Add SelectBase.exists() method as it seems strange this is
not available already. The Exists construct itself does
not provide full SELECT-building capabilities so it makes
sense this should be used more like a scalar_subquery.
Make sure stream_results is getting set up when yield_per
is used, for 2.0 style statements as well. this was
hardcoded inside of Query.yield_per() and is now moved
to take place within QueryContext.
Change-Id: Icafcd4fd9b708772343d56edf40995c9e8f835d6
The operator changes are:
* `isfalse` is now `is_false`
* `isnot_distinct_from` is now `is_not_distinct_from`
* `istrue` is now `is_true`
* `notbetween` is now `not_between`
* `notcontains` is now `not_contains`
* `notendswith` is now `not_endswith`
* `notilike` is now `not_ilike`
* `notlike` is now `not_like`
* `notmatch` is now `not_match`
* `notstartswith` is now `not_startswith`
* `nullsfirst` is now `nulls_first`
* `nullslast` is now `nulls_last`
Because these are core operators, the internal migration strategy for this
change is to support legacy terms for an extended period of time -- if not
indefinitely -- but update all documentation, tutorials, and internal usage
to the new terms. The new terms are used to define the functions, and
the legacy terms have been deprecated into aliases of the new terms.
Fixes: #5435
Change-Id: Ifbd7cb1cdda5981990243c4fc4b4ff467dc132ac
Fixed structural compiler issue where some constructs such as MySQL /
PostgreSQL "on conflict / on duplicate key" would rely upon the state of
the :class:`_sql.Compiler` object being fixed against their statement as
the top level statement, which would fail in cases where those statements
are branched from a different context, such as a DDL construct linked to a
SQL statement.
Fixes: #5656
Change-Id: I568bf40adc7edcf72ea6c7fd6eb9d07790de189e
Improved support for column names that contain percent signs in the string,
including repaired issues involving anoymous labels that also embedded a
column name with a percent sign in it, as well as re-established support
for bound parameter names with percent signs embedded on the psycopg2
dialect, using a late-escaping process similar to that used by the
cx_Oracle dialect.
* Added new constructor for _anonymous_label() that ensures incoming
string tokens based on column or table names will have percent
signs escaped; abstracts away the format of the label.
* generalized cx_Oracle's quoted_bind_names facility into the compiler
itself, and leveraged this for the psycopg2 dialect's issue with
percent signs in names as well. the parameter substitution is now
integrated with compiler.construct_parameters() as well as the
recently reworked set_input_sizes(), reducing verbosity in the
cx_Oracle dialect.
Fixes: #5653
Change-Id: Ia2ad13ea68b4b0558d410026e5a33f5cb3fbab2c
Add support to ``FETCH {FIRST | NEXT} [ count ] {ROW | ROWS}
{ONLY | WITH TIES}`` in the select for the supported backends,
currently PostgreSQL, Oracle and MSSQL.
Fixes: #5576
Change-Id: Ibb5871a457c0555f82b37e354e7787d15575f1f7
It's better, the majority of these changes look more readable to me.
also found some docstrings that had formatting / quoting issues.
Change-Id: I582a45fde3a5648b2f36bab96bad56881321899b
This change includes mainly that the bracketed use within
select() is moved to positional, and keyword arguments are
removed from calls to the select() function. it does not
yet fully address other issues such as keyword arguments passed
to the table.select().
Additionally, allows False / None to both be considered
as "disable" for all of select.correlate(), select.correlate_except(),
query.correlate(), which establishes consistency with
passing of ``False`` for the legact select(correlate=False)
argument.
Change-Id: Ie6c6e6abfbd3d75d4c8de504c0cf0159e6999108
fixed an issue where even though the method claims to be
matching up columns positionally, it was failing on that by
looking in "keymap" based on string name.
Adds a new member to the _keymap recs MD_RESULT_MAP_INDEX
so that we can efficiently link from the generated keymap
back to the compiled._result_columns structure without
any ambiguity.
Fixes: #5559
Change-Id: Ie2fa9165c16625ef860ffac1190e00575e96761f
Fixed issue where the
:paramref:`_engine.Connection.execution_options.schema_translate_map`
feature would not take effect when the :meth:`_schema.Sequence.next_value`
function function for a :class:`_schema.Sequence` were used in the
:paramref:`_schema.Column.server_default` parameter and the create table
DDL were emitted.
Fixes: #5500
Change-Id: I74a9fa13d22749d06c8202669f9ea220d9d984d9
Remove lookup logic that attempts to locate a dialect for a type,
just use StrSQLTypeCompiler.
Cleaned up the internal ``str()`` for datatypes so that all types produce a
string representation without any dialect present, including that it works
for third-party dialect types without that dialect being present. The
string representation defaults to being the UPPERCASE name of that type
with nothing else.
Fixes: #4262
Change-Id: I02149e8a1ba1e7336149e962939b07ae0df83c6b
This is kind of a mixed bag of all kinds to help get us
to 1.4 betas. The documentation stuff is a work in
progress. Lots of other relatively small changes to
APIs and things. More commits will follow to continue
improving the documentation and transitioning to the
1.4/2.0 hybrid documentation. In particular some refinements
to Session usage models so that it can match Engine's
scoping / transactional patterns, and a decision to
start moving away from "subtransactions" completely.
* add select().from_statement() to produce FromStatement in an
ORM context
* begin referring to select() that has "plugins" for the few edge
cases where select() will have ORM-only behaviors
* convert dynamic.AppenderQuery to its own object that can use
select(), though at the moment it uses Query to support legacy
join calling forms.
* custom query classes for AppenderQuery are replaced by
do_orm_execute() hooks for custom actions, a separate gerrit
will document this
* add Session.get() to replace query.get()
* Deprecate session.begin->subtransaction. propose within the
test suite a hypothetical recipe for apps that rely on this
pattern
* introduce Session construction level context manager,
sessionmaker context manager, rewrite the whole top of the
session_transaction.rst documentation. Establish context manager
patterns for Session that are identical to engine
* ensure same begin_nested() / commit() behavior as engine
* devise all new "join into an external transaction" recipe,
add test support for it, add rules into Session so it
just works, write new docs. need to ensure this doesn't
break anything
* vastly reduce the verbosity of lots of session docs as
I dont think people read this stuff and it's difficult
to keep current in any case
* constructs like case(), with_only_columns() really need
to move to *columns, add a coercion rule to just change
these.
* docs need changes everywhere I look. in_() is not in
the Core tutorial? how do people even know about it?
Remove tons of cruft from Select docs, etc.
* build a system for common ORM options like populate_existing
and autoflush to populate from execution options.
* others?
Change-Id: Ia4bea0f804250e54d90b3884cf8aab8b66b82ecf
Several weeks of using the future_select() construct
has led to the proposal there be just one select() construct
again which features the new join() method, and otherwise accepts
both the 1.x and 2.x argument styles. This would make
migration simpler and reduce confusion.
However, confusion may be increased by the fact that select().join()
is different Current thinking is we may be better off
with a few hard behavioral changes to old and relatively unknown APIs
rather than trying to play both sides within two extremely similar
but subtly different APIs. At the moment, the .join() thing seems
to be the only behavioral change that occurs without the user
taking any explicit steps. Session.execute() will still
behave the old way as we are adding a future flag.
This change also adds the "future" flag to Session() and
session.execute(), so that interpretation of the incoming statement,
as well as that the new style result is returned, does not
occur for existing applications unless they add the use
of this flag.
The change in general is moving the "removed in 2.0" system
further along where we want the test suite to fully pass
even if the SQLALCHEMY_WARN_20 flag is set.
Get many tests to pass when SQLALCHEMY_WARN_20 is set; this
should be ongoing after this patch merges.
Improve the RemovedIn20 warning; these are all deprecated
"since" 1.4, so ensure that's what the messages read.
Make sure the inforamtion link is on all warnings.
Add deprecation warnings for parameters present and
add warnings to all FromClause.select() types of methods.
Fixes: #5379Fixes: #5284
Change-Id: I765a0b912b3dcd0e995426427d8bb7997cbffd51
References: #5159
Renamed the :meth:`_schema.Table.tometadata` method to
:meth:`_schema.Table.to_metadata`. The previous name remains with a
deprecation warning.
Updated the "decorate" utility function to support decoration
of functions that include non-builtins as default values.
Moves test for deprecated "databases" package into
test/dialect/test_deprecations.py
Fixes: #5413Fixes: #5426
Change-Id: I6ed899871c935f9e46360127c17ccb7cf97cea6e
A variety of caching issues found by running
all tests with statement caching turned on.
The cache system now has a more conservative approach where
any subclass of a SQL element will by default invalidate
the cache key unless it adds the flag inherit_cache=True
at the class level, or if it implements its own caching.
Add working caching to a few elements that were
omitted previously; fix some caching implementations
to suit lesser used edge cases such as json casts
and array slices.
Refine the way BaseCursorResult and CursorMetaData
interact with caching; to suit cases like Alembic
modifying table structures, don't cache the
cursor metadata if it were created against a
cursor.description using non-positional matching,
e.g. "select *". if a table re-ordered its columns
or added/removed, now that data is obsolete.
Additionally we have to adapt the cursor metadata
_keymap regardless of if we just processed
cursor.description, because if we ran against
a cached SQLCompiler we won't have the right
columns in _keymap.
Other refinements to how and when we do this
adaption as some weird cases
were exposed in the Postgresql dialect,
a text() construct that names just one column that
is not actually in the statement. Fixed that
also as it looks like a cut-and-paste artifact
that doesn't actually affect anything.
Various issues with re-use of compiled result maps
and cursor metadata in conjunction with tables being
changed, such as change in order of columns.
mappers can be cleared but the class remains, meaning
a mapper has to use itself as the cache key not the class.
lots of bound parameter / literal issues, due to Alembic
creating a straight subclass of bindparam that renders
inline directly. While we can update Alembic to not
do this, we have to assume other people might be doing
this, so bindparam() implements the inherit_cache=True
logic as well that was a bit involved.
turn on cache stats in logging.
Includes a fix to subqueryloader which moves all setup to
the create_row_processor() phase and elminates any storage
within the compiled context. This includes some changes
to create_row_processor() signature and a revising of the
technique used to determine if the loader can participate
in polymorphic queries, which is also applied to
selectinloading.
DML update.values() and ordered_values() now coerces the
keys as we have tests that pass an arbitrary class here
which only includes __clause_element__(), so the
key can't be cached unless it is coerced. this in turn
changed how composite attributes support bulk update
to use the standard approach of ClauseElement with
annotations that are parsed in the ORM context.
memory profiling successfully caught that the Session
from Query was getting passed into _statement_20()
so that was a big win for that test suite.
Apparently Compiler had .execute() and .scalar() methods
stuck on it, these date back to version 0.4 and there
was a single test in the PostgreSQL dialect tests
that exercised it for no apparent reason. Removed
these methods as well as the concept of a Compiler
holding onto a "bind".
Fixes: #5386
Change-Id: I990b43aab96b42665af1b2187ad6020bee778784
This patch contains a variety of ORM and expression layer
tweaks to support ORM constructs in select() statements,
without the 1.3.x requiremnt in Query that a full
_compile_context() + new select() is needed in order to
get a working statement object.
Includes such tweaks as the ability to implement
aliased class of an aliased class,
as we are looking to fully support ACs against subqueries,
as well as the ability to access anonymously-labeled
ColumnProperty expressions within subqueries by
naming the ".key" of the label after the property
key. Some tuning to query.join() as well
as ORMJoin internals to allow things to work more
smoothly.
Change-Id: Id810f485c5f7ed971529489b84694e02a3356d6d
Added support for "CREATE SEQUENCE" and full :class:`.Sequence` support for
Microsoft SQL Server. This removes the deprecated feature of using
:class:`.Sequence` objects to manipulate IDENTITY characteristics which
should now be performed using ``mssql_identity_start`` and
``mssql_identity_increment`` as documented at :ref:`mssql_identity`. The
change includes a new parameter :paramref:`.Sequence.data_type` to
accommodate SQL Server's choice of datatype, which for that backend
includes INTEGER and BIGINT. The default starting value for SQL Server's
version of :class:`.Sequence` has been set at 1; this default is now
emitted within the CREATE SEQUENCE DDL for all backends.
Fixes: #4235Fixes: #4633
Change-Id: I6aa55c441e8146c2f002e2e201a7f645e667b916
Added :meth:`.Select.with_hint` output to the generic SQL string that is
produced when calling ``str()`` on a statement. Previously, this clause
would be omitted under the assumption that it was dialect specific.
The hint text is presented within brackets to indicate the rendering
of such hints varies among backends.
Fixes: #5353
References: #4667
Change-Id: I01d97d6baa993e495519036ec7ecd5ae62856c16
This patch replaces the ORM execution flow with a
single pathway through Session.execute() for all queries,
including Core and ORM.
Currently included is full support for ORM Query,
Query.from_statement(), select(), as well as the
baked query and horizontal shard systems. Initial
changes have also been made to the dogpile caching
example, which like baked query makes use of a
new ORM-specific execution hook that replaces the
use of both QueryEvents.before_compile() as well
as Query._execute_and_instances() as the central
ORM interception hooks.
select() and Query() constructs alike can be passed to
Session.execute() where they will return ORM
results in a Results object. This API is currently
used internally by Query. Full support for
Session.execute()->results to behave in a fully
2.0 fashion will be in later changesets.
bulk update/delete with ORM support will also
be delivered via the update() and delete()
constructs, however these have not yet been adapted
to the new system and may follow in a subsequent
update.
Performance is also beginning to lag as of this
commit and some previous ones. It is hoped that
a few central functions such as the coercions
functions can be rewritten in C to re-gain
performance. Additionally, query caching
is now available and some subsequent patches
will attempt to cache more of the per-execution
work from the ORM layer, e.g. column getters
and adapters.
This patch also contains initial "turn on" of the
caching system enginewide via the query_cache_size
parameter to create_engine(). Still defaulting at
zero for "no caching". The caching system still
needs adjustments in order to gain adequate performance.
Change-Id: I047a7ebb26aa85dc01f6789fac2bff561dcd555d
Convert Query to do virtually all compile state computation
in the _compile_context() phase, and organize it all
such that a plain select() construct may also be used as the
source of information in order to generate ORM query state.
This makes it such that Query is not needed except for
its additional methods like from_self() which are all to
be deprecated.
The construction of ORM state will occur beyond the
caching boundary when the new execution model is integrated.
future select() gains a working join() and filter_by() method.
as we continue to rebase and merge each commit in the steps,
callcounts continue to bump around. will have to look at
the final result when it's all in.
References: #5159
References: #4705
References: #4639
References: #4871
References: #5010
Change-Id: I19e05b3424b07114cce6c439b05198ac47f7ac10
Added a "schema" parameter to the :func:`_expression.table` construct,
allowing ad-hoc table expressions to also include a schema name.
Pull request courtesy Dylan Modesitt.
Fixes: #5309Closes: #5310
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5310
Pull-request-sha: ce85681050
Change-Id: I32015d593e1ee1121c7426fbffdcc565d025fad1
As progress is made on the _future.Result, including breaking
it out such that DBAPI behaviors are local to specific
implementations, it becomes apparent that the Result object
is a functional superset of ResultProxy and that basic
operations like fetchone(), fetchall(), and fetchmany()
behave pretty much exactly the same way on the new object.
Reorganize things so that ResultProxy is now referred to
as LegacyCursorResult, which subclasses CursorResult
that represents the DBAPI-cursor version of Result,
making use of a multiple inheritance pattern so that
the functionality of Result is also available in non-DBAPI
contexts, as will be necessary for some ORM
patterns.
Additionally propose the composition system for Result
that will form the basis for ORM-alternative result
systems such as horizontal sharding and dogpile cache.
As ORM results will soon be coming directly from
instances of Result, these extensions will instead
build their own ResultFetchStrategies that perform
the special steps to create composed or cached
result sets.
Also considering at the moment not emitting deprecation
warnings for fetchXYZ() methods; the immediate issue
is Keystone tests are calling upon it, but as the
implementations here are proving to be not in any
kind of conflict with how Result works, there's
not too much issue leaving them around and deprecating
at some later point.
References: #5087
References: #4395Fixes: #4959
Change-Id: I8091919d45421e3f53029b8660427f844fee0228
Deprecate usage of ``DISTINCT ON`` in dialect other than PostgreSQL.
Previously this was silently ignored.
Deprecate old usage of string distinct in MySQL dialect
Fixes: #4002
Change-Id: I38fc64aef75e77748083c11d388ec831f161c9c9
Supercedes: If78fbb557c6f2cae637799c3fec2cbc5ac248aaf
Trying to see if by making the cache key memoized, we
still can have the older "identity" form of caching
which is the cheapest of all, at the same time as the
newer "cache key each time" version that is not nearly
as cheap; but still much cheaper than no caching at all.
Also needed is a per-execution update of _keymap when
we invoke from a cached select, so that Column objects
that are anonymous or otherwise adapted will match up.
this is analogous to the adaption of bound parameters
from the cache key.
Adds test coverage for the keymap / construct_params()
changes related to caching. Also hones performance
to a large extent for statement construction and
cache key generation.
Also includes a new memoized attribute
approach that vastly simplifies the previous approach
of "group_expirable_memoized_property" and finally
integrates cleanly with _clone(), _generate(), etc.
no more hardcoding of attributes is needed, as well
as that most _reset_memoization() calls are no longer
needed as the reset is inherent in a _generate() call;
this also has dramatic performance improvements.
Change-Id: I95c560ffcbfa30b26644999412fb6a385125f663
Add ability to literal compile a :class:`DateTime`, :class:`Date`
or :class:"Time" when using the string dialect for debugging purposes.
This change does not impact real dialect implementation that retain
their current behavior.
Fixes: #5052
Change-Id: Ia3fad2be905c6d35b0106b9a2388c7508f067e90
Revised the :paramref:`.Connection.execution_options.schema_translate_map`
feature such that the processing of the SQL statement to receive a specific
schema name occurs within the execution phase of the statement, rather than
at the compile phase. This is to support the statement being efficiently
cached. Previously, the current schema being rendered into the statement
for a particular run would be considered as part of the cache key itself,
meaning that for a run against hundreds of schemas, there would be hundreds
of cache keys, rendering the cache much less performant. The new behavior
is that the rendering is done in a similar manner as the "post compile"
rendering added in 1.4 as part of 🎫`4645`, 🎫`4808`.
Fixes: #5004
Change-Id: Ia5c89eb27cc8dc2c5b8e76d6c07c46290a7901b6
Continuation of I408e0b8be91fddd77cf279da97f55020871f75a9
- add an options() method to the base Generative construct.
this will be where ORM options can go
- Change Null, False_, True_ to be singletons, so that
we aren't instantiating them and having to use isinstance.
The previous issue with this was that they would produce dupe
labels in SELECT statements. Apply the duplicate column
logic, newly added in 1.4, to these objects as well as to
non-apply-labels SELECT statements in general as a means of
improving this.
- create a revised system for generating ClauseList compilation
constructs that simplfies up front creation to not actually
use ClauseList; a simple tuple is rendered by the compiler
using the same constrcution rules as what are used for
ClauseList but without creating the actual object. Apply
to Select, CompoundSelect, revise Update, Delete
- Select, CompoundSelect get an initial CompileState
implementation. All methods used only within compilation
are moved here
- refine update/insert/delete compile state to not require
an outside boolean
- refine and simplify Select._copy_internals
- rework bind(), which is going away, to not use some
of the internal traversal stuff
- remove "autocommit", "for_update" parameters from Select,
references #4643
- remove "autocommit" parameter from TextClause ,
references #4643
- add deprecation warnings for statement.execute(),
engine.execute(), statement.scalar(), engine.scalar().
Fixes: #5193
Change-Id: I04ca0152b046fd42c5054ba10f37e43fc6e5a57b
Targeting select / insert / update / delete, the goal
is to minimize overhead of construction and generative methods
so that only the raw arguments passed are handled. An interim
stage that converts the raw state into more compiler-ready state
is added, which is analogous to the ORM QueryContext which will
also be rolled in to be a similar concept, as is currently
being prototyped in I19e05b3424b07114cce6c439b05198ac47f7ac10.
the ORM update/delete BulkUD concept is also going to be rolled
onto this idea. So while the compiler-ready state object,
here called DMLState, looks a little thin, it's the
base of a bigger pattern that will allow for ORM functionality
to embed itself directly into the compiler, execution
context, and result set objects.
This change targets the DML objects, primarily focused on the
values() method which is the most complex process. The
work done by values() is minimized as much as possible
while still being able to create a cache key. Additional
computation is then offloaded to a new object ValuesState
that is handled by the compiler.
Architecturally, a big change here is that insert.values()
and update.values() will generate BindParameter objects for
the values now, which are then carefully received by crud.py
so that they generate the expected names. This is so that
the values() portion of these constructs is cacheable.
for the "multi-values" version of Insert, this is all skipped
and the plan right now is that a multi-values insert is
not worth caching (can always be revisited).
Using the
coercions system in values() also gets us nicer validation
for free, we can remove the NotAClauseElement thing from
schema, and we also now require scalar_subquery() is called
for an insert/update that uses a SELECT as a column value,
1.x deprecation path is added.
The traversal system is then applied to the DML objects
including tests so that they have traversal, cloning, and
cache key support. cloning is not a use case for DML however
having it present allows better validation of the structure
within the tests.
Special per-dialect DML is explicitly not cacheable at the moment,
more as a proof of concept that third party DML constructs can
exist as gracefully not-cacheable rather than producing an
incomplete cache key.
A few selected performance improvements have been added as well,
simplifying the immutabledict.union() method and adding
a new SQLCompiler function that can generate delimeter-separated
clauses like WHERE and ORDER BY without having to build
a ClauseList object at all. The use of ClauseList will
be removed from Select in an upcoming commit. Overall,
ClaustList is unnecessary for internal use and only adds
overhead to statement construction and will likely be removed
as much as possible except for explcit use of conjunctions like
and_() and or_().
Change-Id: I408e0b8be91fddd77cf279da97f55020871f75a9
Removed very antiquated logic that checks if __visit_name__
is a property. There's no need for this as the compiler can handle
switching between implementations. Convert _compile_dispatch()
to be fully inlined.
Change-Id: Ic0c7247c2d7dfed93a27f09250a8ed6352370764
This builds on cc718cccc0 which moved
RowProxy to Row, allowing Row to be more like a named tuple.
- KeyedTuple in ORM is replaced with Row
- ResultSetMetaData broken out into "simple" and "cursor" versions
for ORM and Core, as well as LegacyCursor version.
- Row now has _mapping attribute that supplies full mapping behavior.
Row and SimpleRow both have named tuple behavior otherwise.
LegacyRow has some mapping features on the tuple which emit
deprecation warnings (e.g. keys(), values(), etc). the biggest
change for mapping->tuple is the behavior of __contains__ which
moves from testing of "key in row" to "value in row".
- ResultProxy breaks into ResultProxy and FutureResult (interim),
the latter has the newer APIs. Made available to dialects
using execution options.
- internal reflection methods and most tests move off of implicit
Row mapping behavior and move to row._mapping, result.mappings()
method using future result
- a new strategy system for cursor handling replaces the various
subclasses of RowProxy
- some execution context adjustments. We will leave EC in but
refined things like get_result_proxy() and out parameter handling.
Dialects for 1.4 will need to adjust from get_result_proxy()
to get_result_cursor_strategy(), if they are using this method
- out parameter handling now accommodated by get_out_parameter_values()
EC method. Oracle changes for this. external dialect for
DB2 for example will also need to adjust for this.
- deprecate case_insensitive flag for engine / result, this
feature is not used
mapping-methods on Row are deprecated, and replaced with
Row._mapping.<meth>, including:
row.keys() -> use row._mapping.keys()
row.items() -> use row._mapping.items()
row.values() -> use row._mapping.values()
key in row -> use key in row._mapping
int in row -> use int < len(row)
Fixes: #4710Fixes: #4878
Change-Id: Ieb9085e9bcff564359095b754da9ae0af55679f0
Reorganization of Select() is the first major element
of the 2.0 restructuring. In order to start this we need
to first create the new Select constructor and apply legacy
elements to the old one. This in turn necessitates
starting up the RemovedIn20Warning concept which itself
need to refer to "sqlalchemy.future", so begin to establish
this basic framework. Additionally, update the
DML constructors with the newer no-keyword style. Remove
the use of the "pending deprecation" and fix Query.add_column()
deprecation which was not acting as deprecated.
Fixes: #4845Fixes: #4648
Change-Id: I0c7a22b2841a985e1c379a0bb6c94089aae6264c
Creating an :func:`.and_` or :func:`.or_` construct with no arguments or
empty ``*args`` will now emit a deprecation warning, as the SQL produced is
a no-op (i.e. it renders as a blank string). This behavior is considered to
be non-intuitive, so for empty or possibly empty :func:`.and_` or
:func:`.or_` constructs, an appropriate default boolean should be included,
such as ``and_(True, *args)`` or ``or_(False, *args)``. As has been the
case for many major versions of SQLAlchemy, these particular boolean
values will not render if the ``*args`` portion is non-empty.
As there are some internal cases where an empty and_() construct is used
in order to build an optional WHERE expression, a private
utility function is added to suit this use case.
Co-authored-by: Mike Bayer <mike_mp@zzzcomputing.com>
Fixes: #5054Closes: #5062
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5062
Pull-request-sha: 5ca2f27281
Change-Id: I599b9c8befa64d9a59a35ad7dd84ff400e3aa647
The "expanding IN" feature, which generates IN expressions at query
execution time which are based on the particular parameters associated with
the statement execution, is now used for all IN expressions made against
lists of literal values. This allows IN expressions to be fully cacheable
independently of the list of values being passed, and also includes support
for empty lists. For any scenario where the IN expression contains
non-literal SQL expressions, the old behavior of pre-rendering for each
position in the IN is maintained. The change also completes support for
expanding IN with tuples, where previously type-specific bind processors
weren't taking effect.
As part of this change, a more explicit separation between
"literal execute" and "post compile" bound parameters is being made;
as the "ansi bind rules" feature is rendering bound parameters
inline, as we now support "postcompile" generically, these should
be used here, however we have to render literal values at
execution time even for "expanding" parameters. new test fixtures
etc. are added to assert everything goes to the right place.
Fixes: #4645
Change-Id: Iaa2b7bfbfaaf5b80799ee17c9b8507293cba6ed1
Starting to go forward with the general idea of moving more
of Core / ORM construction into the compile phase. Bigger
initiatives like the refactor of Query will follow onto this.
Change-Id: I0f364d3182e21e32ed85ef34cfd11fd9d11cf653
Needed to add tests to ensure this label reference is handled
correctly, so also modified the exception message to
be more clear if someone has this error within distinct().
Change-Id: I6e685e46ae336596272d14366445ac224c18d92c
As of #4753 we allow duplicate columns. This creates some new
problems that there can be duplicate columns in a subquery
which are then not addressible on the outside because they
are ambiguous (Postgresql has this behavior at least). Additionally
it creates situations where we are making an anon label of an
anon label which is leaking into the query.
New logic for generating anon labels handles this situation and
also alters the .c collection
of a subquery such that we are only getting the first column
from the derived selectable that has that name, the subsequent ones
have a new deduping label with two underscores and are not exposed
in .c. The dedupe logic when rendering the columns will handle
duplicate label names for different columns, vs. the same column
repeated, as separate cases.
Fixes: #4892
Change-Id: I929fbd8da14bcc239e0481c24bbd9b5ce826e8fa
Deprecate query.instances() without a context
Deprecate string alias with contains_eager()
Deprecated the behavior by which a :class:`.Column` can be used as the key
in a result set row lookup, when that :class:`.Column` is not part of the
SQL selectable that is being selected; that is, it is only matched on name.
A deprecation warning is now emitted for this case. Various ORM use
cases, such as those involving :func:`.text` constructs, have been improved
so that this fallback logic is avoided in most cases.
Calling the :meth:`.Query.instances` method without passing a
:class:`.QueryContext` is deprecated. The original use case for this was
that a :class:`.Query` could yield ORM objects when given only the entities
to be selected as well as a DBAPI cursor object. However, for this to work
correctly there is essential metadata that is passed from a SQLAlchemy
:class:`.ResultProxy` that is derived from the mapped column expressions,
which comes originally from the :class:`.QueryContext`. To retrieve ORM
results from arbitrary SELECT statements, the :meth:`.Query.from_statement`
method should be used.
Note there is a small bump in test_zoomark because the
column._label is being calculated for each of those columns within
baseline_3_properties, as it is now part of the result map.
This label can't be calculated when the column is attached
to the table because it needs to have all the columns present
to do this correctly. Another approach here would be to
pre-load the _label before the test runs however the zoomark
tests don't have an easy place for this to happen and it's
not really worth it.
Fixes: #4877Fixes: #4719
Change-Id: I9bd29e72e6dce7c855651d69ba68d7383469acbc
as part of a larger series of changes to generalize row-tuples,
RowProxy becomes plain Row and is no longer a "proxy"; the
DBAPI row is now copied directly into the Row when constructed,
result handling occurs at once.
Subsequent changes will break out Row into a new version that
behaves fully a tuple.
Change-Id: I2ffa156afce5d21c38f28e54c3a531f361345dd5
generation is to be enhanced to include caching
functionality, so ensure that Query and all generative in Core
(e.g. select, DML etc) are using the same generations system.
Additionally, deprecate Select.append methods and state
Select methods independently of their append versions.
Mutability of expression objects is a special case only when
generating new objects during a visit.
Fixes: #4637
Change-Id: I3dfac00d5e0f710c833b236f7a0913e1ca24dde4
Characters that interfere with "pyformat" or "named" formats in bound
parameters, namely ``%, (, )`` and the space character, as well as a few
other typically undesirable characters, are stripped early for a
:func:`.bindparam` that is using an anonymized name, which is typically
generated automatically from a named column which itself includes these
characters in its name and does not use a ``.key``, so that they do not
interfere either with the SQLAlchemy compiler's use of string formatting or
with the driver-level parsing of the parameter, both of which could be
demonstrated before the fix. The change only applies to anonymized
parameter names that are generated and consumed internally, not end-user
defined names, so the change should have no impact on any existing code.
Applies in particular to the psycopg2 driver which does not otherwise quote
special parameter names, but also strips leading underscores to suit Oracle
(but not yet leading numbers, as some anon parameters are currently
entirely numeric/underscore based); Oracle in any case continues to quote
parameter names that include special characters.
Fixes: #4837
Change-Id: I21cb654c3e4ef786114160b8b4295242720bf3f9
Added new "post compile parameters" feature. This feature allows a
:func:`.bindparam` construct to have its value rendered into the SQL string
before being passed to the DBAPI driver, but after the compilation step,
using the "literal render" feature of the compiler. The immediate
rationale for this feature is to support LIMIT/OFFSET schemes that don't
work or perform well as bound parameters handled by the database driver,
while still allowing for SQLAlchemy SQL constructs to be cacheable in their
compiled form. The immediate targets for the new feature are the "TOP
N" clause used by SQL Server (and Sybase) which does not support a bound
parameter, as well as the "ROWNUM" and optional "FIRST_ROWS()" schemes used
by the Oracle dialect, the former of which has been known to perform better
without bound parameters and the latter of which does not support a bound
parameter. The feature builds upon the mechanisms first developed to
support "expanding" parameters for IN expressions. As part of this
feature, the Oracle ``use_binds_for_limits`` feature is turned on
unconditionally and this flag is now deprecated.
- adds limited support for "unique" bound parameters within
a text() construct.
- adds an additional int() check within the literal render
function of the Integer datatype and tests that non-int values
raise ValueError.
Fixes: #4808
Change-Id: Iace97d544d1a7351ee07db970c6bc06a19c712c6
Additional logic has been added such that certain SQL expressions which
typically wrap a single database column will use the name of that column as
their "anonymous label" name within a SELECT statement, potentially making
key-based lookups in result tuples more intutive. The primary example of
this is that of a CAST expression, e.g. ``CAST(table.colname AS INTEGER)``,
which will export its default name as "colname", rather than the usual
"anon_1" label, that is, ``CAST(table.colname AS INTEGER) AS colname``.
If the inner expression doesn't have a name, then the previous "anonymous
label" logic is used. When using SELECT statements that make use of
:meth:`.Select.apply_labels`, such as those emitted by the ORM, the
labeling logic will produce ``<tablename>_<inner column name>`` in the same
was as if the column were named alone. The logic applies right now to the
:func:`.cast` and :func:`.type_coerce` constructs as well as some
single-element boolean expressions.
Fixes: #4449
Change-Id: Ie3b73470e3bea53f2386cd86514cdc556491564e
Added support for composite (tuple) IN operators with SQLite, by rendering
the VALUES keyword for this backend. As other backends such as DB2 are
known to use the same syntax, the syntax is enabled in the base compiler
using a dialect-level flag ``tuple_in_values``. The change also includes
support for "empty IN tuple" expressions for SQLite when using "in_()"
between a tuple value and an empty set.
Fixes: #4766
Change-Id: I416e1af29b31d78f9ae06ec3c3a48ef6d6e813f5
The :func:`.select` construct and related constructs now allow for
duplication of column labels and columns themselves in the columns clause,
mirroring exactly how column expressions were passed in. This allows
the tuples returned by an executed result to match what was SELECTed
for in the first place, which is how the ORM :class:`.Query` works, so
this establishes better cross-compatibility between the two constructs.
Additionally, it allows column-positioning-sensitive structures such as
UNIONs (i.e. :class:`.CompoundSelect`) to be more intuitively constructed
in those cases where a particular column might appear in more than one
place. To support this change, the :class:`.ColumnCollection` has been
revised to support duplicate columns as well as to allow integer index
access.
Fixes: #4753
Change-Id: Ie09a8116f05c367995c1e43623c51e07971d3bf0
As part of the SQLAlchemy 2.0 migration project, a conceptual change has
been made to the role of the :class:`.SelectBase` class hierarchy,
which is the root of all "SELECT" statement constructs, in that they no
longer serve directly as FROM clauses, that is, they no longer subclass
:class:`.FromClause`. For end users, the change mostly means that any
placement of a :func:`.select` construct in the FROM clause of another
:func:`.select` requires first that it be wrapped in a subquery first,
which historically is through the use of the :meth:`.SelectBase.alias`
method, and is now also available through the use of
:meth:`.SelectBase.subquery`. This was usually a requirement in any
case since several databases don't accept unnamed SELECT subqueries
in their FROM clause in any case.
See the documentation in this change for lots more detail.
Fixes: #4617
Change-Id: I0f6174ee24b9a1a4529168e52e855e12abd60667
A major refactoring of all the functions handle all detection of
Core argument types as well as perform coercions into a new class hierarchy
based on "roles", each of which identify a syntactical location within a
SQL statement. In contrast to the ClauseElement hierarchy that identifies
"what" each object is syntactically, the SQLRole hierarchy identifies
the "where does it go" of each object syntactically. From this we define
a consistent type checking and coercion system that establishes well
defined behviors.
This is a breakout of the patch that is reorganizing select()
constructs to no longer be in the FromClause hierarchy.
Also includes a rename of as_scalar() into scalar_subquery(); deprecates
automatic coercion to scalar_subquery().
Partially-fixes: #4617
Change-Id: I26f1e78898693c6b99ef7ea2f4e7dfd0e8e1a1bd
Fully removed the behavior of strings passed directly as components of a
:func:`.select` or :class:`.Query` object being coerced to :func:`.text`
constructs automatically; the warning that has been emitted is now an
ArgumentError or in the case of order_by() / group_by() a CompileError.
This has emitted a warning since version 1.0 however its presence continues
to create concerns for the potential of mis-use of this behavior.
Note that public CVEs have been posted for order_by() / group_by() which
are resolved by this commit: CVE-2019-7164 CVE-2019-7548
Added "SQL phrase validation" to key DDL phrases that are accepted as plain
strings, including :paramref:`.ForeignKeyConstraint.on_delete`,
:paramref:`.ForeignKeyConstraint.on_update`,
:paramref:`.ExcludeConstraint.using`,
:paramref:`.ForeignKeyConstraint.initially`, for areas where a series of SQL
keywords only are expected.Any non-space characters that suggest the phrase
would need to be quoted will raise a :class:`.CompileError`. This change
is related to the series of changes committed as part of 🎫`4481`.
Fixed issue where using an uppercase name for an index type (e.g. GIST,
BTREE, etc. ) or an EXCLUDE constraint would treat it as an identifier to
be quoted, rather than rendering it as is. The new behavior converts these
types to lowercase and ensures they contain only valid SQL characters.
Quoting is applied to :class:`.Function` names, those which are usually but
not necessarily generated from the :attr:`.sql.func` construct, at compile
time if they contain illegal characters, such as spaces or punctuation. The
names are as before treated as case insensitive however, meaning if the
names contain uppercase or mixed case characters, that alone does not
trigger quoting. The case insensitivity is currently maintained for
backwards compatibility.
Fixes: #4481Fixes: #4473Fixes: #4467
Change-Id: Ib22a27d62930e24702e2f0f7c74a0473385a08eb
A large change throughout the library has ensured that all objects, parameters,
and behaviors which have been noted as deprecated or legacy now emit
``DeprecationWarning`` warnings when invoked. As the Python 3 interpreter now
defaults to displaying deprecation warnings, as well as that modern test suites
based on tools like tox and pytest tend to display deprecation warnings,
this change should make it easier to note what API features are obsolete.
See the notes added to the changelog and migration notes for further
details.
Fixes: #4393
Change-Id: If0ea11a1fc24f9a8029352eeadfc49a7a54c0a1b
Applied on top of a pure run of black -l 79 in
I7eda77fed3d8e73df84b3651fd6cfcfe858d4dc9, this set of changes
resolves all remaining flake8 conditions for those codes
we have enabled in setup.cfg.
Included are resolutions for all remaining flake8 issues
including shadowed builtins, long lines, import order, unused
imports, duplicate imports, and docstring issues.
Change-Id: I4f72d3ba1380dd601610ff80b8fb06a2aff8b0fe
This is a straight reformat run using black as is, with no edits
applied at all.
The black run will format code consistently, however in
some cases that are prevalent in SQLAlchemy code it produces
too-long lines. The too-long lines will be resolved in the
following commit that will resolve all remaining flake8 issues
including shadowed builtins, long lines, import order, unused
imports, duplicate imports, and docstring issues.
Change-Id: I7eda77fed3d8e73df84b3651fd6cfcfe858d4dc9
Mike Bayer