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KInterbasDB Changelog

Version 3.3

New Features

  • It is now possible to use multiple transactions simultaneously on a single kinterbasdb.Connection. See discussion: http://sourceforge.net/forum/forum.php?thread_id=1597658&forum_id=30917

  • If a unicode object is passed as the SQL statement to any of

    • kinterbasdb.create_database
    • Connection.execute_immediate
    • Cursor.prep
    • Cursor.execute

    KInterbasDB will attempt to encode it to the character set of file system (in the case of kinterbasdb.create_database), or to the character set of the connection, in the other cases. Previously, only unicode objects that could be encoded to ASCII were accepted.

  • Documentation was extended and completely redone using reStructured text and Sphinx (http://sphinx.pocoo.org)

Backward-incompatibilities

  • Default type conversion setting was changed to type_conv=200. Applications that doesn’t call kinterbasdb.init() and rely on Python older than 2.4 and/or mx.DateTime and/or explicit unicode conversion must call kinterbasdb.init() with type_conv=1 as first thing after kinterbasdb import. Applications that explicitly call kinterbasdb.init() doesn’t need to be changed at all.

    Details about new default setting are described in Parameter Conversion section Deferred Loading of Dynamic Type Translators of KInterbasDB documentation.

Version 3.2.2

Bug Fixes

  • Fixed bug with wrong Transaction Parameter Block structure. It surfaces with Firebird 2.1 that’s more strict about TPB correctness.
  • Fixed bug with Services under Firebird 2.1.

Version 3.2.1

Bug Fixes

Version 3.2

Bug Fixes

  • At concurrency_level 1, it was possible for a deadlock to occur if KInterbasDB simultaneously raised an exception in one thread while executing a SQL statement in another. This problem did not affect concurrency_level 2.

    Thanks to Atsuo Ishimoto for reporting this bug.

  • The official implementation of the automagic TEXT_UNICODE type translator (in the kinterbasdb.typeconv_text_unicode module) was missing support for the new character sets introduced in Firebird 2.0 (namely, the corrected version of UTF8, plus KOI8-R, KOI8-U, and WIN1258).

    Thanks to Oleg Deribas for bringing this to my attention.

Version 3.2rc1

Bug Fixes

New Features

  • KInterbasDB now stores and retrieves the undocumented sub-second component of TIME and TIMESTAMP fields.

    Thanks to Petr Jakes and Helen Borrie for bringing the availability of the sub-second data to my attention.

  • Passing None to Cursor.execute (instead of a SQL string or a PreparedStatement) now executes the most recently prepared/executed statement, if any. This can enhance convenience because it frees the client programmer from the responsibility of separately tracking the most recent statement in order to execute it again.

    Thanks to Igor Youdytsky for suggesting this feature.

  • PreparedStatements now have a read-only ‘description’ property that contains a Python DB API 2.0 description sequence of the same format as Cursor.description.

    Thanks to Alexandr Zamaraev for suggesting this feature. For more info, see: http://kinterbasdb.sf.net/dist_docs/usage.html#PreparedStatement_description

  • The following query and resolution methods for limbo transactions have been added to the kinterbasdb.services.Connection class: getLimboTransactionIDs, commitLimboTransaction, rollbackLimboTransaction.

Backward-incompatibilities

  • Dynamic Type Translators for TIME and TIMESTAMP fields must now accomodate an additional tuple element: an integer which represents microseconds. The official TIME and TIMESTAMP type translators in typeconv_datetime_naked.py, typeconv_datetime_stdlib.py, and typeconv_datetime_mx.py have been updated, and can be used as a guide.

Version 3.2b1

Bug Fixes

  • Previously, if KInterbasDB detected that the field to which a NULL value was bound was defined as NOT NULL, KInterbasDB itself immediately raised an exception. This caused problems for fields defined as NOT NULL but populated by BEFORE triggers, so KInterbasDB now submits the illegal NULL and allows the database engine to make the decision.
  • Fixed an obscure memory leak in Connection.drop_database.
  • Fixed a few more compatibility problems with Interbase 7.x.
  • kinterbasdb.Cursor can again be used as a base class for user-defined subclasses. This capability had been removed in KInterbasDB 3.2a1.

New Features

  • Connection timeouts: KInterbasDB connections can now be asked to time out after a specified period of inactivity. This feature is not supported by the Firebird C API, so it is implemented entirely at the KInterbasDB level. For more info, see: http://kinterbasdb.sf.net/dist_docs/usage.html#adv_ct

  • Added a TPB class to assist with the construction of complex Transaction Parameter Buffers.

    This feature has not yet been documented. In the meantime, you can find example code in the test_transactions.py module of the KInterbasDB test suite: http://kinterbasdb.sf.net/test-suite/releases/

  • Added methods Connection.transaction_info and Connection.trans_info. transaction_info is a thin wrapper around the C function isc_transaction_info, while trans_info is a Pythonic wrapper around transaction_info.

    This feature has not yet been documented. In the meantime, you can find example code in the test_services.py module of the KInterbasDB test suite: http://kinterbasdb.sf.net/test-suite/releases/

  • Exposed the Firebird header constant FB_API_VER as kinterbasdb.FB_API_VER. This integer represents the version of Firebird against which KInterbasDB was compiled, as follows:

    • Any version of Interbase, or Firebird 1.0.x: 10
    • Firebird 1.5.x: 15
    • Firebird 2.0.x: 20

  • KInterbasDB now raises a kinterbasdb.TransactionConflict exception (instead of the rather generic ProgrammingError) when it receives a server-side transaction conflict notification. This makes it easier for the client programmer to detect and resolve deadlocks.

    TransactionConflict is a subclass of kinterbasdb.OperationalError.

Backward-incompatibilities

  • Client programs that encounter transaction conflicts in routine operation, and which contain logic to deal with this type of exception specifically (on the basis of the payload of the ProgrammingError) should be updated to use:

    try:
  ...
except kinterbasdb.TransactionConflict:
  ...

    instead.

    For more info, see the last item under “New Features” above.

Version 3.2a1

New Features

Bug Fixes

  • KInterbasDB should now compile and run out of the box with Interbase 7.x. DSR doesn’t have that version of Interbase, however, so KInterbasDB is not actually tested with it.

Backward-incompatibilities

  • KInterbasDB 3.2 has dropped support for Python versions earlier than 2.3, and (officially) supports only Firebird 1.0 and later. However, Interbase 7.x support has been considerably enhanced, so it could be said that Interbase is “unofficially” supported.

  • Most Python classes in KInterbasDB have become new-style, for symmetry with the new-style C classes added in 3.2. Notably, kinterbasdb.Cursor is now a new-style class written in pure C.

    Impact rating: Low (There is practically no reason for a client program to access the affected KInterbasDB classes in such a way that this change would matter.)

  • Previously, the “infinite timeout value” for EventConduit.wait was 0.0. The choice of that value was a terrible mistake, because attempting to specify an extremely short timeout with a value such as 0.000000000000001 in fact created an infinite timeout. The new “infinite timeout value” is -1.0.

    Impact rating: Low-Medium (The Usage Guide for KInterbasDB 3.1 specified that “The default timeout is infinite.”, but it did not guarantee a particular value. Client programs that use both events and event timeouts should be checked, however.)

Version 3.1.3

Bug Fixes

Version 3.1.2

Bug Fixes

  • Attempting to apply dynamic type translation settings dictionaries that had non-string keys caused a segfault under some some circumstances.
  • kinterbasdb’s Services API infrastructure parsed integer results from the engine as recommended by the IB 6 API Guide, but this was inappropriate on non-Windows x86-64, and could cause invalid memory access.
  • Input handling of INTEGER ARRAY fields did not work correctly on non-Windows x86-64.
  • Overridding a connection’s dynamic type translation settings for a particular slot with the “naked” translator by passing None as the translator to Cursor.set_type_trans_[in|out] did not work.
  • The FIXED dynamic type translation slot was not handled properly on dialect 1 connections (dialect 1 databases store NUMERIC/DECIMAL values with precisions 10-18 internally as floating point).
  • Documentation bug: The “Using KInterbasDB with Embedded Firebird” section of the Usage Guide stated that the Services API did not work with the embedded server architecture. That was written when Firebird 1.5 was in alpha; the Services API does work with embedded Firebird 1.5.2.

Version 3.1.1

Bug Fixes

  • kinterbasdb.init(type_conv=100|200) didn’t work under Python 2.4. Late in the Python 2.4 development cycle, additional constraints were introduced in Python’s funcobject.c that defeated kinterbasdb’s attempts to manipulate the ‘func_code’ attribute of some functions during the execution of kinterbasdb.init.
  • C type ConnectionType’s destructor was called directly (rather than as a result of DECREF) if an error arose in kinterbasdb.connect or kinterbasdb.create_database. This triggered a refcount assertion in debug builds of Python.
  • Fixed a reference count leak in the C layer’s central exception-raising function.
  • Fixed some potential memory handling problems in exceptional situations in the event handling code.
  • A trivial problem prevented kinterbasdb 3.1 from compiling with the prereleases of Firebird 2.0.

New Features

  • In typeconv_text_unicode.py, enabled auto-translation of some Asian Unicode codecs that didn’t enter the Python standard library until Python 2.4.

Version 3.1

Bug Fixes

  • Fixed minor problems with the Connection.database_info method.

Version 3.1_pre9

Version 3.1_pre9 is being released instead of 3.1 final primarily to test Python 2.4 compatibility. Since the first beta of Python 2.4 has now been released, it is expected that these binaries will continue to work throughout 2.4’s lifespan (including maintenance releases - 2.4.x).

New Features

  • Python 2.4 support (that is, a few build script changes and the availability of official Windows binaries for Python 2.4).

Bug Fixes

Version 3.1_pre8

Version 3.1_pre8 is the recommended stable version of kinterbasdb.

New Features

  • kinterbasdb._RowMapping has a richer dict-like interface (now implements __len__, __getitem__, get, __contains__, keys, values, items, __iter__, iterkeys, itervalues, iteritems).

Bug Fixes

Backward-incompatibilities

  • The kinterbasdb.services.Connection.getEnvironmentMessage method has been renamed to getMessageFileDir.
  • The kinterbasdb.services.Connection.getLog method should not have accepted a database parameter; it no longer does.

DOCUMENTATION CHANGES

  • Documented about 66% of the Services API (kinterbasdb.services module) in the KInterbasDB Usage Guide.

KNOWN ISSUES

  • The third-party fixedpoint.py module contains an incompatibility with Python 2.1 that is exposed by a bugfix applied to the kinterbasdb.typeconv_fixed_fixedpoint module in 3.1_pre8.

    No attempt will be made to fix this problem (which is a fixedpoint bug, not a kinterbasdb bug); users should either upgrade to a newer version of Python or refrain from using fixedpoint.

Version 3.1_pre7

Version 3.1_pre7 should be considered a release candidate. It is thought to be ready for production use.

New Features

  • Introduced dynamic type translation slot TEXT_UNICODE, which applies to all CHAR/VARCHAR fields except those with character sets NONE, OCTETS, or ASCII. Used in combination with the official translators in the kinterbasdb.typeconv_text_unicode module, TEXT_UNICODE enables automatic encoding/decoding of Unicode values.

    This translator is not active by default except when kinterbasdb is initialized with kinterbasdb.init(type_conv=100); the backward compatibility implications are discussed in detail in the Backward-incompatibilities section below.

    Refs: docs/usage.html#faq_fep_unicode

  • Added read-only .charset attribute to Connection.

  • On Windows, kinterbasdb now conforms to the client library loading scheme introduced in FB 1.5 RC7, so fbclient.dll need not be explicitly placed in a directory on the PATH if the registry settings are present.

Bug Fixes

Backward-incompatibilities

  • Programs that use BOTH of the following:

    • the TEXT dynamic type translation slot
    • unicode database fields

    will need to be updated to take the new TEXT_UNICODE slot into account. Since the TEXT slot is not particularly useful, this incompatibility is expected to affect very few existing programs.

    Refs: docs/usage.html#faq_fep_unicode

  • Convenience code 100 for the kinterbasdb.init function now activates the new TEXT_UNICODE translation slot, so unicode values are automatically encoded and decoded.

    Convenience code 1 remains the default, however, and it does not activate the TEXT_UNICODE slot. Programs that do BOTH of the following:

    • invoke kinterbasdb.init(type_conv=100)
    • use unicode database fields

    will need to be updated to take the new TEXT_UNICODE slot into account.

    Refs: docs/usage.html#adv_param_conv_dynamic_type_translation_tbl_convenience_codes

Version 3.1_pre6

Version 3.1_pre6 should be considered a release candidate. It is thought to be stable.

New Features

  • Added support for manual control over the phases of two-phase commit. The client programmer now has the option of triggering the first phase manually via Connection.prepare() or ConnectionGroup.prepare().

    This is useful when integrating with third-party transaction managers.

  • KInterbasDB can now be compiled “out of the box” with MinGW when building against Firebird 1.5 (but not Firebird 1.0 or Interbase).

    See docs/installation-source.html for instructions.

Bug Fixes

  • Connection.drop_database() now rolls back the connection’s active transaction (if any) before dropping the database.

    Previously, the database could be dropped with the transaction still active; when the connection was subsequently garbage collected, a rollback request was issued for the transaction (in a nonexistent database), resulting in memory corruption.

  • String values returned by input dynamic type translators were sometimes prematurely garbage collected before the database engine had read their contents.

  • SQL fields with dynamic definitions (such as expressions in a SELECT list) that involved fixed point data types (NUMERIC or DECIMAL) didn’t get passed through the FIXED dynamic type translator because the database engine does not flag dynamically defined fields properly.

    Though this is a bug in the database engine rather than KInterbasDB, a workaround was added to KInterbasDB.

    Thanks to Bert Hughes for reporting this bug.

  • The installation action of the setup script (‘setup.py install’) did not place the supporting files (documentation) in the proper directory on Linux.

    Thanks to Treeve Jelbert for reporting this bug.

Version 3.1_pre5

Version 3.1_pre5 should be considered a release candidate. It is thought to be stable.

New Features

  • Deferred loading of dynamic type translators:

    KInterbasDB’s choice of initial dynamic type translators for date/time and fixed point types is now deferred as late as possible, and the programmer has the option of controlling the choice via the type_conv parameter of the new kinterbasdb.init function.

    This feature is documented in the Usage Guide at: usage.html#adv_param_conv_dynamic_type_translation_deferred_loading

  • KInterbasDB’s setup script is now capable of compiling the source distribution “out of the box” with MinGW on Windows, but only with Firebird 1.5 or later (Borland C++ can be used with Firebird 1.0).

    This feature is documented in the installation guide for the source distribution at:

    installation-source.html#compiler_specific_compilation_notes

Bug Fixes

  • During blob insertion, not enough memory was allocated to hold the blob ID returned by the database engine, resulting in an overflow.
  • Implicit conversion of DATE/TIME/TIMESTAMP input parameters from strings to the appropriate internal types was accidentally disallowed in 3.1_pre4. This feature has been enabled again.
  • The Services API method kinterbasdb.services.Connection.restore was incapable of restoring a backup into a multi-file database because it sent the wrong cluster identifier for destination file page counts.

Backward-incompatibilities

  • Because of the new “Deferred loading of dynamic type translators” feature, the DB API type comparison singleton kinterbasdb.DATETIME will not compare equal to any type until the kinterbasdb.init function has been called (whether explicitly or implicitly).

    This issue–which is expected to affect little or no existing code–is documented in the Usage Guide at:

    usage.html#adv_param_conv_dynamic_type_translation_deferred_loading_backcompat

  • The dynamic type translation module typeconv_preferred has been renamed to typeconv_23plus.

Version 3.1_pre4

Version 3.1_pre4 should be considered a late beta release. It is thought to be stable, and there are no plans to add new features before 3.1 final (only to fix bugs and finish updating the documentation).

Note that the KInterbasDB Usage Guide has been considerably updated, though it is not quite complete. When complete, it will document all of the numerous new features in kinterbasdb 3.1; it’s a “must read” even now.

The Usage Guide is distributed with KInterbasDB (kinterbasdb-installation-dir/docs/usage.html), and is available online at: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/checkout/kinterbasdb/Kinterbasdb-3.0/docs/usage.html

New Features

  • DATABASE EVENT HANDLING has been reinstated, ported to POSIX, and timeout support has been added.

    This feature is thoroughly documented in the updated Usage Guide.

    Refs: http://sourceforge.net/tracker/index.php?func=detail&aid=637796&group_id=9913&atid=109913

  • DISTRIBUTED TRANSACTIONS are now supported via the kinterbasdb.ConnectionGroup class.

    Although the Usage Guide does not yet fully document this feature, it does contain an example program and a few hints: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/checkout/kinterbasdb/Kinterbasdb-3.0/docs/usage.html#adv_trans_control_distributed

  • DYNAMIC TYPE TRANSLATION

    KInterbasDB 3.1_pre4 implements two-way “dynamic type translation”. This feature allows the client programmer to change the type conversion methods for specific SQL data types and achieve complete “type transparency”. For example, KInterbasDB 3.1_pre4 includes reference implementations of converters for both input and output of ‘mx.DateTime’ and Python 2.3 stdlib ‘datetime’ for TIME/DATE/TIMESTAMP fields.

    One consequence of two-way dynamic type translation support is that KInterbasDB 3.1_pre4 can be used with Python 2.3’s datetime module occupying the former role mx.DateTime. For backward compatibility, mx.DateTime is still the default, and it will remain so.

    This feature is documented in the updated Usage Guide.

  • Cursor.rowcount support has been added (insofar as the database engine supports it).

    This feature is documented in the updated Usage Guide.

    Refs: http://sourceforge.net/forum/forum.php?thread_id=866629&forum_id=30917

  • SAVEPOINTs (a Firebird 1.5 feature) are exposed at the Python level via the Connection.savepoint(savepoint=’name’) method and the optional $savepoint argument to the Cursor.rollback method.

    This feature is documented in the updated Usage Guide.

  • New attributes suggested by the “Optional DB API Extensions” section of PEP 249:

    • Access to a cursor’s connection via the Cursor.connection attribute.
    • Access to kinterbasdb’s exception classes via connection attributes.

    Refs: http://www.python.org/peps/pep-0249.html

  • A cursor can now be reused after it has caused an exception.

Bug Fixes

  • Passing the wrong number of parameters for a parameterized SQL statement sometimes caused a crash instead of an exception with kinterbasdb 3.1_pre3. This would not have affected client programs that were written correctly, but it was still a bug.

  • The kinterbasdb.create_database function leaked memory if it encountered an error.

  • Additional Windows binaries are being released to avoid dynamic linking problems with Interbase 5.5 and Firebird 1.5-embedded.

    Refs: http://sourceforge.net/tracker/index.php?func=detail&aid=707644&group_id=9913&atid=109913 http://sourceforge.net/forum/forum.php?thread_id=855348&forum_id=30917

  • kinterbasdb now builds with less hassle on FreeBSD.

    Refs: http://sourceforge.net/tracker/index.php?func=detail&aid=720021&group_id=9913&atid=109913

  • Whenever a transactional context is needed, a transaction is now started implicitly if the Python programmer has not started one explicitly with Connection.begin. This implicit behavior is implicitly required by the Python DB API specification.

    Refs: http://mail.python.org/pipermail/db-sig/2003-February/003158.html

  • The mapping objects returned from the Cursor.fetch*map() method now accept “double-quoted” field names (lookup keys). If the field name is double-quoted, its original case will be preserved–instead of being normalized to upper case–when the result set is searched for a field with that name.

    For example, if a table were defined this way:

    create table tbl ("sTRanGelyCasEDfieldnAme" integer)

    and the statement:

    cur.execute("select * from tbl")

    were executed against it, the mapping objects returned by:

    cur.fetchonemap()

    would have rejected the lookup key ‘sTRanGelyCasEDfieldnAme’, converting it instead to ‘STRANGELYCASEDFIELDNAME’ and then failing to find the upper-cased field name.

    The solution available in 3.1_pre4 is to perform the lookup this way:

    cur.execute("select * from tbl")
mapping = cur.fetchonemap()
mapping['"sTRanGelyCasEDfieldnAme"']
         ^-----double-quoted-----^

    which will force the preservation of the field name’s case.

    An easy way to avoid problems such as this is to refrain from using quoted identifiers; in that case, the database engine will treat identifiers in a case-insensitive manner.

    Refs: http://sourceforge.net/tracker/index.php?func=detail&aid=720130&group_id=9913&atid=109913

INTERNAL CHANGES

  • kinterbasdb now implements its standard date/time and fixed point handling via the new, general-purpose dynamic type translation feature.

    This eliminates the C-compile-time dependency on mx.DateTime. Although mx.DateTime (for date/time types) and Connection.precision_mode (for precise fixed point types) still function as before, dynamic type translation allows other types to be transparently substituted (such as those in Python 2.3’s standard library datetime module for date/time types, or those in the fixedpoint module for precise fixed point types).

    For more information, see the Usage Guide.

Backward-incompatibilities

There are no outright incompatibilities, but there is one deprecation:

  • Although Connection.precision_mode continues to function as in earlier versions, it is deprecated in favor of dynamic type translation. The functionality that Connection.precision_mode delivers (precise I/O of fixed point values) is now implemented at the Python level via dynamic type translation, rather than at the C level.

    If you explicitly use both Connection.precision_mode and dynamic type translation, beware that changing the value of Connection.precision_mode will cause changes to the registered dynamic type converters under the hood.

    For more information, see the INTERNAL CHANGES section above, and the Usage Guide.

Version 3.1_pre3

Version 3.1_pre3 should be considered a beta release.

New Features

  • database array support

    Database arrays are mapped from Python sequences (except strings) on input; to Python lists on output. On output, the lists will be nested if the database array has multiple dimensions.

    I’m not impressed by the Interbase/Firebird implementation of database arrays. The database engine claims to support up to 16 dimensions, but actually malfunctions catastrophically* above 10.

    The arrays are of fixed size, with a predeclared number of dimensions and number of elements per dimension. Individual array elements cannot be set to NULL/None**, so the mapping between Python lists (which have dynamic length and are therefore not normally null-padded) and non-trivial database arrays is clumsy.

    Arrays cannot be passed as parameters to, or returned from, stored procedures.

    Finally, many interface libraries, GUIs, and even the isql command line utility do not support arrays. Refs:

    ** Interbase 6 API Guide page 153.

  • retaining commit/retaining rollback

    The commit() and rollback() methods of kinterbasdb.Connection now accept an optional boolean parameter ‘retaining’ (default False). If retaining is True, the infrastructural support for the transaction active at the time of the method call will be “retained” (efficiently and transparently recycled) after the database server has committed or rolled back the conceptual transaction.

    In code that commits or rolls back frequently, ‘retaining’ the transaction yields considerably better performance. ‘retaining’ will become the default at some point in the future if the switch can be made without serious backward compatibility issues.

    Refs: http://sourceforge.net/forum/forum.php?thread_id=799246&forum_id=30917 Interbase 6 API Guide page 74.

  • unicode strings can now be executed via:

    • kinterbasdb.Cursor.execute[many]()
    • kinterbasdb.Cursor.callproc()
    • kinterbasdb.Connection.execute_immediate()

    However, the encoding of the incoming unicode string is rather simplistic–via PyUnicode_AsASCIIString.

Bug Fixes

  • Addressed buffer overflow potential in:

    • kinterbasdb.create_database()
    • kinterbasdb.connect()
    • kinterbasdb.Connection.begin()
    • kinterbasdb.Connection.execute_immediate()
    • kinterbasdb.Cursor.execute() (and thence, executemany() and callproc())

  • Fixed reference count leaks in:

    • exception handling (_exception_functions.c)
    • field precision determination (_kiconversion_field_precision.c)

  • Fixed kinterbasdb.Connection.close() bug: The physical connection to the database server was not actually closed until the kinterbasdb.Connection instance was garbage collected.

  • Fixed a bug in the kinterbasdb.services.Connection.userExists() method. Usernames are now normalized to upper case.

  • Database version compatibility:

    • kinterbasdb compiles properly against Firebird 1.5.

    • kinterbasdb compiles against and ought to work with (but has not been tested with) Interbase 5.5, albeit with some lost functionality, namely:

      • field precision determination (the precision entry in cursor.description)
      • Services API support
      • retaining rollback
      • various data storage options, such as precise 64-bit integer storage of NUMERIC and DECIMAL values (IB 5.5 uses doubles instead, which is not really adequate) and more diverse date/time types.

    Refs: http://sourceforge.net/tracker/index.php?func=detail&aid=627816&group_id=9913&atid=109913 IB 6 Data Definition Guide page 65.

  • Improved DB API compliance:

    • Now, there need not be an active transaction before any execute(), commit(), or rollback() call; transaction establishment is implicit in these cases.
    • Cursors no longer need to be discarded after an exception; the same cursor can be reused. Of course if the cursor was in the process of fetching a result set, the remainder of the set will not be available after the exception.

INTERNAL CHANGES

  • Numerous modest optimizations, especially with regard to memory handling. Among these is a move to take advantage of Python 2.3’s specialized, Python-oriented memory manager.
  • MAJOR code refactoring and tidying.

Backward-incompatibilities

  • Invalid argument combinations to the connect() function now raise a ProgrammingError rather than an InterfaceError. Note that this refers to invalid combinations of arguments, not necessarily to invalid values for those arguments.

  • Non-keyword-argument forms of connect() are now deprecated; passing non-keyword arguments to connect() results in a DeprecationWarning being issued via the standard Python warning framework. This is a warning, not an incompatibility in the strict sense.

    Refs: http://www.python.org/doc/current/lib/module-warnings.html

  • Official support for database event handling has been deferred until 3.2. A Win32-only prototype will still be included with the kinterbasdb 3.1 source distribution (but not compiled by default).

    Refs: docs/usage.html#database_events_unsupported

Version 3.1_pre2

New Features

  • Global Interpreter Lock management

    Previously, kinterbasdb operated in a serial manner, with the sole exception of the event handling code, whose parallelism is “under the hood”. Aside from event handling, all kinterbasdb operations, including potentially long-running Firebird API calls, were serialized by the Python GIL.

    With the advent of kinterbasdb 3.1_pre2, kinterbasdb releases the GIL where appropriate–that is, when it is about to make a potentially long- running Firebird API call, and can do so without invoking the Python API, or otherwise operating on Python structures.

    However, the Firebird client library itself is not threadsafe, so Firebird API calls must also be serialized. To that end, kinterbasdb maintains a process-wide thread lock around which all Firebird API calls are serialized.

    When kinterbasdb is about to make a potentially long-running Firebird API call, it follows these steps:

    1. Extract necessary parameter data from Python structures

    2. Release the Python GIL

    3. Acquire the kinterbasdb process-wide Firebird client thread lock

    4. Execute the Firebird API call

    5. Release the kinterbasdb process-wide Firebird client thread lock

    6. Acquire the Python GIL

    7. Modify Python structures to reflect the results of the Firebird API

      call

    The addition of GIL management should improve kinterbasdb’s maximum possible throughput for multi-threaded Python programs on multi-processor systems (one processor can run the Python interpreter while another executes a Firebird client library operation). GIL management may also yield greater “responsiveness” for multi-threaded Python programs running on single-processor systems.

    The addition of GIL management required fairly extensive internal changes, and therefore warranted a whole prerelease version virtually unto itself.

  • Cursor name support

    The read/write property Cursor.name allows the Python programmer to perform scrolling UPDATEs or DELETions via the “SELECT ... FOR UPDATE” syntax. If you don’t know what this means, refer to the database SQL syntax documentation of the FOR UPDATE clause of the SELECT statement. The Cursor.name property can be ignored entirely if you don’t need to use it.

    Here’s an example code fragment:

    con = ... # establish a kinterbasdb.Connection
curScroll = con.cursor()
curUpdate = con.cursor()

curScroll.execute('select city from customer for update')
curScroll.name = 'city_scroller'
update = 'update customer set city=? where current of ' + curScroll.name

for (city,) in curScroll:
    city = ... # make some changes to city
    curUpdate.execute( update, (city,) )

Version 3.1_pre1

Version 3.1_pre1 should be considered an early alpha release.

New Features

This list of new features represents the state of kinterbasdb 3.1_pre1, which does not include some features slated for inclusion in the final release of kinterbasdb 3.1. For a discussion of the ultimate goals of version 3.1, see: http://sourceforge.net/forum/forum.php?thread_id=696302&forum_id=30917

Also, the documentation has not yet been updated to cover these new features, nor will it be for at least another month. In the meantime, those who need to use the new features must refer to the source code.

  • Cursor Iteration Support

    When used with Python 2.2 or later, kinterbasdb’s Cursors now support

    “natural” iteration. For example:

    # Index-based field lookup (based on Cursor.fetchone):
cur = con.cursor()
cur.execute("select col1, col2 from the_table")
for row in cur:
    col1 = row[0]

# Key-based field lookup (based on Cursor.fetchonemap):
cur = con.cursor()
cur.execute("select col1, col2 from the_table")
for rowMap in cur.itermap():
    col1 = rowMap['col1']

    The iterator-based pattern supercedes the ugly fetch pattern of old (though of course the old pattern will still work):

    # Index-based field lookup (based on Cursor.fetchone):
cur = con.cursor()
cur.execute("select col1, col2 from the_table")
while 1:
    row = cur.fetchone()
    if not row:
        break

    col1 = row[0]

  • Implicit Parameter Conversion

    Implicit parameter conversion allows any SQL datatype supported by kinterbasdb to be passed to the database engine as a Python string.

    This is especially useful for parameterized statements that involve date/time datatypes, because they can now accept server-computed “magic” values such as ‘now’ and ‘current_date’ more naturally. Implicit parameter conversion is also likely to yield a speedup for programs that load external data from flat files into the database, since the incoming values do not need to be converted from their original string representation into an acceptable Python type before being forwarded to the database.

    For a more thorough discussion of this new feature, see: http://sourceforge.net/tracker/index.php?func=detail&aid=531828&group_id=9913&atid=309913

  • Services API Support (see IB 6 API Guide Chapter 12)

    The database engine provides an API (the Services API) to facilitate programmatic invocation of the maintenance tasks available through the command-line tools gbak, gfix, etc.

    I’ve wrapped nearly the entire Services API in a thick Python API of my own design. My API design is only provisional; I seek feedback as to how it could be made more elegant. The Services API support is accessible via the kinterbasdb.services module.

  • Database Event Support (see IB 6 API Guide Chapter 11)

    The database engine allows client programs to register to be informed of the occurrence of database events, which can be raised with the POST_EVENT statement in stored procedures or triggers. kinterbasdb 3.1 supports a subset of this functionality (synchronous waiting only) via the Connection.wait(eventNames) method.

    The current implementation is only a rough prototype; though usable, it is not recommended for production environments.

    The current implementation suffers from a major limitation: only one thread per process is allowed to listen for event notification. This is so because the current implementation resorts to some roundabout trickery to circumvent the lack of database API support for synchronous event notification on Windows. Because the database API only starts one asynchronous event handler thread per process, I doubt that support for multiple event-listening threads in a single process will materialize.

Bug Fixes

  • In the past, the opaque mapping object returned by the Cursor.fetch*map methods returned None when asked for a field not in its select list, rather than raising a KeyError. It now raises a KeyError in such a case. For example:

    cur = con.cursor()
cur.execute("select col1, col2 from the_table")
for rowMap in cur.itermap():
    x = rowMap['col3'] # Used to return None.  Now raises KeyError,
                       # because col3 was not SELECTed.

Backward-incompatibilities

  • Although kinterbasdb 3.1 is significantly different internally, there is only one known API incompatibility with version 3.0.2. It would only arise in code that relies on the erroneous behavior of the mapping-fetch bug mentioned above.
  • Python versions prior to 2.1 are no longer officially supported. Although kinterbasdb might still compile against Python 2.0 and earlier, I will not go out of my way to ensure that it does.

Version 3.0.2

Bug Fixes

Version 3.0.1

Bug Fixes

  • Adjusted input handling of NULL values. The new scheme raises an exception immediately when it detects that a Python None value has arrived for storage in a database field or parameter that disallows NULL values.

    The old scheme simply accepted the Python None value and then tried to execute the query, relying on the database API to detect the error. With certain data types, the database API would silently insert a bogus value rather than detecting the error.

  • Scrutinized the datetime input/output facilities, found some incompatibilities with the DB API, and corrected them. These changes are backward-incompatible, but are warranted because the previous behavior was in defiance of the specification. See further notes about the nature of these changes in the backward-incompatibilities section.

  • Fixed a memory leak that affected the storage of Python string input parameters in BLOB fields.

  • Fixed a rollback-related bug that arose if a connection to a database was established, but a transaction was never started on that connection. In such a case, a spurious exception was raised when the connection was garbage collected.

    Normal code would not have invoked this bug, but it was still a bug.

Backward-incompatibilities

  • Datetime input/output has changed to better comply with the DB API (see datetime bugfix discussion above).

    Code that uses the mx.DateTime module directly (rather than the kinterbasdb DB API datetime constructors) should not be affected.

    For details, see the comments in the code block in __init__.py tagged with “DSR:2002.07.19”.

Version 3.0.1_pre3

Bug Fixes

  • Bug #572326 (which was not present in kinterbasdb 3.0 and never affected Python 2.2+) caused several numeric types to not be transferred from Python to the database engine when they were passed as query parameters.

    This was a serious bug; it caused even such fundamental operations as: cursor.execute(“insert into the_table values (?)”, (1,)) to not work correctly.

Version 3.0.1_pre2

Bug Fixes

  • CHAR output now doesn’t have such problems with multibyte character sets and values shorter than the maximum declared length of the field.

    CHARs are no longer returned with their trailing blanks intact. The trailing blanks have been abandoned because they were in fact NULL characters, not spaces. kinterbasdb would fill in the spaces manually, except for the problems that approach causes with multibyte character sets.

  • Fixed a potential buffer overflow, but the fix only applies when compiled against Python 2.2 or later.

Backward-incompatibilities

  • See coverage of CHAR output changes in the ‘Bug Fixes’ section. In a nutshell: CHAR output values no longer have trailing NULL bytes.

Version 3.0.1_pre1

New Features

  • It is now possible to connect to a database under a specific role by using the ‘role’ keyword argument of the kinterbasdb.connect function.
  • The following methods now accept any sequence except a string for their ‘parameter’ argument, rather than demanding a tuple: Cursor.execute, Cursor.executemany and Cursor.callproc.

Bug Fixes

  • kinterbasdb supports IB 5.x again.

    Various identifiers specific to IB 6.x/Firebird had crept into unguarded areas of __init__.py and _kinterbasdb.c, but this has been changed so that kinterbasdb compiles gracefully with IB 5.x. See: http://sourceforge.net/tracker/index.php?func=detail&aid=553184&group_id=9913&atid=209913

  • The distutils setup script no longer raises a ValueError on Windows 2000 or XP.

  • The precision slot in Cursor.description was always zero. It now contains the correct value if that value can reasonably be determined.

    Note that the database engine records the precision of some fields as zero (e.g., FLOAT), and the slot will also be zero in cases where the database engine does not expose the precision of the field (e.g., dynamic fields such as “SELECT 33.5 FROM RDB$DATABASE”).

    Since the database API does not provide the field’s precision figure in the XSQLVAR structure, it is necessary to query the system tables. In order to minimize the performance hit, precision figures are cached per Connection; the determination of a given field’s precision figure in the context of a given Connection will require only dictionary lookups after it is determined the first time with a system table query.

    An unfortunate side effect of this caching is that if a field’s precision is altered after the figure has been cached in by a Connection, cursors based on that Connection will still show the old precision figure. In practice, this situation will almost never arise. See: http://sourceforge.net/tracker/index.php?func=detail&aid=549982&group_id=9913&atid=109913

  • On Linux, attempting to fetch immediately after having executed a non-query statement resulted in a segfault. An exception is now raised instead. The problem did not afflict Windows, which always raised the exception. See: http://sourceforge.net/tracker/index.php?func=detail&aid=551098&group_id=9913&atid=109913

    • The message carried by this exception grew without bound in on both Windows and Linux. It no longer does.

  • Under some circumstances, the fetched values of CHAR fields were incorrect. CHAR values now appear as expected (they are left-padded with spaces and always of length equal to their field’s designated maximum length).

  • Cursor.fetchmany raised an error if there were no remaining values to fetch. It now returns an empty sequence instead, as required by the DB API Specification.

  • Field domains are checked more strictly. It is now impossible to (for example) issue a statement that attempts to insert a 12-character string into a 10-character CHAR field without encountering an exception.

    This checking is not perfect, since it validates against the field’s internal storage type rather than the field’s declared type. For example, a NUMERIC(1,1), which is stored internally as a short, will erroneously accept the value 12.5 because 125 fits in a short.

  • When operating in imprecise mode (connection.precision_mode == 0), kinterbasdb 3.0 sometimes interpreted integer values as though it were operating in precise mode.

Version 3.0 versus 2.0-0.3.1

New Features

The new features are thoroughly documented in the KInterbasDB Usage Guide (usage.html); they need not be reiterated here. However, backward-incompatible changes have been documented in this changelog (see the Backward-incompatibilities section).

Bug Fixes

Many bugs have been fixed, including (but not limited to) the following, which were registered with the KInterbasDB bug tracker at SourceForge ( http://sourceforge.net/tracker/index.php?group_id=9913&atid=109913 ):

  • 433090 cannot connect to firebird server
  • 438130 cursor.callproc not adding param code
  • 468304 fetchmany return all record
  • 498086 ignores column aliases in select
  • 498403 fetching after a callproc hangs program
  • 498414 execute procedure message length error
  • 505950 inconsistent fetch* return types
  • 515974 Wrong decoding of FB isc_version
  • 517093 broken fixed-point handling in 3.0
  • 517840 C function normalize_double inf. loop
  • 517842 fetch bug - program hangs
  • 520793 poor DB API compliance ^ a BIG fix that entailed many changes
  • 522230 error with blobs larger than (2^16) - 1
  • 522774 inconsistent fixed-point conv in 3.0-rc2
  • 523348 memory leak in Blob2PyObject
  • immediate execution facilities unreliable in 2.x

Backward-incompatibilities

As a result of the changes required for some of the bugfixes (especially #520793 - “poor DB API compliance”) and general reengineering, several areas of backward-incompatibility have arisen:

  • fetch* return types

    The standard fetch(one|many|all) methods now return just a sequence, not a combined sequence/mapping. If you want a mapping, use one of the fetch(one|many|all)map methods.

    Note the “‘absolutely no guarantees’ except...” caveats in the KInterbasDB Usage Guide regarding the return types of the Cursor.fetch* methods and the contents of the Cursor.description attribute.

    This is a significant backward-incompatibility, and was not undertaken without serious consideration (for evidence see http://sourceforge.net/forum/forum.php?thread_id=622782&forum_id=30919 ).

  • Fixed point number handling

    Fixed point number handling has been remodelled. By default, fixed point numbers (NUMERIC/DECIMAL field values) are now represented (with a potential loss of precision) as Python floats.

    A Connection.precision_mode attribute has been added so that precise representation of fixed point values as scaled Python integers (as in KInterbasDB 2.x) can be used at will.

    For more information, see the KInterbasDB Usage Guide.

  • Connection.dialect

    In KInterbasDB 2.x, the default connection dialect was 1 (the backward-compatibility dialect for use with Interbase 5.5 and earlier).

    KInterbasDB 3.0 is being released into quite a different climate. Interbase 6.0 was released nearly two years ago, and Firebird 1.0 has recently been released. Because it is expected that KInterbasDB 3.0 will be used most frequently with Interbase 6.0+ and Firebird, the default connection dialect is 3.

    Using KInterbasDB 3.0 with Interbase 5.5 and earlier is still possible, though untested by the developers of KInterbasDB 3.0. See the Connection.dialect documentation in the KInterbasDB Usage Guide for an explanation of how to initialize a connection with a dialect other than 3.

  • Connection.server_version

    The Connection.server_version attribute is now a string rather than an integer. An integer simply was not expressive enough to represent the numerous Interbase variants that exist today (including Firebird, which does not fit neatly into the Interbase version progression).

    For more information, see the KInterbasDB Usage Guide.

  • kinterbasdb.execute_immediate

    The kinterbasdb.execute_immediate function has been removed. A similar function named kinterbasdb.create_database has been added. The primary differences between kinterbasdb.execute_immediate and kinterbasdb.create_database are:

    • kinterbasdb.create_database is not as general
    • kinterbasdb.create_database actually works

    The execute_immediate method of the Connection class has been retained.

    For more information, see the KInterbasDB Usage Guide.

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