features that other objects like :class:`.Index` now do, that
the column expression may be specified as an arbitrary SQL
expression such as :obj:`.cast` or :obj:`.text`.
fixes#3454
"max_row_buffer" execution option for BufferedRowResultProxy
- also add documentation, changelog and version notes
- rework the max_row_buffer argument to be interpreted from
the execution options upfront when the BufferedRowResultProxy
is first initialized.
Suppose you have a model class with a primary key.
Base = declarative_base()
class User(Base):
id = Column(BigInteger, primary_key=True)
name = Column(String)
Previously, running
`bulk_update_mappings(User, {'id': 1, 'name': 'hello'})`
would emit the following:
```UPDATE users SET id=1, name='hello' WHERE id=1```
This is contrary to the stated behaviour, where primary keys are omitted
from the SET clause. Furthermore, this behaviour is harmful, as it
can cause the db engine to lock over-aggresively (at least in Postgres).
With this change, the emitted SQL is:
```UPDATE users SET name='hello' WHERE id=1```
objects that made use of the ``__clause_element__()`` method and
returned an object that was an ORM-mapped
:class:`.InstrumentedAttribute` and not explicitly a
:class:`.ColumnElement` would fail to be correctly
handled when passed as an expression to :meth:`.Session.query`.
The logic in 0.9 happened to succeed on this, so this use case is now
supported. fixes#3448
object would fail to accommodate the labeled SQL expression
in all cases, such that any SQL operation that made use of
:meth:`.Label.self_group` would use the original unadapted
expression. One effect of this would be that an ORM :func:`.aliased`
construct would not fully accommodate attributes mapped by
:obj:`.column_property`, such that the un-aliased table could
leak out when the property were used in some kinds of SQL
comparisons.
fixes#3445
psycopg2cffi dialect, in particular that the current 2.7.0 version
does not have native support for the JSONB type. The version detection
for psycopg2 features has been tuned into a specific sub-version
for psycopg2cffi. Additionally, test coverage has been enabled
for the full series of psycopg2 features under psycopg2cffi.
fixes#3439
When making baked query in classmethod of declarative base,
cls should be added in cache key.
@as_declarative
class Base(object):
@classmethod
def baked_query(cls):
return bakery(lambda: session.query(cls), (cls,))
:func:`.engine_from_config` were not being parsed correctly;
these included ``pool_threadlocal`` and the psycopg2 argument
``use_native_unicode``. fixes#3435
- add legacy_schema_aliasing config parsing for mssql
- move use_native_unicode config arg to the psycopg2 dialect
``legacy_schema_aliasing`` which when set to False will disable a
very old and obsolete behavior, that of the compiler's
attempt to turn all schema-qualified table names into alias names,
to work around old and no longer locatable issues where SQL
server could not parse a multi-part identifier name in all
circumstances. The behavior prevented more
sophisticated statements from working correctly, including those which
use hints, as well as CRUD statements that embed correlated SELECT
statements. Rather than continue to repair the feature to work
with more complex statements, it's better to just disable it
as it should no longer be needed for any modern SQL server
version. The flag defaults to True for the 1.0.x series, leaving
current behavior unchanged for this version series. In the 1.1
series, it will default to False. For the 1.0 series,
when not set to either value explicitly, a warning is emitted
when a schema-qualified table is first used in a statement, which
suggests that the flag be set to False for all modern SQL Server
versions.
fixes#3424fixes#3430
:meth:`.URL.get_dialect` method will continue to return the
ultimate :class:`.Dialect` object when a dialect plugin is used,
without the need for the caller to be aware of the
:meth:`.Dialect.get_dialect_cls` method.
reference #3379
Sebastian Bank