changes.html

sqlite的帮助文档

</ul></p><a name="version_3_3_16"></a>
<h3>2007 April 18 (3.3.16)</h3><p><ul>
<li>Fix a bug that caused VACUUM to fail if NULLs appeared in a
    UNIQUE column.</li>
<li>Reinstate performance improvements that were added in
    <a href="#version_3_3_14">Version 3.3.14</a>
    but regressed in <a href="#version_3_3_15">Version 3.3.15</a>.</li>
<li>Fix problems with the handling of ORDER BY expressions on
    compound SELECT statements in subqueries.</li>
<li>Fix a potential segfault when destroying locks on WinCE in
    a multi-threaded environment.</li>
<li>Documentation updates.</li>
</ul></p><a name="version_3_3_15"></a>
<h3>2007 April 9 (3.3.15)</h3><p><ul>
<li>Fix a bug introduced in 3.3.14 that caused a rollback of
    CREATE TEMP TABLE to leave the database connection wedged.</li>
<li>Fix a bug that caused an extra NULL row to be returned when
    a descending query was interrupted by a change to the database.</li>
<li>The FOR EACH STATEMENT clause on a trigger now causes a syntax
    error.  It used to be silently ignored.</li>
<li>Fix an obscure and relatively harmless problem that might have caused
    a resource leak following an I/O error.</li>
<li>Many improvements to the test suite.  Test coverage now exceeded 98%</li>
</ul></p><a name="version_3_3_14"></a>
<h3>2007 April 2 (3.3.14)</h3><p><ul>
<li>Fix a bug (<a href="http://www.sqlite.org/cvstrac/tktview?tn=2273">ticket #2273</a>)
    that could cause a segfault when the IN operator
    is used one one term of a two-column index and the right-hand side of
    the IN operator contains a NULL.</li>
<li>Added a new OS interface method for determining the sector size
    of underlying media:  sqlite3OsSectorSize().</li>
<li>A new algorithm for statements of the form
    INSERT INTO <i>table1</i> SELECT * FROM <i>table2</i>
    is faster and reduces fragmentation.  VACUUM uses statements of
    this form and thus runs faster and defragments better.</li>
<li>Performance enhancements through reductions in disk I/O:
<ul>
<li>Do not read the last page of an overflow chain when
    deleting the row - just add that page to the freelist.</li>
<li>Do not store pages being deleted in the 
    rollback journal.</li>
<li>Do not read in the (meaningless) content of
    pages extracted from the freelist.</li>
<li>Do not flush the page cache (and thus avoiding
    a cache refill) unless another process changes the underlying
    database file.</li>
<li>Truncate rather than delete the rollback journal when committing
    a transaction in exclusive access mode, or when committing the TEMP
    database.</li>
</ul></li>
<li>Added support for exclusive access mode using
    <a href="pragma.html#pragma_locking_mode">
    "PRAGMA locking_mode=EXCLUSIVE"</a></li>
<li>Use heap space instead of stack space for large buffers in the
    pager - useful on embedded platforms with  stack-space
    limitations.</li>
<li>Add a makefile target "sqlite3.c" that builds an amalgamation containing
    the core SQLite library C code in a single file.</li>
<li>Get the library working correctly when compiled 
    with GCC option "-fstrict-aliasing".</li>
<li>Removed the vestigal SQLITE_PROTOCOL error.</li>
<li>Improvements to test coverage, other minor bugs fixed,
    memory leaks plugged,
    code refactored and/or recommented in places for easier reading.</li>
</ul></p><a name="version_3_3_13"></a>
<h3>2007 February 13 (3.3.13)</h3><p><ul>
<li>Add a "fragmentation" measurement in the output of sqlite3_analyzer.</li>
<li>Add the COLLATE operator used to explicitly set the collating sequence
used by an expression.  This feature is considered experimental pending
additional testing.</li>
<li>Allow up to 64 tables in a join - the old limit was 32.</li>
<li>Added two new experimental functions:
<a href="lang_expr.html#randomblobFunc">randomBlob()</a> and
<a href="lang_expr.html#hexFunc">hex()</a>.
Their intended use is to facilitate generating 
<a href="http://en.wikipedia.org/wiki/UUID">UUIDs</a>.
</li>
<li>Fix a problem where
<a href="pragma.html#pragma_count_changes">PRAGMA count_changes</a> was
causing incorrect results for updates on tables with triggers</li>
<li>Fix a bug in the ORDER BY clause optimizer for joins where the
left-most table in the join is constrained by a UNIQUE index.</li>
<li>Fixed a bug in the "copy" method of the TCL interface.</li>
<li>Bug fixes in fts1 and fts2 modules.</li>
</ul></p><a name="version_3_3_12"></a>
<h3>2007 January 27 (3.3.12)</h3><p><ul>
<li>Fix another bug in the IS NULL optimization that was added in
version 3.3.9.</li>
<li>Fix a assertion fault that occurred on deeply nested views.</li>
<li>Limit the amount of output that
<a href="pragma.html#pragma_integrity_check">PRAGMA integrity_check</a>
generates.</li>
<li>Minor syntactic changes to support a wider variety of compilers.</li>
</ul></p><a name="version_3_3_11"></a>
<h3>2007 January 22 (3.3.11)</h3><p><ul>
<li>Fix another bug in the implementation of the new 
<a href="c3ref/prepare.html">sqlite3_prepare_v2()</a> API.
We'll get it right eventually...</li>
<li>Fix a bug in the IS NULL optimization that was added in version 3.3.9 -
the bug was causing incorrect results on certain LEFT JOINs that included
in the WHERE clause an IS NULL constraint for the right table of the
LEFT JOIN.</li>
<li>Make AreFileApisANSI() a no-op macro in winCE since winCE does not
support this function.</li>
</ul></p><a name="version_3_3_10"></a>
<h3>2007 January 9 (3.3.10)</h3><p><ul>
<li>Fix bugs in the implementation of the new 
<a href="c3ref/prepare.html">sqlite3_prepare_v2()</a> API
that can lead to segfaults.</li>
<li>Fix 1-second round-off errors in the 
<a href="http://www.sqlite.org/cvstrac/wiki?p=DateAndTimeFunctions">
strftime()</a> function</li>
<li>Enhance the Windows OS layer to provide detailed error codes</li>
<li>Work around a win2k problem so that SQLite can use single-character
database file names</li>
<li>The
<a href="pragma.html#pragma_user_version">user_version</a> and
<a href="pragma.html#pragma_schema_version">schema_version</a> pragmas 
correctly set their column names in the result set</li>
<li>Documentation updates</li>
</ul></p><a name="version_3_3_9"></a>
<h3>2007 January 4 (3.3.9)</h3><p><ul>
<li>Fix bugs in pager.c that could lead to database corruption if two
processes both try to recover a hot journal at the same instant</li>
<li>Added the <a href="c3ref/prepare.html">sqlite3_prepare_v2()</a>
API.</li>
<li>Fixed the ".dump" command in the command-line shell to show
indices, triggers and views again.</li>
<li>Change the table_info pragma so that it returns NULL for the default
value if there is no default value</li>
<li>Support for non-ASCII characters in win95 filenames</li>
<li>Query optimizer enhancements:
<ul>
<li>Optimizer does a better job of using indices to satisfy ORDER BY
clauses that sort on the integer primary key</li>
<li>Use an index to satisfy an IS NULL operator in the WHERE clause</li>
<li>Fix a bug that was causing the optimizer to miss an OR optimization
opportunity</li>
<li>The optimizer has more freedom to reorder tables in the FROM clause
even in there are LEFT joins.</li>
</ul>
<li>Extension loading supported added to winCE</li>
<li>Allow constraint names on the DEFAULT clause in a table definition</li>
<li>Added the ".bail" command to the command-line shell</li>
<li>Make CSV (comma separate value) output from the command-line shell
more closely aligned to accepted practice</li>
<li>Experimental FTS2 module added</li>
<li>Use sqlite3_mprintf() instead of strdup() to avoid libc dependencies</li>
<li>VACUUM uses a temporary file in the official TEMP folder, not in the
same directory as the original database</li>
<li>The prefix on temporary filenames on Windows is changed from "sqlite"
to "etilqs".</li>
</ul></p><a name="version_3_3_8"></a>
<h3>2006 October 9 (3.3.8)</h3><p><ul>
<li>Support for full text search using the
<a href="http://www.sqlite.org/cvstrac/wiki?p=FullTextIndex">FTS1 module</a>
(beta)</li>
<li>Added OS-X locking patches (beta - disabled by default)</li>
<li>Introduce extended error codes and add error codes for various
kinds of I/O errors.</li>
<li>Added support for IF EXISTS on CREATE/DROP TRIGGER/VIEW</li>
<li>Fix the regression test suite so that it works with Tcl8.5</li>
<li>Enhance sqlite3_set_authorizer() to provide notification of calls to
    SQL functions.</li>
<li>Added experimental API:  sqlite3_auto_extension()</li>
<li>Various minor bug fixes</li>
</ul></p><a name="version_3_3_7"></a>
<h3>2006 August 12 (3.3.7)</h3><p><ul>
<li>Added support for
<a href="http://www.sqlite.org/cvstrac/wiki?p=VirtualTables">virtual tables</a>
(beta)</li>
<li>Added support for 
<a href="http://www.sqlite.org/cvstrac/wiki?p=LoadableExtensions">
dynamically loaded extensions</a> (beta)</li>
<li>The 
<a href="c3ref/interrupt.html">sqlite3_interrupt()</a>
routine can be called for a different thread</li>
<li>Added the <a href="lang_expr.html#match">MATCH</a> operator.</li>
<li>The default file format is now 1.  
</ul></p><a name="version_3_3_6"></a>
<h3>2006 June 6 (3.3.6)</h3><p><ul>
<li>Plays better with virus scanners on Windows</li>
<li>Faster :memory: databases</li>
<li>Fix an obscure segfault in UTF-8 to UTF-16 conversions</li>
<li>Added driver for OS/2</li>
<li>Correct column meta-information returned for aggregate queries</li>
<li>Enhanced output from EXPLAIN QUERY PLAN</li>
<li>LIMIT 0 now works on subqueries</li>
<li>Bug fixes and performance enhancements in the query optimizer</li>
<li>Correctly handle NULL filenames in ATTACH and DETACH</li>
<li>Inproved syntax error messages in the parser</li>
<li>Fix type coercion rules for the IN operator</li>
</ul></p><a name="version_3_3_5"></a>
<h3>2006 April 5 (3.3.5)</h3><p><ul>
<li>CHECK constraints use conflict resolution algorithms correctly.</li>
<li>The SUM() function throws an error on integer overflow.</li>
<li>Choose the column names in a compound query from the left-most SELECT
    instead of the right-most.</li>
<li>The sqlite3_create_collation() function
    honors the SQLITE_UTF16_ALIGNED flag.</li>
<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>