Sqlalchemy

:released: Sat Jun 02 2007

.. change::
:tags: engines
:tickets:

added detach() to Connection, allows underlying DBAPI connection
to be detached from its pool, closing on dereference/close()
instead of being reused by the pool.

.. change::
:tags: engines
:tickets:

added invalidate() to Connection, immediately invalidates the
Connection and its underlying DBAPI connection.

.. change::
:tags: sql
:tickets:

_Label class overrides compare_self to return its ultimate
object. meaning, if you say someexpr.label('foo') == 5, it
produces the correct "someexpr == 5".

.. change::
:tags: sql
:tickets:

_Label propagates "_hide_froms()" so that scalar selects
behave more properly with regards to FROM clause 574

.. change::
:tags: sql
:tickets:

fix to long name generation when using oid_column as an order by
(oids used heavily in mapper queries)

.. change::
:tags: sql
:tickets:

significant speed improvement to ResultProxy, pre-caches
TypeEngine dialect implementations and saves on function calls
per column

.. change::
:tags: sql
:tickets:

parenthesis are applied to clauses via a new _Grouping
construct. uses operator precedence to more intelligently apply
parenthesis to clauses, provides cleaner nesting of clauses
(doesn't mutate clauses placed in other clauses, i.e. no 'parens'
flag)

.. change::
:tags: sql
:tickets:

added 'modifier' keyword, works like func.<foo> except does not
add parenthesis. e.g. select([modifier.DISTINCT(...)]) etc.

.. change::
:tags: sql
:tickets: 578

removed "no group by's in a select that's part of a UNION"
restriction

.. change::
:tags: orm
:tickets:

added reset_joinpoint() method to Query, moves the "join point"
back to the starting mapper. 0.4 will change the behavior of
join() to reset the "join point" in all cases so this is an
interim method. for forwards compatibility, ensure joins across
multiple relations are specified using a single join(), i.e.
join(['a', 'b', 'c']).

.. change::
:tags: orm
:tickets:

fixed bug in query.instances() that wouldn't handle more than
on additional mapper or one additional column.

.. change::
:tags: orm
:tickets:

"delete-orphan" no longer implies "delete". ongoing effort to
separate the behavior of these two operations.

.. change::
:tags: orm
:tickets:

many-to-many relationships properly set the type of bind params
for delete operations on the association table

.. change::
:tags: orm
:tickets:

many-to-many relationships check that the number of rows deleted
from the association table by a delete operation matches the
expected results

.. change::
:tags: orm
:tickets:

session.get() and session.load() propagate \**kwargs through to
query

.. change::
:tags: orm
:tickets: 577

fix to polymorphic query which allows the original
polymorphic_union to be embedded into a correlated subquery

.. change::
:tags: orm
:tickets:

fix to select_by(<propname>=<object instance>) -style joins in
conjunction with many-to-many relationships, bug introduced in
r2556

.. change::
:tags: orm
:tickets:

the "primary_key" argument to mapper() is propagated to the
"polymorphic" mapper. primary key columns in this list get
normalized to that of the mapper's local table.

.. change::
:tags: orm
:tickets:

restored logging of "lazy loading clause" under
sa.orm.strategies logger, got removed in 0.3.7

.. change::
:tags: orm
:tickets:

improved support for eagerloading of properties off of mappers
that are mapped to select() statements; i.e. eagerloader is
better at locating the correct selectable with which to attach
its LEFT OUTER JOIN.

.. change::
:tags: mysql
:tickets:

Nearly all MySQL column types are now supported for declaration
and reflection. Added NCHAR, NVARCHAR, VARBINARY, TINYBLOB,
LONGBLOB, YEAR

.. change::
:tags: mysql
:tickets:

The sqltypes.Binary passthrough now always builds a BLOB,
avoiding problems with very old database versions

.. change::
:tags: mysql
:tickets:

support for column-level CHARACTER SET and COLLATE declarations,
as well as ASCII, UNICODE, NATIONAL and BINARY shorthand.

.. change::
:tags: firebird
:tickets:

set max identifier length to 31

.. change::
:tags: firebird
:tickets:

supports_sane_rowcount() set to False due to ticket 370.
versioned_id_col feature won't work in FB.

.. change::
:tags: firebird
:tickets:

some execution fixes

.. change::
:tags: firebird
:tickets:

new association proxy implementation, implementing complete
proxies to list, dict and set-based relation collections

.. change::
:tags: firebird
:tickets:

added orderinglist, a custom list class that synchronizes an
object attribute with that object's position in the list

.. change::
:tags: firebird
:tickets:

small fix to SelectResultsExt to not bypass itself during
select().

.. change::
:tags: firebird
:tickets:

added filter(), filter_by() to assignmapper

.. changelog::

:released: Sun Apr 29 2007

.. change::
:tags: engines
:tickets:

warnings module used for issuing warnings (instead of logging)

.. change::
:tags: engines
:tickets: 480

cleanup of DBAPI import strategies across all engines

.. change::
:tags: engines
:tickets:

refactoring of engine internals which reduces complexity,
number of codepaths; places more state inside of ExecutionContext
to allow more dialect control of cursor handling, result sets.
ResultProxy totally refactored and also has two versions of
"buffered" result sets used for different purposes.

.. change::
:tags: engines
:tickets: 514

server side cursor support fully functional in postgres.

.. change::
:tags: engines
:tickets:

improved framework for auto-invalidation of connections that have
lost their underlying database, via dialect-specific detection
of exceptions corresponding to that database's disconnect
related error messages. Additionally, when a "connection no
longer open" condition is detected, the entire connection pool
is discarded and replaced with a new instance. 516

.. change::
:tags: engines
:tickets: 521

the dialects within sqlalchemy.databases become a setuptools
entry points. loading the built-in database dialects works the
same as always, but if none found will fall back to trying
pkg_resources to load an external module

.. change::
:tags: engines
:tickets:

Engine contains a "url" attribute referencing the url.URL object
used by create_engine().

.. change::
:tags: sql
:tickets:

keys() of result set columns are not lowercased, come back
exactly as they're expressed in cursor.description. note this
causes colnames to be all caps in oracle.

.. change::
:tags: sql
:tickets:

preliminary support for unicode table names, column names and
SQL statements added, for databases which can support them.
Works with sqlite and postgres so far. MySQL *mostly* works
except the has_table() function does not work. Reflection
works too.

.. change::
:tags: sql
:tickets: 522

the Unicode type is now a direct subclass of String, which now
contains all the "convert_unicode" logic. This helps the variety
of unicode situations that occur in db's such as MS-SQL to be
better handled and allows subclassing of the Unicode datatype.

.. change::
:tags: sql
:tickets:

ClauseElements can be used in in_() clauses now, such as bind
parameters, etc. 476

.. change::
:tags: sql
:tickets:

reverse operators implemented for `CompareMixin` elements,
allows expressions like "5 + somecolumn" etc. 474

.. change::
:tags: sql
:tickets:

the "where" criterion of an update() and delete() now correlates
embedded select() statements against the table being updated or
deleted. this works the same as nested select() statement
correlation, and can be disabled via the correlate=False flag on
the embedded select().

.. change::
:tags: sql
:tickets: 512

column labels are now generated in the compilation phase, which
means their lengths are dialect-dependent. So on oracle a label
that gets truncated to 30 chars will go out to 63 characters
on postgres. Also, the true labelname is always attached as the
accessor on the parent Selectable so there's no need to be aware
of the "truncated" label names.

.. change::
:tags: sql
:tickets:

column label and bind param "truncation" also generate
deterministic names now, based on their ordering within the
full statement being compiled. this means the same statement
will produce the same string across application restarts and
allowing DB query plan caching to work better.

.. change::
:tags: sql
:tickets: 513

the "mini" column labels generated when using subqueries, which
are to work around glitchy SQLite behavior that doesn't understand
"foo.id" as equivalent to "id", are now only generated in the case
that those named columns are selected from (part of)

.. change::
:tags: sql
:tickets:

the label() method on ColumnElement will properly propagate the
TypeEngine of the base element out to the label, including a label()
created from a scalar=True select() statement.

.. change::
:tags: sql
:tickets: 513

MS-SQL better detects when a query is a subquery and knows not to
generate ORDER BY phrases for those

.. change::
:tags: sql
:tickets: 505

fix for fetchmany() "size" argument being positional in most
dbapis

.. change::
:tags: sql
:tickets:

sending None as an argument to func.<something> will produce
an argument of NULL

.. change::
:tags: sql
:tickets:

query strings in unicode URLs get keys encoded to ascii
for \**kwargs compat

.. change::
:tags: sql
:tickets: 523

slight tweak to raw execute() change to also support tuples
for positional parameters, not just lists

.. change::
:tags: sql
:tickets:

fix to case() construct to propagate the type of the first
WHEN condition as the return type of the case statement

.. change::
:tags: orm
:tickets:

fixed critical issue when, after options(eagerload()) is used,
the mapper would then always apply query "wrapping" behavior
for all subsequent LIMIT/OFFSET/DISTINCT queries, even if no
eager loading was applied on those subsequent queries.

.. change::
:tags: orm
:tickets: 541

added query.with_parent(someinstance) method. searches for
target instance using lazy join criterion from parent instance.
takes optional string "property" to isolate the desired relation.
also adds static Query.query_from_parent(instance, property)
version.

.. change::
:tags: orm
:tickets: 554

improved query.XXX_by(someprop=someinstance) querying to use
similar methodology to with_parent, i.e. using the "lazy" clause
which prevents adding the remote instance's table to the SQL,
thereby making more complex conditions possible

.. change::
:tags: orm
:tickets:

added generative versions of aggregates, i.e. sum(), avg(), etc.
to query. used via query.apply_max(), apply_sum(), etc.
552

.. change::
:tags: orm
:tickets:

fix to using distinct() or distinct=True in combination with
join() and similar

.. change::
:tags: orm
:tickets:

corresponding to label/bindparam name generation, eager loaders
generate deterministic names for the aliases they create using
md5 hashes.

.. change::
:tags: orm
:tickets:

improved/fixed custom collection classes when giving it "set"/
"sets.Set" classes or subclasses (was still looking for append()
methods on them during lazy loads)

.. change::
:tags: orm
:tickets:

restored old "column_property()" ORM function (used to be called
"column()") to force any column expression to be added as a property
on a mapper, particularly those that aren't present in the mapped
selectable. this allows "scalar expressions" of any kind to be
added as relations (though they have issues with eager loads).

.. change::
:tags: orm
:tickets: 533

fix to many-to-many relationships targeting polymorphic mappers

.. change::
:tags: orm
:tickets: 543

making progress with session.merge() as well as combining its
usage with entity_name

.. change::
:tags: orm
:tickets:

the usual adjustments to relationships between inheriting mappers,
in this case establishing relation()s to subclass mappers where
the join conditions come from the superclass' table

.. change::
:tags: informix
:tickets:

informix support added ! courtesy James Zhang, who put a ton
of effort in.

.. change::
:tags: sqlite
:tickets:

removed silly behavior where sqlite would reflect UNIQUE indexes
as part of the primary key (?!)

.. change::
:tags: oracle
:tickets:

small fix to allow successive compiles of the same SELECT object
which features LIMIT/OFFSET. oracle dialect needs to modify
the object to have ROW_NUMBER OVER and wasn't performing
the full series of steps on successive compiles.

.. change::
:tags: mysql
:tickets:

support for SSL arguments given as inline within URL query string,
prefixed with "ssl\_", courtesy terjerosgmail.com.

.. change::
:tags: <schemaname>, mysql
:tickets:

mysql uses "DESCRIBE.<tablename>", catching exceptions
if table doesn't exist, in order to determine if a table exists.
this supports unicode table names as well as schema names. tested
with MySQL5 but should work with 4.1 series as well. (557)

.. change::
:tags: extensions
:tickets:

big fix to AssociationProxy so that multiple AssociationProxy
objects can be associated with a single association collection.

.. change::
:tags: extensions
:tickets:

assign_mapper names methods according to their keys (i.e. __name__)
551

.. change::
:tags: mssql
:tickets:

pyodbc is now the preferred DB-API for MSSQL, and if no module is
specifically requested, will be loaded first on a module probe.

.. change::
:tags: mssql
:tickets:

The SCOPE_IDENTITY is now used instead of IDENTITY. This
behavior may be overridden with the engine_connect
"use_scope_identity" keyword parameter, which may also be specified
in the dburi.

.. changelog::

:released: Fri Mar 23 2007

.. change::
:tags: sql
:tickets:

bindparam() names are now repeatable! specify two
distinct bindparam()s with the same name in a single statement,
and the key will be shared. proper positional/named args translate
at compile time. for the old behavior of "aliasing" bind parameters
with conflicting names, specify "unique=True" - this option is
still used internally for all the auto-generated (value-based)
bind parameters.

.. change::
:tags: sql
:tickets:

slightly better support for bind params as column clauses, either
via bindparam() or via literal(), i.e. select([literal('foo')])

.. change::
:tags: sql
:tickets:

MetaData can bind to an engine either via "url" or "engine" kwargs
to constructor, or by using connect() method. BoundMetaData is
identical to MetaData except engine_or_url param is required.
DynamicMetaData is the same and provides thread-local connections be
default.

.. change::
:tags: sql
:tickets:

exists() becomes usable as a standalone selectable, not just in a
WHERE clause, i.e. exists([columns], criterion).select()

.. change::
:tags: sql
:tickets:

correlated subqueries work inside of ORDER BY, GROUP BY

.. change::
:tags: sql
:tickets:

fixed function execution with explicit connections, i.e.
conn.execute(func.dosomething())

.. change::
:tags: sql
:tickets:

use_labels flag on select() won't auto-create labels for literal text
column elements, since we can make no assumptions about the text. to
create labels for literal columns, you can say "somecol AS
somelabel", or use literal_column("somecol").label("somelabel")

.. change::
:tags: sql
:tickets:

quoting won't occur for literal columns when they are "proxied" into
the column collection for their selectable (is_literal flag is
propagated). literal columns are specified via
literal_column("somestring").

.. change::
:tags: sql
:tickets:

added "fold_equivalents" boolean argument to Join.select(), which
removes 'duplicate' columns from the resulting column clause that
are known to be equivalent based on the join condition. this is of
great usage when constructing subqueries of joins which Postgres
complains about if duplicate column names are present.

.. change::
:tags: sql
:tickets: 503

fixed use_alter flag on ForeignKeyConstraint

.. change::
:tags: sql
:tickets: 506

fixed usage of 2.4-only "reversed" in topological.py

.. change::
:tags: sql
:tickets: 501

for hackers, refactored the "visitor" system of ClauseElement and
SchemaItem so that the traversal of items is controlled by the
ClauseVisitor itself, using the method visitor.traverse(item).
accept_visitor() methods can still be called directly but will not
do any traversal of child items. ClauseElement/SchemaItem now have a
configurable get_children() method to return the collection of child
elements for each parent object. This allows the full traversal of
items to be clear and unambiguous (as well as loggable), with an
easy method of limiting a traversal (just pass flags which are
picked up by appropriate get_children() methods).

.. change::
:tags: sql
:tickets:

the "else\_" parameter to the case statement now properly works when
set to zero.

.. change::
:tags: orm
:tickets:

the full featureset of the SelectResults extension has been merged
into a new set of methods available off of Query. These methods
all provide "generative" behavior, whereby the Query is copied
and a new one returned with additional criterion added.
The new methods include:

* filter() - applies select criterion to the query
* filter_by() - applies "by"-style criterion to the query
* avg() - return the avg() function on the given column
* join() - join to a property (or across a list of properties)
* outerjoin() - like join() but uses LEFT OUTER JOIN
* limit()/offset() - apply LIMIT/OFFSET range-based access
which applies limit/offset: session.query(Foo)[3:5]
* distinct() - apply DISTINCT
* list() - evaluate the criterion and return results

no incompatible changes have been made to Query's API and no methods
have been deprecated. Existing methods like select(), select_by(),
get(), get_by() all execute the query at once and return results
like they always did. join_to()/join_via() are still there although
the generative join()/outerjoin() methods are easier to use.

.. change::
:tags: orm
:tickets:

the return value for multiple mappers used with instances() now
returns a cartesian product of the requested list of mappers,
represented as a list of tuples. this corresponds to the documented
behavior. So that instances match up properly, the "uniquing" is
disabled when this feature is used.

.. change::
:tags: orm
:tickets:

Query has add_entity() and add_column() generative methods. these
will add the given mapper/class or ColumnElement to the query at
compile time, and apply them to the instances() method. the user is
responsible for constructing reasonable join conditions (otherwise
you can get full cartesian products). result set is the list of
tuples, non-uniqued.

.. change::
:tags: orm
:tickets:

strings and columns can also be sent to the \*args of instances()
where those exact result columns will be part of the result tuples.

.. change::
:tags: orm
:tickets:

a full select() construct can be passed to query.select() (which
worked anyway), but also query.selectfirst(), query.selectone()
which will be used as is (i.e. no query is compiled). works
similarly to sending the results to instances().

.. change::
:tags: orm
:tickets: 495

eager loading will not "aliasize" "order by" clauses that were
placed in the select statement by something other than the eager
loader itself, to fix possibility of dupe columns as illustrated in. however, this means you have to be more careful with
the columns placed in the "order by" of Query.select(), that you
have explicitly named them in your criterion (i.e. you can't rely on
the eager loader adding them in for you)

.. change::
:tags: orm
:tickets:

added a handy multi-use "identity_key()" method to Session, allowing
the generation of identity keys for primary key values, instances,
and rows, courtesy Daniel Miller

.. change::
:tags: orm
:tickets: 249

many-to-many table will be properly handled even for operations that
occur on the "backref" side of the operation

.. change::
:tags: orm
:tickets: 492

added "refresh-expire" cascade. allows refresh() and
expire() calls to propagate along relationships.

.. change::
:tags: orm
:tickets: 493

more fixes to polymorphic relations, involving proper lazy-clause
generation on many-to-one relationships to polymorphic mappers. also fixes to detection of "direction", more specific
targeting of columns that belong to the polymorphic union vs. those
that don't.

.. change::
:tags: orm
:tickets:

some fixes to relationship calcs when using "viewonly=True" to pull
in other tables into the join condition which aren't parent of the
relationship's parent/child mappings

.. change::
:tags: orm
:tickets:

flush fixes on cyclical-referential relationships that contain
references to other instances outside of the cyclical chain, when
some of the objects in the cycle are not actually part of the flush

.. change::
:tags: orm
:tickets: 500

put an aggressive check for "flushing object A with a collection of
B's, but you put a C in the collection" error condition - **even if
C is a subclass of B**, unless B's mapper loads polymorphically.
Otherwise, the collection will later load a "B" which should be a
"C" (since its not polymorphic) which breaks in bi-directional
relationships (i.e. C has its A, but A's backref will lazyload it as
a different instance of type "B") This check is going
to bite some of you who do this without issues, so the error message
will also document a flag "enable_typechecks=False" to disable this
checking. But be aware that bi-directional relationships in
particular become fragile without this check.

.. change::
:tags: extensions
:tickets: 472

options() method on SelectResults now implemented "generatively"
like the rest of the SelectResults methods. But
you're going to just use Query now anyway.

.. change::
:tags: extensions
:tickets:

query() method is added by assignmapper. this helps with
navigating to all the new generative methods on Query.

.. change::
:tags: ms-sql
:tickets:

removed seconds input on DATE column types (probably
should remove the time altogether)

.. change::
:tags: ms-sql
:tickets:

null values in float fields no longer raise errors

.. change::
:tags: ms-sql
:tickets:

LIMIT with OFFSET now raises an error (MS-SQL has no OFFSET support)

.. change::
:tags: ms-sql
:tickets: 509

added an facility to use the MSSQL type VARCHAR(max) instead of TEXT
for large unsized string fields. Use the new "text_as_varchar" to
turn it on.

.. change::
:tags: ms-sql
:tickets:

ORDER BY clauses without a LIMIT are now stripped in subqueries, as
MS-SQL forbids this usage

.. change::
:tags: ms-sql
:tickets: 480

cleanup of module importing code; specifiable DB-API module; more
explicit ordering of module preferences.

.. change::
:tags: oracle
:tickets:

got binary working for any size input ! cx_oracle works fine,
it was my fault as BINARY was being passed and not BLOB for
setinputsizes (also unit tests weren't even setting input sizes).

.. change::
:tags: oracle
:tickets:

also fixed CLOB read/write on a separate changeset.

.. change::
:tags: oracle
:tickets:

auto_setinputsizes defaults to True for Oracle, fixed cases where
it improperly propagated bad types.

.. change::
:tags: mysql
:tickets:

added a catchall \**kwargs to MSString, to help reflection of
obscure types (like "varchar() binary" in MS 4.0)

.. change::
:tags: mysql
:tickets:

added explicit MSTimeStamp type which takes effect when using
types.TIMESTAMP.

.. changelog::

:released: Thu Feb 22 2007

.. change::
:tags: sql
:tickets:

the value of "case_sensitive" defaults to True now, regardless of the
casing of the identifier, unless specifically set to False. this is
because the object might be label'ed as something else which does
contain mixed case, and propagating "case_sensitive=False" breaks that.
Other fixes to quoting when using labels and "fake" column objects

.. change::
:tags: sql
:tickets:

added a "supports_execution()" method to ClauseElement, so that
individual kinds of clauses can express if they are appropriate for
executing...such as, you can execute a "select", but not a "Table" or a
"Join".

.. change::
:tags: sql
:tickets:

fixed argument passing to straight textual execute() on engine,
connection. can handle \*args or a list instance for positional, \**kwargs
or a dict instance for named args, or a list of list or dicts to invoke
executemany()

.. change::
:tags: sql
:tickets:

small fix to BoundMetaData to accept unicode or string URLs

.. change::
:tags: sql
:tickets: 466

fixed named PrimaryKeyConstraint generation courtesy
andrija at gmail

.. change::
:tags: sql
:tickets: 464

fixed generation of CHECK constraints on columns

.. change::
:tags: sql
:tickets:

fixes to tometadata() operation to propagate Constraints at column and
table level

.. change::
:tags: oracle
:tickets: 436

when returning "rowid" as the ORDER BY column or in use with ROW_NUMBER
OVER, oracle dialect checks the selectable its being applied to and will
switch to table PK if not applicable, i.e. for a UNION. checking for
DISTINCT, GROUP BY (other places that rowid is invalid) still a TODO.
allows polymorphic mappings to function.

.. change::
:tags: oracle
:tickets:

sequences on a non-pk column will properly fire off on INSERT

.. change::
:tags: oracle
:tickets: 435

added PrefetchingResultProxy support to pre-fetch LOB columns when they
are known to be present, fixes

.. change::
:tags: oracle
:tickets: 379

implemented reflection of tables based on synonyms, including across
dblinks

.. change::
:tags: oracle
:tickets: 363

issues a log warning when a related table can't be reflected due to
certain permission errors

.. change::
:tags: mysql
:tickets:

fix to reflection on older DB's that might return array() type for
"show variables like" statements

.. change::
:tags: postgres
:tickets: 442

better reflection of sequences for alternate-schema Tables

.. change::
:tags: postgres
:tickets:

sequences on a non-pk column will properly fire off on INSERT

.. change::
:tags: postgres
:tickets: 460, 444

added PGInterval type, PGInet type

.. change::
:tags: mssql
:tickets: 419

preliminary support for pyodbc (Yay!)

.. change::
:tags: mssql
:tickets: 298

better support for NVARCHAR types added

.. change::
:tags: mssql
:tickets:

fix for commit logic on pymssql

.. change::
:tags: mssql
:tickets: 456

fix for query.get() with schema

.. change::
:tags: mssql
:tickets: 473

fix for non-integer relationships

.. change::
:tags: mssql
:tickets: 419

DB-API module now selectable at run-time

.. change::
:tags: tickets:422, 481, 415, mssql
:tickets:

now passes many more unit tests

.. change::
:tags: mssql
:tickets: 479

better unittest compatibility with ANSI functions

.. change::
:tags: mssql
:tickets: 415

improved support for implicit sequence PK columns with auto-insert

.. change::
:tags: mssql
:tickets: 371

fix for blank password in adodbapi

.. change::
:tags: mssql
:tickets: 481

fixes to get unit tests working with pyodbc

.. change::
:tags: mssql
:tickets:

fix to auto_identity_insert on db-url query

.. change::
:tags: mssql
:tickets:

added query_timeout to db-url query params. currently works only for
pymssql

.. change::
:tags: mssql
:tickets:

tested with pymssql 0.8.0 (which is now LGPL)

.. change::
:tags: orm, bugs
:tickets: 441, 448, 439

another refactoring to relationship calculation. Allows more accurate
ORM behavior with relationships from/to/between mappers, particularly
polymorphic mappers, also their usage with Query, SelectResults. tickets
include,,.

.. change::
:tags: orm, bugs
:tickets:

removed deprecated method of specifying custom collections on classes;
you must now use the "collection_class" option. the old way was
beginning to produce conflicts when people used assign_mapper(), which
now patches an "options" method, in conjunction with a relationship
named "options". (relationships take precedence over monkeypatched
assign_mapper methods).

.. change::
:tags: orm, bugs
:tickets: 454

extension() query option propagates to Mapper._instance() method so that
all loading-related methods get called

.. change::
:tags: orm, bugs
:tickets:

eager relation to an inheriting mapper won't fail if no rows returned for
the relationship.

.. change::
:tags: orm, bugs
:tickets: 486

eager relation loading bug fixed for eager relation on multiple
descendant classes

.. change::
:tags: orm, bugs
:tickets: 423

fix for very large topological sorts, courtesy ants.aasma at gmail

.. change::
:tags: orm, bugs
:tickets:

eager loading is slightly more strict about detecting "self-referential"
relationships, specifically between polymorphic mappers. this results in
an "eager degrade" to lazy loading.

.. change::
:tags: orm, bugs
:tickets: 449

improved support for complex queries embedded into "where" criterion for
query.select()

.. change::
:tags: orm, bugs
:tickets: 485

mapper options like eagerload(), lazyload(), deferred(), will work for
"synonym()" relationships

.. change::
:tags: orm, bugs
:tickets: 445

fixed bug where cascade operations incorrectly included deleted
collection items in the cascade

.. change::
:tags: orm, bugs
:tickets: 478

fixed relationship deletion error when one-to-many child item is moved
to a new parent in a single unit of work

.. change::
:tags: orm, bugs
:tickets:

fixed relationship deletion error where parent/child with a single
column as PK/FK on the child would raise a "blank out the primary key"
error, if manually deleted or "delete" cascade without "delete-orphan"
was used

.. change::
:tags: orm, bugs
:tickets:

fix to deferred so that load operation doesn't mistakenly occur when only
PK col attributes are set

.. change::
:tags: orm, enhancements
:tickets: 385

implemented foreign_keys argument to mapper. use in
conjunction with primaryjoin/secondaryjoin arguments to specify/override
foreign keys defined on the Table instance.

.. change::
:tags: orm, enhancements
:tickets:

contains_eager('foo') automatically implies eagerload('foo')

.. change::
:tags: orm, enhancements
:tickets:

added "alias" argument to contains_eager(). use it to specify the string
name or Alias instance of an alias used in the query for the eagerly
loaded child items. easier to use than "decorator"

.. change::
:tags: orm, enhancements
:tickets:

added "contains_alias()" option for result set mapping to an alias of
the mapped table

.. change::
:tags: orm, enhancements
:tickets: 468

added support for py2.5 "with" statement with SessionTransaction

.. change::
:tags: extensions
:tickets:

added distinct() method to SelectResults. generally should only make a
difference when using count().

.. change::
:tags: extensions
:tickets: 472

added options() method to SelectResults, equivalent to query.options()

.. change::
:tags: extensions
:tickets: 462

added optional __table_opts__ dictionary to ActiveMapper, will send kw
options to Table objects

.. change::
:tags: extensions
:tickets: 467

added selectfirst(), selectfirst_by() to assign_mapper

.. changelog::

:released: Tue Jan 23 2007

.. change::
:tags: general
:tickets:

global "insure"->"ensure" change. in US english "insure" is actually
largely interchangeable with "ensure" (so says the dictionary), so I'm not
completely illiterate, but its definitely sub-optimal to "ensure" which is
non-ambiguous.

.. change::
:tags: sql
:tickets:

added "fetchmany()" support to ResultProxy

.. change::
:tags: sql
:tickets:

added support for column "key" attribute to be usable in
row[<key>]/row.<key>

.. change::
:tags: sql
:tickets:

changed "BooleanExpression" to subclass from "BinaryExpression", so that
boolean expressions can also follow column-clause behaviors (i.e. label(),
etc).

.. change::
:tags: sql
:tickets:

trailing underscores are trimmed from func.<xxx> calls, such as func.if_()

.. change::
:tags: sql
:tickets:

fix to correlation of subqueries when the column list of the select
statement is constructed with individual calls to append_column(); this
fixes an ORM bug whereby nested select statements were not getting
correlated with the main select generated by the Query object.

.. change::
:tags: sql
:tickets:

another fix to subquery correlation so that a subquery which has only one
FROM element will *not* correlate that single element, since at least one
FROM element is required in a query.

.. change::
:tags: sql
:tickets: 414

default "timezone" setting is now False. this corresponds to Python's
datetime behavior as well as Postgres' timestamp/time types (which is the
only timezone-sensitive dialect at the moment)

.. change::
:tags: sql
:tickets:

the "op()" function is now treated as an "operation", rather than a
"comparison". the difference is, an operation produces a BinaryExpression
from which further operations can occur whereas comparison produces the
more restrictive BooleanExpression

.. change::
:tags: sql
:tickets:

trying to redefine a reflected primary key column as non-primary key raises
an error

.. change::
:tags: sql
:tickets:

type system slightly modified to support TypeDecorators that can be
overridden by the dialect (ok, that's not very clear, it allows the mssql
tweak below to be possible)

.. change::
:tags: mssql
:tickets:

added an NVarchar type (produces NVARCHAR), also MSUnicode which provides
Unicode-translation for the NVarchar regardless of dialect convert_unicode
setting.

.. change::
:tags: postgres
:tickets: 424

fix to the initial checkfirst for tables to take current schema into
account

.. change::
:tags: postgres
:tickets:

postgres has an optional "server_side_cursors=True" flag which will utilize
server side cursors. these are appropriate for fetching only partial
results and are necessary for working with very large unbounded result
sets. While we'd like this to be the default behavior, different
environments seem to have different results and the causes have not been
isolated so we are leaving the feature off by default for now. Uses an
apparently undocumented psycopg2 behavior recently discovered on the
psycopg mailing list.

.. change::
:tags: postgres
:tickets:

added "BIGSERIAL" support for postgres table with
PGBigInteger/autoincrement

.. change::
:tags: postgres
:tickets: 402

fixes to postgres reflection to better handle when schema names are
present; thanks to jason (at) ncsmags.com

.. change::
:tags: mysql
:tickets: 420

mysql is inconsistent with what kinds of quotes it uses in foreign keys
during a SHOW CREATE TABLE, reflection updated to accommodate for all three
styles

.. change::
:tags: mysql
:tickets: 418

mysql table create options work on a generic passthru now, i.e. Table(...,
mysql_engine='InnoDB', mysql_collate="latin1_german2_ci",
mysql_auto_increment="5", mysql_<somearg>...), helps

.. change::
:tags: firebird
:tickets: 408

order of constraint creation puts primary key first before all other
constraints; required for firebird, not a bad idea for others

.. change::
:tags: firebird
:tickets: 409

Firebird fix to autoload multifield foreign keys

.. change::
:tags: firebird
:tickets: 409

Firebird NUMERIC type properly handles a type without precision

.. change::
:tags: oracle
:tickets:

*slight* support for binary, but still need to figure out how to insert
reasonably large values (over 4K). requires auto_setinputsizes=True sent to
create_engine(), rows must be fully fetched individually, etc.

.. change::
:tags: orm
:tickets:

poked the first hole in the can of worms: saying
query.select_by(somerelationname=someinstance) will create the join of the
primary key columns represented by "somerelationname"'s mapper to the
actual primary key in "someinstance".

.. change::
:tags: orm
:tickets:

reworked how relations interact with "polymorphic" mappers, i.e. mappers
that have a select_table as well as polymorphic flags. better determination
of proper join conditions, interaction with user- defined join conditions,
and support for self-referential polymorphic mappers.

.. change::
:tags: orm
:tickets:

related to polymorphic mapping relations, some deeper error checking when
compiling relations, to detect an ambiguous "primaryjoin" in the case that
both sides of the relationship have foreign key references in the primary
join condition. also tightened down conditions used to locate "relation
direction", associating the "foreignkey" of the relationship with the
"primaryjoin"

.. change::
:tags: orm
:tickets:

a little bit of improvement to the concept of a "concrete" inheritance
mapping, though that concept is not well fleshed out yet (added test case
to support concrete mappers on top of a polymorphic base).

.. change::
:tags: orm
:tickets:

fix to "proxy=True" behavior on synonym()

.. change::
:tags: orm
:tickets: 427

fixed bug where delete-orphan basically didn't work with many-to-many
relationships, backref presence generally hid the symptom

.. change::
:tags: orm
:tickets:

added a mutex to the mapper compilation step. ive been reluctant to add any
kind of threading anything to SA but this is one spot that its really
needed since mappers are typically "global", and while their state does not
change during normal operation, the initial compilation step does modify
internal state significantly, and this step usually occurs not at
module-level initialization time (unless you call compile()) but at
first-request time

.. change::
:tags: orm
:tickets:

basic idea of "session.merge()" actually implemented. needs more testing.

.. change::
:tags: orm
:tickets:

added "compile_mappers()" function as a shortcut to compiling all mappers

.. change::
:tags: orm
:tickets:

fix to MapperExtension create_instance so that entity_name properly
associated with new instance

.. change::
:tags: orm
:tickets:

speed enhancements to ORM object instantiation, eager loading of rows

.. change::
:tags: orm
:tickets: 406

invalid options sent to 'cascade' string will raise an exception

.. change::
:tags: orm
:tickets: 407

fixed bug in mapper refresh/expire whereby eager loaders didn't properly
re-populate item lists

.. change::
:tags: orm
:tickets: 413

fix to post_update to ensure rows are updated even for non insert/delete
scenarios

.. change::
:tags: orm
:tickets: 412

added an error message if you actually try to modify primary key values on
an entity and then flush it

.. change::
:tags: extensions
:tickets: 426

added "validate=False" argument to assign_mapper, if True will ensure that
only mapped attributes are named

.. change::
:tags: extensions
:tickets:

assign_mapper gets "options", "instances" functions added (i.e.
MyClass.instances())

.. changelog::

:released: Fri Dec 15 2006

.. change::
:tags:
:tickets:

string-based FROM clauses fixed, i.e. select(..., from_obj=["sometext"])

.. change::
:tags:
:tickets:

fixes to passive_deletes flag, lazy=None (noload) flag

.. change::
:tags:
:tickets:

added example/docs for dealing with large collections

.. change::
:tags:
:tickets:

added object_session() method to sqlalchemy namespace

.. change::
:tags:
:tickets:

fixed QueuePool bug whereby its better able to reconnect to a database
that was not reachable (thanks to Sébastien Lelong), also fixed dispose()
method

.. change::
:tags:
:tickets: 396

patch that makes MySQL rowcount work correctly!

.. change::
:tags:
:tickets:

fix to MySQL catch of 2006/2014 errors to properly re-raise OperationalError
exception

.. changelog::