# # Run this script to generated a changes.html output file # puts { SQLite Change Log

Recent Changes To SQLite

This file provides a high-level summary of changes to SQLite. For more detail, refer the the checkin logs generated by CVS at http://cvs.hwaci.com:2080/sqlite/timeline.

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Added support for row triggers.

Added SQL-92 compliant handling of NULLs.

Add support for the full SQL-92 join syntax and LEFT OUTER JOINs.

Double-quoted strings interpreted as column names not text literals.

Parse (but do not implement) foreign keys.

Performance improvemenets in the parser, pager, and WHERE clause code generator.

Make the LIMIT clause work on subqueries. (ORDER BY still does not work, though.)

Added the "%Q" expansion to sqlite_*_printf().

Bug fixes too numerious to mention (see the change log).

Added logic to detect when the library API routines are called out of sequence.

Bug fix: Column names in the result set were not being generated correctly for some (rather complex) VIEWs. This could cause a segfault under certain circumstances.

Bug fix: Generate correct column headers when a compound SELECT is used as a subquery.

Added the sqlite_encode_binary() and sqlite_decode_binary() functions to the source tree. But they are not yet linked into the library.

Documentation updates.

Export the sqlite_changes() function from windows DLLs.

Bug fix: Do not attempt the subquery flattening optimization on queries that lack a FROM clause. To do so causes a segfault.

Fix a bug that was causing the precompiled binary of SQLITE.EXE to report "out of memory" under Windows 98.

Make sure VIEWs are created after their corresponding TABLEs in the output of the .dump command in the shell.

Speed improvements: Do not do synchronous updates on TEMP tables.

Many improvements and enhancements to the shell.

Make the GLOB and LIKE operators functions that can be overridden by a programmer. This allows, for example, the LIKE operator to be changed to be case sensitive.

Add the ability to put TABLE.* in the column list of a SELECT statement.

Permit SELECT statements without a FROM clause.

Added the last_insert_rowid() SQL function.

Do not count rows where the IGNORE conflict resultion occurs in the row count.

Make sure functions expressions in the VALUES clause of an INSERT are correct.

Added the sqlite_changes() API function to return the number of row that changed in the most recent operation.

Bug fix: Correctly handle terms in the WHERE clause of a join that do not contain a comparison operator.

Bug fix: Correctly handle functions that appear in the WHERE clause of a join.

When the PRAGMA vdbe_trace=ON is set, correctly print the P3 operand value when it is a pointer to a structure rather than a pointer to a string.

When inserting an explicit NULL into an INTEGER PRIMARY KEY, convert the NULL value into a unique key automatically.

Allow "VIEW" to be a column name

Added support for CASE expressions (patch from Dan Kennedy)

Added RPMS to the delivery (patches from Doug Henry)

Fix typos in the documentation

Cut over configuration management to a new CVS repository with its own CVSTrac bug tracking system.

Fix a bug in SELECT that occurs when a compound SELECT is used as a subquery in the FROM of a SELECT.

The sqlite_get_table() function now returns an error if you give it two or more SELECTs that return different numbers of columns.

Bug fix: Fix an assertion failure that occurred when ROWID was a column in a SELECT statement on a view.

Bug fix: Fix an uninitialized variable in the VDBE that would could an assert failure.

Make the os.h header file more robust in detecting when the compile is for windows and when it is for unix.

Using an unnamed subquery in a FROM clause would cause a segfault.

The parser now insists on seeing a semicolon or the end of input before executing a statement. This avoids an accidental disaster if the WHERE keyword is misspelled in an UPDATE or DELETE statement.

Change the name of the sanity_check PRAGMA to integrity_check and make it available in all compiles.

SELECT min() or max() of an indexed column with no WHERE or GROUP BY clause is handled as a special case which avoids a complete table scan.

Automatically generated ROWIDs are now sequential.

Do not allow dot-commands of the command-line shell to occur in the middle of a real SQL command.

Modifications to the "lemon" parser generator so that the parser tables are 4 times smaller.

Added support for user-defined functions implemented in C.

Added support for new functions: coalesce(), lower(), upper(), and random()

Added support for VIEWs.

Added the subquery flattening optimizer.

Modified the B-Tree and Pager modules so that disk pages that do not contain real data (free pages) are not journalled and are not written from memory back to the disk when they change. This does not impact database integrity, since the pages contain no real data, but it does make large INSERT operations about 2.5 times faster and large DELETEs about 5 times faster.

Made the CACHE_SIZE pragma persistent

Added the SYNCHRONOUS pragma

Fixed a bug that was causing updates to fail inside of transactions when the database contained a temporary table.

Allow identifiers to be quoted in square brackets, for compatibility with MS-Access.

Added support for sub-queries in the FROM clause of a SELECT.

More efficient implementation of sqliteFileExists() under Windows. (by Joel Luscy)

The VALUES clause of an INSERT can now contain expressions, including scalar SELECT clauses.

Added support for CREATE TABLE AS SELECT

Bug fix: Creating and dropping a table all within a single transaction was not working.

Bug fix: There was an incorrect assert() in pager.c. The real code was all correct (as far as is known) so everything should work OK if you compile with -DNDEBUG=1. When asserts are not disabled, there could be a fault.

Bug fix: An assertion was failing if "PRAGMA full_column_names=ON;" was set and you did a query that used a rowid, like this: "SELECT rowid, * FROM ...".

Fix a serious bug in the INSERT command which was causing data to go into the wrong columns if the data source was a SELECT and the INSERT clauses specified its columns in some order other than the default.

Added the ability to resolve constraint conflicts is ways other than an abort and rollback. See the documentation on the "ON CONFLICT" clause for details.

Temporary files are now automatically deleted by the operating system when closed. There are no more dangling temporary files on a program crash. (If the OS crashes, fsck will delete the file after reboot under Unix. I do not know what happens under Windows.)

NOT NULL constraints are honored.

The COPY command puts NULLs in columns whose data is '\N'.

In the COPY command, backslash can now be used to escape a newline.

Added the SANITY_CHECK pragma.

Important bug fix: the IN operator was not working if either the left-hand or right-hand side was derived from an INTEGER PRIMARY KEY.

Do not escape the backslash '\' character in the output of the sqlite command-line access program.

The label to the right of an AS in the column list of a SELECT can now be used as part of an expression in the WHERE, ORDER BY, GROUP BY, and/or HAVING clauses.

Fix a bug in the -separator command-line option to the sqlite command.

Fix a problem with the sort order when comparing upper-case strings against characters greater than 'Z' but less than 'a'.

Report an error if an ORDER BY or GROUP BY expression is constant.

Fix warning messages in VC++ 7.0. (Patches from nicolas352001)

Make the library thread-safe. (The code is there and appears to work but has not been stressed.)

Added the new sqlite_last_insert_rowid() API function.

Bug fix: An assertion was failing when a temporary table with an index had the same name as a permanent table created by a separate process.

Bug fix: Updates to tables containing an INTEGER PRIMARY KEY and an index could fail.

Bug fix: An attempt to delete a single row of a table with a WHERE clause of "ROWID=x" when no such rowid exists was causing an error.

Bug fix: Passing in a NULL as the 3rd parameter to sqlite_open() would sometimes cause a coredump.

Bug fix: DROP TABLE followed by a CREATE TABLE with the same name all within a single transaction was causing a coredump.

Makefile updates from A. Rottmann

Columns of type INTEGER PRIMARY KEY are actually used as the primary key in underlying B-Tree representation of the table.

Several obscure, unrelated bugs were found and fixed while implemented the integer primary key change of the previous bullet.

Added the ability to specify "*" as part of a larger column list in the result section of a SELECT statement. For example: "SELECT rowid, * FROM table1;".

Updates to comments and documentation.

Fix a bug in CREATE TEMPORARY TABLE which was causing the table to be initially allocated in the main database file instead of in the separate temporary file. This bug could cause the library to suffer an assertion failure and it could cause "page leaks" in the main database file.

Fix a bug in the b-tree subsystem that could sometimes cause the first row of a table to be repeated during a database scan.

Fix the locking mechanism yet again to prevent sqlite_exec() from returning SQLITE_PROTOCOL unnecessarily. This time the bug was a race condition in the locking code. This change effects both POSIX and Windows users.

Fix for another problem (unrelated to the one fixed in 2.1.4) that sometimes causes sqlite_exec() to return SQLITE_PROTOCOL unnecessarily. This time the bug was in the POSIX locking code and should not effect windows users.

Sometimes sqlite_exec() would return SQLITE_PROTOCOL when it should have returned SQLITE_BUSY.

The fix to the previous bug uncovered a deadlock which was also fixed.

Add the ability to put a single .command in the second argument of the sqlite shell

Updates to the FAQ

Fix the behavior of comparison operators (ex: "<", "==", etc.) so that they are consistent with the order of entries in an index.

Correct handling of integers in SQL expressions that are larger than what can be represented by the machine integer.

Changes to support 64-bit architectures.

Fix a bug in the locking protocol.

Fix a bug that could (rarely) cause the database to become unreadable after a DROP TABLE due to corruption to the SQLITE_MASTER table.

Change the code so that version 2.1.1 databases that were rendered unreadable by the above bug can be read by this version of the library even though the SQLITE_MASTER table is (slightly) corrupted.

Bug fix: Sometimes arbirary strings were passed to the callback function when the actual value of a column was NULL.

Change the format of data records so that records up to 16MB in size can be stored.

Change the format of indices to allow for better query optimization.

Implement the "LIMIT ... OFFSET ..." clause on SELECT statements.

Made selected parameters in API functions const. This should be fully backwards compatible.

Documentation updates

Simplify the design of the VDBE by restricting the number of sorters and lists to 1. In practice, no more than one sorter and one list was ever used anyhow.

Any UTF-8 character or ISO8859 character can be used as part of an identifier.

Patches from Christian Werner to improve ODBC compatibility and to fix a bug in the round() function.

Plug some memory leaks that use to occur if malloc() failed. We have been and continue to be memory leak free as long as malloc() works.

Changes to some test scripts so that they work on Windows in addition to Unix.

Added the EMPTY_RESULT_CALLBACKS pragma

Support for UTF-8 and ISO8859 characters in column and table names.

Bug fix: Compute correct table names with the FULL_COLUMN_NAMES pragma is turned on.

Added the COUNT_CHANGES pragma.

Changes to the FULL_COLUMN_NAMES pragma to help out the ODBC driver.

Bug fix: "SELECT count(*)" was returning NULL for empty tables. Now it returns 0.

Bug fix: an abscure and relatively harmless bug was causing one of the tests to fail when gcc optimizations are turned on. This release fixes the problem.

Bug fix: the sqlite_busy_timeout() function was delaying 1000 times too long before failing.

Bug fix: an assertion was failing if the disk holding the database file became full or stopped accepting writes for some other reason. New tests were added to detect similar problems in the future.

Added new operators: & (bitwise-and) | (bitwise-or), ~ (ones-complement), << (shift left), >> (shift right).

Added new functions: round() and abs().

Fix two bugs in the locking protocol. (One was masking the other.)

Removed some unused "#include " that were causing problems for VC++.

Fixed sqlite.h so that it is usable from C++

Added the FULL_COLUMN_NAMES pragma. When set to "ON", the names of columns are reported back as TABLE.COLUMN instead of just COLUMN.

Added the TABLE_INFO() and INDEX_INFO() pragmas to help support the ODBC interface.

Added support for TEMPORARY tables and indices.

Remove some C++ style comments from btree.c so that it will compile using compilers other than gcc.

The ".dump" output from the shell does not work if there are embedded newlines anywhere in the data. This is an old bug that was carried forward from version 1.0. To fix it, the ".dump" output no longer uses the COPY command. It instead generates INSERT statements.

Extend the expression syntax to support "expr NOT NULL" (with a space between the "NOT" and the "NULL") in addition to "expr NOTNULL" (with no space).

Automatically build binaries for Linux and Windows and put them on the website.

Incorporate makefile patches form A. Rottmann to use LIBTOOL

SQLite now honors the UNIQUE keyword in CREATE UNIQUE INDEX. Primary keys are required to be unique.

File format changed back to what it was for alpha-1

Fixes to the rollback and locking behavior

Initial release of version 2.0. The idea of renaming the library to "SQLus" was abandoned in favor of keeping the "SQLite" name and bumping the major version number.

The pager and btree subsystems added back. They are now the only available backend.

The Dbbe abstraction and the GDBM and memory drivers were removed.

Pager and btree subsystems removed. These will be used in a follow-on SQL server library named "SQLus".

Add the ability to use quoted strings as table and column names in expressions.

Pager subsystem added but not yet used.

More robust handling of out-of-memory errors.

New tests added to the test suite.

Remove the sqlite_encoding TCL variable that was introduced in the previous version.

Add options -encoding and -tcl-uses-utf to the sqlite TCL command.

Add tests to make sure that tclsqlite was compiled using Tcl header files and libraries that match.

The library now assumes data is stored as UTF-8 if the --enable-utf8 option is given to configure. The default behavior is to assume iso8859-x, as it has always done. This only makes a difference for LIKE and GLOB operators and the LENGTH and SUBSTR functions.

If the library is not configured for UTF-8 and the Tcl library is one of the newer ones that uses UTF-8 internally, then a conversion from UTF-8 to iso8859 and back again is done inside the TCL interface.

Added limited support for transactions. At this point, transactions will do table locking on the GDBM backend. There is no support (yet) for rollback or atomic commit.

Added special column names ROWID, OID, and _ROWID_ that refer to the unique random integer key associated with every row of every table.

Additional tests added to the regression suite to cover the new ROWID feature and the TCL interface bugs mentioned below.

Changes to the "lemon" parser generator to help it work better when compiled using MSVC.

Bug fixes in the TCL interface identified by Oleg Oleinick.

When doing DELETE and UPDATE, the library used to write the record numbers of records to be deleted or updated into a temporary file. This is changed so that the record numbers are held in memory.

The DELETE command without a WHILE clause just removes the database files from the disk, rather than going through and deleting record by record.

A serious bug fixed on Windows. Windows users should upgrade. No impact to Unix.

Modify the test scripts to identify tests that depend on system load and processor speed and to warn the user that a failure of one of those (rare) tests does not necessarily mean the library is malfunctioning. No changes to code.

Fix a bug which was causing the UPDATE command to fail on systems where "malloc(0)" returns NULL. The problem does not appear Windows, Linux, or HPUX but does cause the library to fail on QNX.

An unrelated (and minor) bug from Mark Muranwski fixed. The algorithm for figuring out where to put temporary files for a "memory:" database was not working quite right.

The previous fix was not quite right. This one seems to work better.

The UPDATE statement was not working when the WHERE clause contained some terms that could be satisfied using indices and other terms that could not. Fixed.

Merge development changes into the main trunk. Future work toward using a BTree file structure will use a separate CVS source tree. This CVS tree will continue to support the GDBM version of SQLite only.

Fix a strange (but valid) C declaration that was causing problems for QNX. No logical changes.

Print the offending SQL statement when an error occurs.

Do not require commas between constraints in CREATE TABLE statements.

Added the "-echo" option to the shell.

Changes to comments.

Rewrote sqlite_complete() to make it faster.

Minor tweaks to other code to make it run a little faster.

Added new tests for sqlite_complete() and for memory leaks.

Documentation updates. Mostly fixing of typos and spelling errors.

Documentation updates

Some sanity checking code was removed from the inner loop of vdbe.c to help the library to run a little faster. The code is only removed if you compile with -DNDEBUG.

Added a "memory:" backend driver that stores its database in an in-memory hash table.

Break out the GDBM driver into a separate file in anticipation to added new drivers.

Allow the name of a database to be prefixed by the driver type. For now, the only driver type is "gdbm:".

Fixed an off-by-one error that was causing a coredump in the '%q' format directive of the new sqlite_..._printf() routines.

Added the sqlite_interrupt() interface.

In the shell, sqlite_interrupt() is invoked when the user presses Control-C

Fixed some instances where sqlite_exec() was returning the wrong error code.

Added notes on how to compile for Windows95/98.

Removed a few variables that were not being used. Etc.

Added the sqlite_..._printf() interface routines.

Modified the sqlite shell program to use the new interface routines.

Modified the sqlite shell program to print the schema for the built-in SQLITE_MASTER table, if explicitly requested.

Begin writing documentation on the TCL interface.

Added the sqlite_get_table() API

Updated the documentation for due to the above change.

Modified the sqlite shell to make use of the new sqlite_get_table() API in order to print a list of tables in multiple columns, similar to the way "ls" prints filenames.

Modified the sqlite shell to print a semicolon at the end of each CREATE statement in the output of the ".schema" command.

Change the tclsqlite "eval" method to return a list of results if no callback script is specified.

Change tclsqlite.c to use the Tcl_Obj interface

Add tclsqlite.c to the libsqlite.a library

Changed the print format for floating point values from "%g" to "%.15g".

Changed the comparison function so that numbers in exponential notation (ex: 1.234e+05) sort in numerical order.

Added functions length() and substr().

Fix a bug in the sqlite shell program that was causing a coredump when the output mode was "column" and the first row of data contained a NULL.

In the sqlite shell, print the "Database opened READ ONLY" message to stderr instead of stdout.

In the sqlite shell, now print the version number on initial startup.

Add the sqlite_version[] string constant to the library

Makefile updates

Bug fix: incorrect VDBE code was being generated for the following circumstance: a query on an indexed table containing a WHERE clause with an IN operator that had a subquery on its right-hand side.

Fix a bug in the configure script.

Minor revisions to the website.

Change the sqlite program so that it can read databases for which it lacks write permission. (It used to refuse all access if it could not write.)

Treat carriage returns as white space.

Added pattern matching to the ".table" command in the "sqlite" command shell.

Documentation updates

Added "busy" and "timeout" methods to the Tcl interface

File format version number was being stored in sqlite_master.tcl multiple times. This was harmless, but unnecessary. It is now fixed.

The file format for indices was changed slightly in order to work around an inefficiency that can sometimes come up with GDBM when there are large indices having many entries with the same key. ** Incompatible Change **

The parser's stack was overflowing on a very long UPDATE statement. This is now fixed.

Finish the VDBE tutorial.

Added documentation on compiling to WindowsNT.

Fix a configuration program for WindowsNT.

Fix a configuration problem for HPUX.

Better labels on column names of the result.

Added the sqlite_busy_handler() and sqlite_busy_timeout() interface.

Begin writing the VDBE tutorial.

Clean up comments and variable names. Changes to documentation. No functional changes to the code.

Column names in UPDATE statements were case sensitive. This mistake has now been fixed.

Added the concatenate string operator (||)

Added the fcnt() function to the SQL interpreter. The fcnt() function returns the number of database "Fetch" operations that have occurred. This function is designed for use in test scripts to verify that queries are efficient and appropriately optimized. Fcnt() has no other useful purpose, as far as I know.

Added a bunch more tests that take advantage of the new fcnt() function. The new tests did not uncover any new problems.

Added lots of new test cases

Fix a few bugs discovered while adding test cases

Begin adding lots of new documentation

Added compound select operators: UNION, UNION ALL, INTERSECT, and EXCEPT

Added support for using (SELECT ...) within expressions

Added support for IN and BETWEEN operators

Added support for GROUP BY and HAVING

NULL values are now reported to the callback as a NULL pointer rather than an empty string.

Added support for default values on columns of a table.

Improved test coverage. Fixed a few obscure bugs found by the improved tests.

All database files to be modified by an UPDATE, INSERT or DELETE are now locked before any changes are made to any files. This makes it safe (I think) to access the same database simultaneously from multiple processes.

The code appears stable so we are now calling it "beta".

Better support for file locking so that two or more processes (or threads) can access the same database simultaneously. More work needed in this area, though.

Added support for aggregate functions (Ex: COUNT(*), MIN(...)) to the SELECT statement.

Added support for SELECT DISTINCT ...

Added the LIKE operator.

Added a GLOB operator: similar to LIKE but it uses Unix shell globbing wildcards instead of the '%' and '_' wildcards of SQL.

Added the COPY command patterned after PostgreSQL so that SQLite can now read the output of the pg_dump database dump utility of PostgreSQL.

Added a VACUUM command that that calls the gdbm_reorganize() function on the underlying database files.

And many, many bug fixes...

Initial Public Release of Alpha code

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