +<blockquote><pre> + 3 NOT IN (1,2,NULL) + 3 NOT IN (SELECT * FROM x1) +</pre></blockquote><p> + The historical behavior of SQLite is incorrect according to the SQL:1999 + standard and it is inconsistent with the behavior of MySQL and + PostgreSQL. Version 3.6.0 changes the behavior of the IN and + NOT IN operators to conform to the standard and to give the same + results as other SQL database engines. +</p> +<blockquote> + <strong>Key Point:</strong> The change to the way NULL values are handled + by the IN and NOT IN operators is technically a bug fix, not a design + change. However, maintainers should check to ensure that applications + do not depend on the older, buggy behavior prior to upgrading to + version 3.6.0. +</blockquote> +<h3>1.4 Changes To Column Naming Rules</h3><p> + The column names reported by join subqueries have been modified slightly + in order to work more like other database engines. Consider the following + query: +</p> +<blockquote><pre> + CREATE TABLE t1(a); + CREATE TABLE t2(x); + SELECT * FROM (SELECT t1.a FROM t1 JOIN t2 ORDER BY t2.x LIMIT 1) ORDER BY 1; +</pre></blockquote><p> + In version 3.5.9 the query above would return a single column named "t1.a". + In version 3.6.0 the column name is just "a". +</p> +<p> + SQLite has never made any promises about the names of columns in the + result set of <a href="lang_select.html">SELECT</a> statement unless the column contains an AS clause. + So this change to column name is technically not an incompatibility. + SQLite is merely changing from one undefined behavior to another. + Nevertheless, many applications depend on the unspecified column naming + behavior of SQLite and so this change is discussed under the + incompatible changes subheading. +</p> +<h3>1.5 Changes To Compile-Time Options</h3><p> + Compile-time options to SQLite are controlled by C-preprocessor + macros. SQLite version 3.6.0 changes the names of some of these + macros so that all C-preprocessor macros that are specific to + SQLite begin with the "SQLITE_" prefix. This is done to reduce the + risk of name collisions with other software modules. +</p> +<blockquote> + <strong>Key Point:</strong> Changes to compile-time options have the + potential to affect makefiles in projects that do customized builds of + SQLite. These changes should have zero impact on application code and for + most projects which use a standard, default build of SQLite. +</blockquote> +<h2>2.0 Fully Backwards-Compatible Enhancements</h2><p> + In addition to the incompatible changes listed above, SQLite + version 3.6.0 adds the following backwards compatible changes and + enhancements: +</p> +<p> + <ol> + + <li value="7"><p>The new <a href="c3ref/config.html">sqlite3_config()</a> interface allows an application + to customize the behavior of SQLite at run-time. Customizations possible + using <a href="c3ref/config.html">sqlite3_config()</a> include the following:</p> + <ol type="a"> + <li><p>Specify an alternative mutex implementation using the + <a href="c3ref/c_config_covering_index_scan.html#sqliteconfigmutex">SQLITE_CONFIG_MUTEX</a> verb with the <a href="c3ref/mutex_methods.html">sqlite3_mutex_methods</a> object.</p></li> + <li><p>Specify an alternative malloc implementation using the + <a href="c3ref/c_config_covering_index_scan.html#sqliteconfigmalloc">SQLITE_CONFIG_MALLOC</a> verb with the <a href="c3ref/mem_methods.html">sqlite3_mem_methods</a> object.</p></li> + <li><p>Partially or fully disable the use of mutexes using + <a href="c3ref/c_config_covering_index_scan.html#sqliteconfigsinglethread">SQLITE_CONFIG_SINGLETHREAD</a>, <a href="c3ref/c_config_covering_index_scan.html#sqliteconfigmultithread">SQLITE_CONFIG_MULTITHREAD</a> and + <a href="c3ref/c_config_covering_index_scan.html#sqliteconfigserialized">SQLITE_CONFIG_SERIALIZED</a>.</p></li> + </ol> + </li> + + <li><p>A new flag <a href="c3ref/c_open_autoproxy.html">SQLITE_OPEN_NOMUTEX</a> is made available to the + <a href="c3ref/open.html">sqlite3_open_v2()</a> interface.</p></li> + + <li><p>The new <a href="c3ref/status.html">sqlite3_status()</a> interface allows an application to query + the performance status of SQLite at runtime. + </p></li> + + <li><p>The <a href="c3ref/memory_highwater.html">sqlite3_memory_used()</a> and <a href="c3ref/memory_highwater.html">sqlite3_memory_highwater()</a> + interfaces are deprecated. The equivalent functionality is now available + through <a href="c3ref/status.html">sqlite3_status()</a>.</p></li> + + <li><p>The <a href="c3ref/initialize.html">sqlite3_initialize()</a> interface can be called to explicitly + initialize the SQLite subsystem. The <a href="c3ref/initialize.html">sqlite3_initialize()</a> interface is + called automatically when invoking certain interfaces so the use of + <a href="c3ref/initialize.html">sqlite3_initialize()</a> is not required, but it is recommended.</p></li> + + <li><p>The <a href="c3ref/initialize.html">sqlite3_shutdown()</a> interface causes SQLite to release any + system resources (memory allocations, mutexes, open file handles) + that might have been allocated by <a href="c3ref/initialize.html">sqlite3_initialize()</a>.</p></li> + + <li><p>The <a href="c3ref/next_stmt.html">sqlite3_next_stmt()</a> interface allows an application to discover + all <a href="c3ref/stmt.html">prepared statements</a> associated with a <a href="c3ref/sqlite3.html">database connection</a>.</p></li> + + <li><p>Added the <a href="pragma.html#pragma_page_count">page_count</a> PRAGMA for returning the size of the underlying + database file in pages.</p></li> + + <li><p>Added a new <a href="rtree.html">R*Tree index extension</a>.</p></li> + + </ol> +</p> + +<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/35to36.in?m=f555d66703e47ed95">2016-09-28 14:07:03</a> UTC </small></i></p> + |