changes.html

这是sqlite3.56的文档。拿来给大家阅读使用

<li>SQLITE_SECURE_DELETE compile-time option causes deletes to overwrite
    old data with zeros.</li>
<li>Detect integer overflow in abs().</li>
<li>The random() function provides 64 bits of randomness instead of
    only 32 bits.</li>
<li>Parser detects and reports automaton stack overflow.</li>
<li>Change the round() function to return REAL instead of TEXT.</li>
<li>Allow WHERE clause terms on the left table of a LEFT OUTER JOIN to
    contain aggregate subqueries.</li>
<li>Skip over leading spaces in text to numeric conversions.</li>
<li>Various minor bug and documentation typo fixes and
    performance enhancements.</li>
</ul></p>
<a name="version_3_3_4"></a>
<h3>2006 February 11 (3.3.4)</h3>
<p><ul>
<li>Fix a blunder in the Unix mutex implementation that can lead to
deadlock on multithreaded systems.</li>
<li>Fix an alignment problem on 64-bit machines</li>
<li>Added the fullfsync pragma.</li>
<li>Fix an optimizer bug that could have caused some unusual LEFT OUTER JOINs
to give incorrect results.</li>
<li>The SUM function detects integer overflow and converts to accumulating
an approximate result using floating point numbers</li>
<li>Host parameter names can begin with '@' for compatibility with SQL Server.
</li>
<li>Other miscellaneous bug fixes</li>
</ul></p>
<a name="version_3_3_3"></a>
<h3>2006 January 31 (3.3.3)</h3>
<p><ul>
<li>Removed support for an ON CONFLICT clause on CREATE INDEX - it never
worked correctly so this should not present any backward compatibility
problems.</li>
<li>Authorizer callback now notified of ALTER TABLE ADD COLUMN commands</li>
<li>After any changes to the TEMP database schema, all prepared statements
are invalidated and must be recreated using a new call to
sqlite3_prepare()</li>
<li>Other minor bug fixes in preparation for the first stable release
of version 3.3</li>
</ul></p>
<h3>2006 January 24 (3.3.2 beta)</h3>
<p><ul>
<li>Bug fixes and speed improvements.  Improved test coverage.</li>
<li>Changes to the OS-layer interface: mutexes must now be recursive.</li>
<li>Discontinue the use of thread-specific data for out-of-memory
exception handling</li>
</ul></p>
<h3>2006 January 16 (3.3.1 alpha)</h3>
<p><ul>
<li>Countless bug fixes</li>
<li>Speed improvements</li>
<li>Database connections can now be used by multiple threads, not just
the thread in which they were created.</li>
</ul></p>
<h3>2006 January 10 (3.3.0 alpha)</h3>
<p><ul>
<li>CHECK constraints</li>
<li>IF EXISTS and IF NOT EXISTS clauses on CREATE/DROP TABLE/INDEX.</li>
<li>DESC indices</li>
<li>More efficient encoding of boolean values resulting in smaller database
files</li>
<li>More aggressive SQLITE_OMIT_FLOATING_POINT</li>
<li>Separate INTEGER and REAL affinity</li>
<li>Added a virtual function layer for the OS interface</li>
<li>"exists" method added to the TCL interface</li>
<li>Improved response to out-of-memory errors</li>
<li>Database cache can be optionally shared between connections
in the same thread</li>
<li>Optional READ UNCOMMITTED isolation (instead of the default
isolation level of SERIALIZABLE) and table level locking when
database connections share a common cache.</li>
</ul></p>
<a name="version_3_2_8"></a>
<h3>2005 December 19 (3.2.8)</h3>
<p><ul>
<li>Fix an obscure bug that can cause database corruption under the
following unusual circumstances: A large INSERT or UPDATE statement which 
is part of an even larger transaction fails due to a uniqueness contraint
but the containing transaction commits.</li>
</ul></p>
<a name="version_2_8_17"></a>
<h3>2005 December 19 (2.8.17)</h3>
<p><ul>
<li>Fix an obscure bug that can cause database corruption under the
following unusual circumstances: A large INSERT or UPDATE statement which 
is part of an even larger transaction fails due to a uniqueness contraint
but the containing transaction commits.</li>
</ul></p>
<a name="version_3_2_7"></a>
<h3>2005 September 24 (3.2.7)</h3>
<p><ul>
<li>GROUP BY now considers NULLs to be equal again, as it should
</li>
<li>Now compiles on Solaris and OpenBSD and other Unix variants
that lack the fdatasync() function</li>
<li>Now compiles on MSVC++6 again</li>
<li>Fix uninitialized variables causing malfunctions for various obscure
queries</li>
<li>Correctly compute a LEFT OUTER JOINs that is constrained on the
left table only</li>
</ul></p>
<a name="version_3_2_6"></a>
<h3>2005 September 17 (3.2.6)</h3>
<p><ul>
<li>Fix a bug that can cause database corruption if a VACUUM (or
    autovacuum) fails and is rolled back on a database that is
    larger than 1GiB</li>
<li>LIKE optiization now works for columns with COLLATE NOCASE</li>
<li>ORDER BY and GROUP BY now use bounded memory</li>
<li>Added support for COUNT(DISTINCT expr)</li>
<li>Change the way SUM() handles NULL values in order to comply with
    the SQL standard</li>
<li>Use fdatasync() instead of fsync() where possible in order to speed
    up commits slightly</li>
<li>Use of the CROSS keyword in a join turns off the table reordering
    optimization</li>
<li>Added the experimental and undocumented EXPLAIN QUERY PLAN capability</li>
<li>Use the unicode API in windows</li>
</ul></p>
<a name="version_3_2_5"></a>
<h3>2005 August 27 (3.2.5)</h3>
<p><ul>
<li>Fix a bug effecting DELETE and UPDATE statements that changed
more than 40960 rows.</li>
<li>Change the makefile so that it no longer requires GNUmake extensions</li>
<li>Fix the --enable-threadsafe option on the configure script</li>
<li>Fix a code generator bug that occurs when the left-hand side of an IN
operator is constant and the right-hand side is a SELECT statement</li>
<li>The PRAGMA synchronous=off statement now disables syncing of the
master journal file in addition to the normal rollback journals</li>
</ul></p>
<a name="version_3_2_4"></a>
<h3>2005 August 24 (3.2.4)</h3>
<p><ul>
<li>Fix a bug introduced in the previous release
that can cause a segfault while generating code
for complex WHERE clauses.</li>
<li>Allow floating point literals to begin or end with a decimal point.</li>
</ul></p>
<a name="version_3_2_3"></a>
<h3>2005 August 21 (3.2.3)</h3>
<p><ul>
<li>Added support for the CAST operator</li>
<li>Tcl interface allows BLOB values to be transferred to user-defined
functions</li>
<li>Added the "transaction" method to the Tcl interface</li>
<li>Allow the DEFAULT value of a column to call functions that have constant
operands</li>
<li>Added the ANALYZE command for gathering statistics on indices and
using those statistics when picking an index in the optimizer</li>
<li>Remove the limit (formerly 100) on the number of terms in the
WHERE clause</li>
<li>The right-hand side of the IN operator can now be a list of expressions
instead of just a list of constants</li>
<li>Rework the optimizer so that it is able to make better use of indices</li>
<li>The order of tables in a join is adjusted automatically to make
better use of indices</li>
<li>The IN operator is now a candidate for optimization even if the left-hand
side is not the left-most term of the index.  Multiple IN operators can be
used with the same index.</li>
<li>WHERE clause expressions using BETWEEN and OR are now candidates
for optimization</li>
<li>Added the "case_sensitive_like" pragma and the SQLITE_CASE_SENSITIVE_LIKE
compile-time option to set its default value to "on".</li>
<li>Use indices to help with GLOB expressions and LIKE expressions too
when the case_sensitive_like pragma is enabled</li>
<li>Added support for grave-accent quoting for compatibility with MySQL</li>
<li>Improved test coverage</li>
<li>Dozens of minor bug fixes</li>
</ul></p>
<a name="version_3_2_2"></a>
<h3>2005 June 13 (3.2.2)</h3>
<p><ul>
<li>Added the sqlite3_db_handle() API</li>
<li>Added the sqlite3_get_autocommit() API</li>
<li>Added a REGEXP operator to the parser.  There is no function to back
up this operator in the standard build but users can add their own using
sqlite3_create_function()</li>
<li>Speed improvements and library footprint reductions.</li>
<li>Fix byte alignment problems on 64-bit architectures.</li>
<li>Many, many minor bug fixes and documentation updates.</li>
</ul></p>
<a name="version_3_2_1"></a>
<h3>2005 March 29 (3.2.1)</h3>
<p><ul>
<li>Fix a memory allocation error in the new ADD COLUMN comment.</li>
<li>Documentation updates</li>
</ul></p>
<a name="version_3_2_0"></a>
<h3>2005 March 21 (3.2.0)</h3>
<p><ul>
<li>Added support for ALTER TABLE ADD COLUMN.</li>
<li>Added support for the "T" separator in ISO-8601 date/time strings.</li>
<li>Improved support for Cygwin.</li>
<li>Numerous bug fixes and documentation updates.</li>
</ul></p>
<a name="version_3_1_6"></a>
<h3>2005 March 16 (3.1.6)</h3>
<p><ul>
<li>Fix a bug that could cause database corruption when inserting
    record into tables with around 125 columns.</li>
<li>sqlite3_step() is now much more likely to invoke the busy handler
    and less likely to return SQLITE_BUSY.</li>
<li>Fix memory leaks that used to occur after a malloc() failure.</li>
</ul></p>
<a name="version_3_1_5"></a>
<h3>2005 March 11 (3.1.5)</h3>
<p><ul>
<li>The ioctl on OS-X to control syncing to disk is F_FULLFSYNC,
    not F_FULLSYNC.  The previous release had it wrong.</li>
</ul></p>
<a name="version_3_1_4"></a>
<h3>2005 March 10 (3.1.4)</h3>
<p><ul>
<li>Fix a bug in autovacuum that could cause database corruption if
a CREATE UNIQUE INDEX fails because of a constraint violation.
This problem only occurs if the new autovacuum feature introduced in
version 3.1 is turned on.</li>
<li>The F_FULLSYNC ioctl (currently only supported on OS-X) is disabled
if the synchronous pragma is set to something other than "full".</li>
<li>Add additional forward compatibility to the future version 3.2 database 
file format.</li>
<li>Fix a bug in WHERE clauses of the form (rowid<'2')</li>
<li>New SQLITE_OMIT_... compile-time options added</li>
<li>Updates to the man page</li>
<li>Remove the use of strcasecmp() from the shell</li>
<li>Windows DLL exports symbols Tclsqlite_Init and Sqlite_Init</li>
</ul></p>
<a name="version_3_1_3"></a>
<h3>2005 February 19 (3.1.3)</h3>
<p><ul>
<li>Fix a problem with VACUUM on databases from which tables containing
AUTOINCREMENT have been dropped.</li>
<li>Add forward compatibility to the future version 3.2 database file
format.</li>
<li>Documentation updates</li>
</ul></p>
<a name="version_3_1_2"></a>
<h3>2005 February 15 (3.1.2)</h3>
<p><ul>
<li>Fix a bug that can lead to database corruption if there are two
open connections to the same database and one connection does a VACUUM
and the second makes some change to the database.</li>
<li>Allow "?" parameters in the LIMIT clause.</li>
<li>Fix VACUUM so that it works with AUTOINCREMENT.</li>
<li>Fix a race condition in AUTOVACUUM that can lead to corrupt databases</li>
<li>Add a numeric version number to the sqlite3.h include file.</li>
<li>Other minor bug fixes and performance enhancements.</li>
</ul></p>
<a name="version_2_8_16"></a>
<h3>2005 February 15 (2.8.16)</h3>
<p><ul>
<li>Fix a bug that can lead to database corruption if there are two
open connections to the same database and one connection does a VACUUM
and the second makes some change to the database.</li>
<li>Correctly handle quoted names in CREATE INDEX statements.</li>
<li>Fix a naming conflict between sqlite.h and sqlite3.h.</li>
<li>Avoid excess heap usage when copying expressions.</li>
<li>Other minor bug fixes.</li>
</ul></p>
<h3>2005 February 1 (3.1.1 BETA)</h3>
<p><ul>
<li>Automatic caching of prepared statements in the TCL interface</li>
<li>ATTACH and DETACH as well as some other operations cause existing
    prepared statements to expire.</li>
<li>Numerious minor bug fixes</li>
</ul></p>
<h3>2005 January 21 (3.1.0 ALPHA)</h3>
<p><ul>
<li>Autovacuum support added</li>
<li>CURRENT_TIME, CURRENT_DATE, and CURRENT_TIMESTAMP added</li>
<li>Support for the EXISTS clause added.</li>
<li>Support for correlated subqueries added.</li>
<li>Added the ESCAPE clause on the LIKE operator.</li>
<li>Support for ALTER TABLE ... RENAME TABLE ... added</li>
<li>AUTOINCREMENT keyword supported on INTEGER PRIMARY KEY</li>
<li>Many SQLITE_OMIT_ macros inserts to omit features at compile-time
    and reduce the library footprint.</li>
<li>The REINDEX command was added.</li>
<li>The engine no longer consults the main table if it can get
    all the information it needs from an index.</li>
<li>Many nuisance bugs fixed.</li>
</ul></p>
<a name="version_3_0_8"></a>
<h3>2004 October 11 (3.0.8)</h3>
<p><ul>
<li>Add support for DEFERRED, IMMEDIATE, and EXCLUSIVE transactions.</li>
<li>Allow new user-defined functions to be created when there are
already one or more precompiled SQL statements.<li>
<li>Fix portability problems for Mingw/MSYS.</li>
<li>Fix a byte alignment problem on 64-bit Sparc machines.</li>
<li>Fix the ".import" command of the shell so that it ignores \r
characters at the end of lines.</li>
<li>The "csv" mode option in the shell puts strings inside double-quotes.</li>
<li>Fix typos in documentation.</li>
<li>Convert array constants in the code to have type "const".</li>
<li>Numerous code optimizations, specially optimizations designed to
make the code footprint smaller.</li>
</ul></p>