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# engine/reflection.py
# Copyright (C) 2005-2024 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
"""Provides an abstraction for obtaining database schema information.
Usage Notes:
Here are some general conventions when accessing the low level inspector
methods such as get_table_names, get_columns, etc.
1. Inspector methods return lists of dicts in most cases for the following
reasons:
* They're both standard types that can be serialized.
* Using a dict instead of a tuple allows easy expansion of attributes.
* Using a list for the outer structure maintains order and is easy to work
with (e.g. list comprehension [d['name'] for d in cols]).
2. Records that contain a name, such as the column name in a column record
use the key 'name'. So for most return values, each record will have a
'name' attribute..
"""
from __future__ import annotations
import contextlib
from dataclasses import dataclass
from enum import auto
from enum import Flag
from enum import unique
from typing import Any
from typing import Callable
from typing import Collection
from typing import Dict
from typing import Generator
from typing import Iterable
from typing import List
from typing import Optional
from typing import Sequence
from typing import Set
from typing import Tuple
from typing import TYPE_CHECKING
from typing import TypeVar
from typing import Union
from .base import Connection
from .base import Engine
from .. import exc
from .. import inspection
from .. import sql
from .. import util
from ..sql import operators
from ..sql import schema as sa_schema
from ..sql.cache_key import _ad_hoc_cache_key_from_args
from ..sql.elements import TextClause
from ..sql.type_api import TypeEngine
from ..sql.visitors import InternalTraversal
from ..util import topological
from ..util.typing import final
if TYPE_CHECKING:
from .interfaces import Dialect
from .interfaces import ReflectedCheckConstraint
from .interfaces import ReflectedColumn
from .interfaces import ReflectedForeignKeyConstraint
from .interfaces import ReflectedIndex
from .interfaces import ReflectedPrimaryKeyConstraint
from .interfaces import ReflectedTableComment
from .interfaces import ReflectedUniqueConstraint
from .interfaces import TableKey
_R = TypeVar("_R")
@util.decorator
def cache(
fn: Callable[..., _R],
self: Dialect,
con: Connection,
*args: Any,
**kw: Any,
) -> _R:
info_cache = kw.get("info_cache", None)
if info_cache is None:
return fn(self, con, *args, **kw)
exclude = {"info_cache", "unreflectable"}
key = (
fn.__name__,
tuple(a for a in args if isinstance(a, str)),
tuple((k, v) for k, v in kw.items() if k not in exclude),
)
ret: _R = info_cache.get(key)
if ret is None:
ret = fn(self, con, *args, **kw)
info_cache[key] = ret
return ret
def flexi_cache(
*traverse_args: Tuple[str, InternalTraversal]
) -> Callable[[Callable[..., _R]], Callable[..., _R]]:
@util.decorator
def go(
fn: Callable[..., _R],
self: Dialect,
con: Connection,
*args: Any,
**kw: Any,
) -> _R:
info_cache = kw.get("info_cache", None)
if info_cache is None:
return fn(self, con, *args, **kw)
key = _ad_hoc_cache_key_from_args((fn.__name__,), traverse_args, args)
ret: _R = info_cache.get(key)
if ret is None:
ret = fn(self, con, *args, **kw)
info_cache[key] = ret
return ret
return go
@unique
class ObjectKind(Flag):
"""Enumerator that indicates which kind of object to return when calling
the ``get_multi`` methods.
This is a Flag enum, so custom combinations can be passed. For example,
to reflect tables and plain views ``ObjectKind.TABLE | ObjectKind.VIEW``
may be used.
.. note::
Not all dialect may support all kind of object. If a dialect does
not support a particular object an empty dict is returned.
In case a dialect supports an object, but the requested method
is not applicable for the specified kind the default value
will be returned for each reflected object. For example reflecting
check constraints of view return a dict with all the views with
empty lists as values.
"""
TABLE = auto()
"Reflect table objects"
VIEW = auto()
"Reflect plain view objects"
MATERIALIZED_VIEW = auto()
"Reflect materialized view object"
ANY_VIEW = VIEW | MATERIALIZED_VIEW
"Reflect any kind of view objects"
ANY = TABLE | VIEW | MATERIALIZED_VIEW
"Reflect all type of objects"
@unique
class ObjectScope(Flag):
"""Enumerator that indicates which scope to use when calling
the ``get_multi`` methods.
"""
DEFAULT = auto()
"Include default scope"
TEMPORARY = auto()
"Include only temp scope"
ANY = DEFAULT | TEMPORARY
"Include both default and temp scope"
@inspection._self_inspects
class Inspector(inspection.Inspectable["Inspector"]):
"""Performs database schema inspection.
The Inspector acts as a proxy to the reflection methods of the
:class:`~sqlalchemy.engine.interfaces.Dialect`, providing a
consistent interface as well as caching support for previously
fetched metadata.
A :class:`_reflection.Inspector` object is usually created via the
:func:`_sa.inspect` function, which may be passed an
:class:`_engine.Engine`
or a :class:`_engine.Connection`::
from sqlalchemy import inspect, create_engine
engine = create_engine('...')
insp = inspect(engine)
Where above, the :class:`~sqlalchemy.engine.interfaces.Dialect` associated
with the engine may opt to return an :class:`_reflection.Inspector`
subclass that
provides additional methods specific to the dialect's target database.
"""
bind: Union[Engine, Connection]
engine: Engine
_op_context_requires_connect: bool
dialect: Dialect
info_cache: Dict[Any, Any]
@util.deprecated(
"1.4",
"The __init__() method on :class:`_reflection.Inspector` "
"is deprecated and "
"will be removed in a future release. Please use the "
":func:`.sqlalchemy.inspect` "
"function on an :class:`_engine.Engine` or "
":class:`_engine.Connection` "
"in order to "
"acquire an :class:`_reflection.Inspector`.",
)
def __init__(self, bind: Union[Engine, Connection]):
"""Initialize a new :class:`_reflection.Inspector`.
:param bind: a :class:`~sqlalchemy.engine.Connection`,
which is typically an instance of
:class:`~sqlalchemy.engine.Engine` or
:class:`~sqlalchemy.engine.Connection`.
For a dialect-specific instance of :class:`_reflection.Inspector`, see
:meth:`_reflection.Inspector.from_engine`
"""
self._init_legacy(bind)
@classmethod
def _construct(
cls, init: Callable[..., Any], bind: Union[Engine, Connection]
) -> Inspector:
if hasattr(bind.dialect, "inspector"):
cls = bind.dialect.inspector
self = cls.__new__(cls)
init(self, bind)
return self
def _init_legacy(self, bind: Union[Engine, Connection]) -> None:
if hasattr(bind, "exec_driver_sql"):
self._init_connection(bind) # type: ignore[arg-type]
else:
self._init_engine(bind)
def _init_engine(self, engine: Engine) -> None:
self.bind = self.engine = engine
engine.connect().close()
self._op_context_requires_connect = True
self.dialect = self.engine.dialect
self.info_cache = {}
def _init_connection(self, connection: Connection) -> None:
self.bind = connection
self.engine = connection.engine
self._op_context_requires_connect = False
self.dialect = self.engine.dialect
self.info_cache = {}
def clear_cache(self) -> None:
"""reset the cache for this :class:`.Inspector`.
Inspection methods that have data cached will emit SQL queries
when next called to get new data.
.. versionadded:: 2.0
"""
self.info_cache.clear()
@classmethod
@util.deprecated(
"1.4",
"The from_engine() method on :class:`_reflection.Inspector` "
"is deprecated and "
"will be removed in a future release. Please use the "
":func:`.sqlalchemy.inspect` "
"function on an :class:`_engine.Engine` or "
":class:`_engine.Connection` "
"in order to "
"acquire an :class:`_reflection.Inspector`.",
)
def from_engine(cls, bind: Engine) -> Inspector:
"""Construct a new dialect-specific Inspector object from the given
engine or connection.
:param bind: a :class:`~sqlalchemy.engine.Connection`
or :class:`~sqlalchemy.engine.Engine`.
This method differs from direct a direct constructor call of
:class:`_reflection.Inspector` in that the
:class:`~sqlalchemy.engine.interfaces.Dialect` is given a chance to
provide a dialect-specific :class:`_reflection.Inspector` instance,
which may
provide additional methods.
See the example at :class:`_reflection.Inspector`.
"""
return cls._construct(cls._init_legacy, bind)
@inspection._inspects(Engine)
def _engine_insp(bind: Engine) -> Inspector: # type: ignore[misc]
return Inspector._construct(Inspector._init_engine, bind)
@inspection._inspects(Connection)
def _connection_insp(bind: Connection) -> Inspector: # type: ignore[misc]
return Inspector._construct(Inspector._init_connection, bind)
@contextlib.contextmanager
def _operation_context(self) -> Generator[Connection, None, None]:
"""Return a context that optimizes for multiple operations on a single
transaction.
This essentially allows connect()/close() to be called if we detected
that we're against an :class:`_engine.Engine` and not a
:class:`_engine.Connection`.
"""
conn: Connection
if self._op_context_requires_connect:
conn = self.bind.connect() # type: ignore[union-attr]
else:
conn = self.bind # type: ignore[assignment]
try:
yield conn
finally:
if self._op_context_requires_connect:
conn.close()
@contextlib.contextmanager
def _inspection_context(self) -> Generator[Inspector, None, None]:
"""Return an :class:`_reflection.Inspector`
from this one that will run all
operations on a single connection.
"""
with self._operation_context() as conn:
sub_insp = self._construct(self.__class__._init_connection, conn)
sub_insp.info_cache = self.info_cache
yield sub_insp
@property
def default_schema_name(self) -> Optional[str]:
"""Return the default schema name presented by the dialect
for the current engine's database user.
E.g. this is typically ``public`` for PostgreSQL and ``dbo``
for SQL Server.
"""
return self.dialect.default_schema_name
def get_schema_names(self, **kw: Any) -> List[str]:
r"""Return all schema names.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
"""
with self._operation_context() as conn:
return self.dialect.get_schema_names(
conn, info_cache=self.info_cache, **kw
)
def get_table_names(
self, schema: Optional[str] = None, **kw: Any
) -> List[str]:
r"""Return all table names within a particular schema.
The names are expected to be real tables only, not views.
Views are instead returned using the
:meth:`_reflection.Inspector.get_view_names` and/or
:meth:`_reflection.Inspector.get_materialized_view_names`
methods.
:param schema: Schema name. If ``schema`` is left at ``None``, the
database's default schema is
used, else the named schema is searched. If the database does not
support named schemas, behavior is undefined if ``schema`` is not
passed as ``None``. For special quoting, use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
.. seealso::
:meth:`_reflection.Inspector.get_sorted_table_and_fkc_names`
:attr:`_schema.MetaData.sorted_tables`
"""
with self._operation_context() as conn:
return self.dialect.get_table_names(
conn, schema, info_cache=self.info_cache, **kw
)
def has_table(
self, table_name: str, schema: Optional[str] = None, **kw: Any
) -> bool:
r"""Return True if the backend has a table, view, or temporary
table of the given name.
:param table_name: name of the table to check
:param schema: schema name to query, if not the default schema.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
.. versionadded:: 1.4 - the :meth:`.Inspector.has_table` method
replaces the :meth:`_engine.Engine.has_table` method.
.. versionchanged:: 2.0:: :meth:`.Inspector.has_table` now formally
supports checking for additional table-like objects:
* any type of views (plain or materialized)
* temporary tables of any kind
Previously, these two checks were not formally specified and
different dialects would vary in their behavior. The dialect
testing suite now includes tests for all of these object types
and should be supported by all SQLAlchemy-included dialects.
Support among third party dialects may be lagging, however.
"""
with self._operation_context() as conn:
return self.dialect.has_table(
conn, table_name, schema, info_cache=self.info_cache, **kw
)
def has_sequence(
self, sequence_name: str, schema: Optional[str] = None, **kw: Any
) -> bool:
r"""Return True if the backend has a sequence with the given name.
:param sequence_name: name of the sequence to check
:param schema: schema name to query, if not the default schema.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
.. versionadded:: 1.4
"""
with self._operation_context() as conn:
return self.dialect.has_sequence(
conn, sequence_name, schema, info_cache=self.info_cache, **kw
)
def has_index(
self,
table_name: str,
index_name: str,
schema: Optional[str] = None,
**kw: Any,
) -> bool:
r"""Check the existence of a particular index name in the database.
:param table_name: the name of the table the index belongs to
:param index_name: the name of the index to check
:param schema: schema name to query, if not the default schema.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
.. versionadded:: 2.0
"""
with self._operation_context() as conn:
return self.dialect.has_index(
conn,
table_name,
index_name,
schema,
info_cache=self.info_cache,
**kw,
)
def has_schema(self, schema_name: str, **kw: Any) -> bool:
r"""Return True if the backend has a schema with the given name.
:param schema_name: name of the schema to check
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
.. versionadded:: 2.0
"""
with self._operation_context() as conn:
return self.dialect.has_schema(
conn, schema_name, info_cache=self.info_cache, **kw
)
def get_sorted_table_and_fkc_names(
self,
schema: Optional[str] = None,
**kw: Any,
) -> List[Tuple[Optional[str], List[Tuple[str, Optional[str]]]]]:
r"""Return dependency-sorted table and foreign key constraint names in
referred to within a particular schema.
This will yield 2-tuples of
``(tablename, [(tname, fkname), (tname, fkname), ...])``
consisting of table names in CREATE order grouped with the foreign key
constraint names that are not detected as belonging to a cycle.
The final element
will be ``(None, [(tname, fkname), (tname, fkname), ..])``
which will consist of remaining
foreign key constraint names that would require a separate CREATE
step after-the-fact, based on dependencies between tables.
:param schema: schema name to query, if not the default schema.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
.. seealso::
:meth:`_reflection.Inspector.get_table_names`
:func:`.sort_tables_and_constraints` - similar method which works
with an already-given :class:`_schema.MetaData`.
"""
return [
(
table_key[1] if table_key else None,
[(tname, fks) for (_, tname), fks in fk_collection],
)
for (
table_key,
fk_collection,
) in self.sort_tables_on_foreign_key_dependency(
consider_schemas=(schema,)
)
]
def sort_tables_on_foreign_key_dependency(
self,
consider_schemas: Collection[Optional[str]] = (None,),
**kw: Any,
) -> List[
Tuple[
Optional[Tuple[Optional[str], str]],
List[Tuple[Tuple[Optional[str], str], Optional[str]]],
]
]:
r"""Return dependency-sorted table and foreign key constraint names
referred to within multiple schemas.
This method may be compared to
:meth:`.Inspector.get_sorted_table_and_fkc_names`, which
works on one schema at a time; here, the method is a generalization
that will consider multiple schemas at once including that it will
resolve for cross-schema foreign keys.
.. versionadded:: 2.0
"""
SchemaTab = Tuple[Optional[str], str]
tuples: Set[Tuple[SchemaTab, SchemaTab]] = set()
remaining_fkcs: Set[Tuple[SchemaTab, Optional[str]]] = set()
fknames_for_table: Dict[SchemaTab, Set[Optional[str]]] = {}
tnames: List[SchemaTab] = []
for schname in consider_schemas:
schema_fkeys = self.get_multi_foreign_keys(schname, **kw)
tnames.extend(schema_fkeys)
for (_, tname), fkeys in schema_fkeys.items():
fknames_for_table[(schname, tname)] = {
fk["name"] for fk in fkeys
}
for fkey in fkeys:
if (
tname != fkey["referred_table"]
or schname != fkey["referred_schema"]
):
tuples.add(
(
(
fkey["referred_schema"],
fkey["referred_table"],
),
(schname, tname),
)
)
try:
candidate_sort = list(topological.sort(tuples, tnames))
except exc.CircularDependencyError as err:
edge: Tuple[SchemaTab, SchemaTab]
for edge in err.edges:
tuples.remove(edge)
remaining_fkcs.update(
(edge[1], fkc) for fkc in fknames_for_table[edge[1]]
)
candidate_sort = list(topological.sort(tuples, tnames))
ret: List[
Tuple[Optional[SchemaTab], List[Tuple[SchemaTab, Optional[str]]]]
]
ret = [
(
(schname, tname),
[
((schname, tname), fk)
for fk in fknames_for_table[(schname, tname)].difference(
name for _, name in remaining_fkcs
)
],
)
for (schname, tname) in candidate_sort
]
return ret + [(None, list(remaining_fkcs))]
def get_temp_table_names(self, **kw: Any) -> List[str]:
r"""Return a list of temporary table names for the current bind.
This method is unsupported by most dialects; currently
only Oracle, PostgreSQL and SQLite implements it.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
"""
with self._operation_context() as conn:
return self.dialect.get_temp_table_names(
conn, info_cache=self.info_cache, **kw
)
def get_temp_view_names(self, **kw: Any) -> List[str]:
r"""Return a list of temporary view names for the current bind.
This method is unsupported by most dialects; currently
only PostgreSQL and SQLite implements it.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
"""
with self._operation_context() as conn:
return self.dialect.get_temp_view_names(
conn, info_cache=self.info_cache, **kw
)
def get_table_options(
self, table_name: str, schema: Optional[str] = None, **kw: Any
) -> Dict[str, Any]:
r"""Return a dictionary of options specified when the table of the
given name was created.
This currently includes some options that apply to MySQL and Oracle
tables.
:param table_name: string name of the table. For special quoting,
use :class:`.quoted_name`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dict with the table options. The returned keys depend on the
dialect in use. Each one is prefixed with the dialect name.
.. seealso:: :meth:`Inspector.get_multi_table_options`
"""
with self._operation_context() as conn:
return self.dialect.get_table_options(
conn, table_name, schema, info_cache=self.info_cache, **kw
)
def get_multi_table_options(
self,
schema: Optional[str] = None,
filter_names: Optional[Sequence[str]] = None,
kind: ObjectKind = ObjectKind.TABLE,
scope: ObjectScope = ObjectScope.DEFAULT,
**kw: Any,
) -> Dict[TableKey, Dict[str, Any]]:
r"""Return a dictionary of options specified when the tables in the
given schema were created.
The tables can be filtered by passing the names to use to
``filter_names``.
This currently includes some options that apply to MySQL and Oracle
tables.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param filter_names: optionally return information only for the
objects listed here.
:param kind: a :class:`.ObjectKind` that specifies the type of objects
to reflect. Defaults to ``ObjectKind.TABLE``.
:param scope: a :class:`.ObjectScope` that specifies if options of
default, temporary or any tables should be reflected.
Defaults to ``ObjectScope.DEFAULT``.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary where the keys are two-tuple schema,table-name
and the values are dictionaries with the table options.
The returned keys in each dict depend on the
dialect in use. Each one is prefixed with the dialect name.
The schema is ``None`` if no schema is provided.
.. versionadded:: 2.0
.. seealso:: :meth:`Inspector.get_table_options`
"""
with self._operation_context() as conn:
res = self.dialect.get_multi_table_options(
conn,
schema=schema,
filter_names=filter_names,
kind=kind,
scope=scope,
info_cache=self.info_cache,
**kw,
)
return dict(res)
def get_view_names(
self, schema: Optional[str] = None, **kw: Any
) -> List[str]:
r"""Return all non-materialized view names in `schema`.
:param schema: Optional, retrieve names from a non-default schema.
For special quoting, use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
.. versionchanged:: 2.0 For those dialects that previously included
the names of materialized views in this list (currently PostgreSQL),
this method no longer returns the names of materialized views.
the :meth:`.Inspector.get_materialized_view_names` method should
be used instead.
.. seealso::
:meth:`.Inspector.get_materialized_view_names`
"""
with self._operation_context() as conn:
return self.dialect.get_view_names(
conn, schema, info_cache=self.info_cache, **kw
)
def get_materialized_view_names(
self, schema: Optional[str] = None, **kw: Any
) -> List[str]:
r"""Return all materialized view names in `schema`.
:param schema: Optional, retrieve names from a non-default schema.
For special quoting, use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
.. versionadded:: 2.0
.. seealso::
:meth:`.Inspector.get_view_names`
"""
with self._operation_context() as conn:
return self.dialect.get_materialized_view_names(
conn, schema, info_cache=self.info_cache, **kw
)
def get_sequence_names(
self, schema: Optional[str] = None, **kw: Any
) -> List[str]:
r"""Return all sequence names in `schema`.
:param schema: Optional, retrieve names from a non-default schema.
For special quoting, use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
"""
with self._operation_context() as conn:
return self.dialect.get_sequence_names(
conn, schema, info_cache=self.info_cache, **kw
)
def get_view_definition(
self, view_name: str, schema: Optional[str] = None, **kw: Any
) -> str:
r"""Return definition for the plain or materialized view called
``view_name``.
:param view_name: Name of the view.
:param schema: Optional, retrieve names from a non-default schema.
For special quoting, use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
"""
with self._operation_context() as conn:
return self.dialect.get_view_definition(
conn, view_name, schema, info_cache=self.info_cache, **kw
)
def get_columns(
self, table_name: str, schema: Optional[str] = None, **kw: Any
) -> List[ReflectedColumn]:
r"""Return information about columns in ``table_name``.
Given a string ``table_name`` and an optional string ``schema``,
return column information as a list of :class:`.ReflectedColumn`.
:param table_name: string name of the table. For special quoting,
use :class:`.quoted_name`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: list of dictionaries, each representing the definition of
a database column.
.. seealso:: :meth:`Inspector.get_multi_columns`.
"""
with self._operation_context() as conn:
col_defs = self.dialect.get_columns(
conn, table_name, schema, info_cache=self.info_cache, **kw
)
if col_defs:
self._instantiate_types([col_defs])
return col_defs
def _instantiate_types(
self, data: Iterable[List[ReflectedColumn]]
) -> None:
# make this easy and only return instances for coltype
for col_defs in data:
for col_def in col_defs:
coltype = col_def["type"]
if not isinstance(coltype, TypeEngine):
col_def["type"] = coltype()
def get_multi_columns(
self,
schema: Optional[str] = None,
filter_names: Optional[Sequence[str]] = None,
kind: ObjectKind = ObjectKind.TABLE,
scope: ObjectScope = ObjectScope.DEFAULT,
**kw: Any,
) -> Dict[TableKey, List[ReflectedColumn]]:
r"""Return information about columns in all objects in the given
schema.
The objects can be filtered by passing the names to use to
``filter_names``.
For each table the value is a list of :class:`.ReflectedColumn`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param filter_names: optionally return information only for the
objects listed here.
:param kind: a :class:`.ObjectKind` that specifies the type of objects
to reflect. Defaults to ``ObjectKind.TABLE``.
:param scope: a :class:`.ObjectScope` that specifies if columns of
default, temporary or any tables should be reflected.
Defaults to ``ObjectScope.DEFAULT``.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary where the keys are two-tuple schema,table-name
and the values are list of dictionaries, each representing the
definition of a database column.
The schema is ``None`` if no schema is provided.
.. versionadded:: 2.0
.. seealso:: :meth:`Inspector.get_columns`
"""
with self._operation_context() as conn:
table_col_defs = dict(
self.dialect.get_multi_columns(
conn,
schema=schema,
filter_names=filter_names,
kind=kind,
scope=scope,
info_cache=self.info_cache,
**kw,
)
)
self._instantiate_types(table_col_defs.values())
return table_col_defs
def get_pk_constraint(
self, table_name: str, schema: Optional[str] = None, **kw: Any
) -> ReflectedPrimaryKeyConstraint:
r"""Return information about primary key constraint in ``table_name``.
Given a string ``table_name``, and an optional string `schema`, return
primary key information as a :class:`.ReflectedPrimaryKeyConstraint`.
:param table_name: string name of the table. For special quoting,
use :class:`.quoted_name`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary representing the definition of
a primary key constraint.
.. seealso:: :meth:`Inspector.get_multi_pk_constraint`
"""
with self._operation_context() as conn:
return self.dialect.get_pk_constraint(
conn, table_name, schema, info_cache=self.info_cache, **kw
)
def get_multi_pk_constraint(
self,
schema: Optional[str] = None,
filter_names: Optional[Sequence[str]] = None,
kind: ObjectKind = ObjectKind.TABLE,
scope: ObjectScope = ObjectScope.DEFAULT,
**kw: Any,
) -> Dict[TableKey, ReflectedPrimaryKeyConstraint]:
r"""Return information about primary key constraints in
all tables in the given schema.
The tables can be filtered by passing the names to use to
``filter_names``.
For each table the value is a :class:`.ReflectedPrimaryKeyConstraint`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param filter_names: optionally return information only for the
objects listed here.
:param kind: a :class:`.ObjectKind` that specifies the type of objects
to reflect. Defaults to ``ObjectKind.TABLE``.
:param scope: a :class:`.ObjectScope` that specifies if primary keys of
default, temporary or any tables should be reflected.
Defaults to ``ObjectScope.DEFAULT``.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary where the keys are two-tuple schema,table-name
and the values are dictionaries, each representing the
definition of a primary key constraint.
The schema is ``None`` if no schema is provided.
.. versionadded:: 2.0
.. seealso:: :meth:`Inspector.get_pk_constraint`
"""
with self._operation_context() as conn:
return dict(
self.dialect.get_multi_pk_constraint(
conn,
schema=schema,
filter_names=filter_names,
kind=kind,
scope=scope,
info_cache=self.info_cache,
**kw,
)
)
def get_foreign_keys(
self, table_name: str, schema: Optional[str] = None, **kw: Any
) -> List[ReflectedForeignKeyConstraint]:
r"""Return information about foreign_keys in ``table_name``.
Given a string ``table_name``, and an optional string `schema`, return
foreign key information as a list of
:class:`.ReflectedForeignKeyConstraint`.
:param table_name: string name of the table. For special quoting,
use :class:`.quoted_name`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a list of dictionaries, each representing the
a foreign key definition.
.. seealso:: :meth:`Inspector.get_multi_foreign_keys`
"""
with self._operation_context() as conn:
return self.dialect.get_foreign_keys(
conn, table_name, schema, info_cache=self.info_cache, **kw
)
def get_multi_foreign_keys(
self,
schema: Optional[str] = None,
filter_names: Optional[Sequence[str]] = None,
kind: ObjectKind = ObjectKind.TABLE,
scope: ObjectScope = ObjectScope.DEFAULT,
**kw: Any,
) -> Dict[TableKey, List[ReflectedForeignKeyConstraint]]:
r"""Return information about foreign_keys in all tables
in the given schema.
The tables can be filtered by passing the names to use to
``filter_names``.
For each table the value is a list of
:class:`.ReflectedForeignKeyConstraint`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param filter_names: optionally return information only for the
objects listed here.
:param kind: a :class:`.ObjectKind` that specifies the type of objects
to reflect. Defaults to ``ObjectKind.TABLE``.
:param scope: a :class:`.ObjectScope` that specifies if foreign keys of
default, temporary or any tables should be reflected.
Defaults to ``ObjectScope.DEFAULT``.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary where the keys are two-tuple schema,table-name
and the values are list of dictionaries, each representing
a foreign key definition.
The schema is ``None`` if no schema is provided.
.. versionadded:: 2.0
.. seealso:: :meth:`Inspector.get_foreign_keys`
"""
with self._operation_context() as conn:
return dict(
self.dialect.get_multi_foreign_keys(
conn,
schema=schema,
filter_names=filter_names,
kind=kind,
scope=scope,
info_cache=self.info_cache,
**kw,
)
)
def get_indexes(
self, table_name: str, schema: Optional[str] = None, **kw: Any
) -> List[ReflectedIndex]:
r"""Return information about indexes in ``table_name``.
Given a string ``table_name`` and an optional string `schema`, return
index information as a list of :class:`.ReflectedIndex`.
:param table_name: string name of the table. For special quoting,
use :class:`.quoted_name`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a list of dictionaries, each representing the
definition of an index.
.. seealso:: :meth:`Inspector.get_multi_indexes`
"""
with self._operation_context() as conn:
return self.dialect.get_indexes(
conn, table_name, schema, info_cache=self.info_cache, **kw
)
def get_multi_indexes(
self,
schema: Optional[str] = None,
filter_names: Optional[Sequence[str]] = None,
kind: ObjectKind = ObjectKind.TABLE,
scope: ObjectScope = ObjectScope.DEFAULT,
**kw: Any,
) -> Dict[TableKey, List[ReflectedIndex]]:
r"""Return information about indexes in in all objects
in the given schema.
The objects can be filtered by passing the names to use to
``filter_names``.
For each table the value is a list of :class:`.ReflectedIndex`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param filter_names: optionally return information only for the
objects listed here.
:param kind: a :class:`.ObjectKind` that specifies the type of objects
to reflect. Defaults to ``ObjectKind.TABLE``.
:param scope: a :class:`.ObjectScope` that specifies if indexes of
default, temporary or any tables should be reflected.
Defaults to ``ObjectScope.DEFAULT``.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary where the keys are two-tuple schema,table-name
and the values are list of dictionaries, each representing the
definition of an index.
The schema is ``None`` if no schema is provided.
.. versionadded:: 2.0
.. seealso:: :meth:`Inspector.get_indexes`
"""
with self._operation_context() as conn:
return dict(
self.dialect.get_multi_indexes(
conn,
schema=schema,
filter_names=filter_names,
kind=kind,
scope=scope,
info_cache=self.info_cache,
**kw,
)
)
def get_unique_constraints(
self, table_name: str, schema: Optional[str] = None, **kw: Any
) -> List[ReflectedUniqueConstraint]:
r"""Return information about unique constraints in ``table_name``.
Given a string ``table_name`` and an optional string `schema`, return
unique constraint information as a list of
:class:`.ReflectedUniqueConstraint`.
:param table_name: string name of the table. For special quoting,
use :class:`.quoted_name`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a list of dictionaries, each representing the
definition of an unique constraint.
.. seealso:: :meth:`Inspector.get_multi_unique_constraints`
"""
with self._operation_context() as conn:
return self.dialect.get_unique_constraints(
conn, table_name, schema, info_cache=self.info_cache, **kw
)
def get_multi_unique_constraints(
self,
schema: Optional[str] = None,
filter_names: Optional[Sequence[str]] = None,
kind: ObjectKind = ObjectKind.TABLE,
scope: ObjectScope = ObjectScope.DEFAULT,
**kw: Any,
) -> Dict[TableKey, List[ReflectedUniqueConstraint]]:
r"""Return information about unique constraints in all tables
in the given schema.
The tables can be filtered by passing the names to use to
``filter_names``.
For each table the value is a list of
:class:`.ReflectedUniqueConstraint`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param filter_names: optionally return information only for the
objects listed here.
:param kind: a :class:`.ObjectKind` that specifies the type of objects
to reflect. Defaults to ``ObjectKind.TABLE``.
:param scope: a :class:`.ObjectScope` that specifies if constraints of
default, temporary or any tables should be reflected.
Defaults to ``ObjectScope.DEFAULT``.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary where the keys are two-tuple schema,table-name
and the values are list of dictionaries, each representing the
definition of an unique constraint.
The schema is ``None`` if no schema is provided.
.. versionadded:: 2.0
.. seealso:: :meth:`Inspector.get_unique_constraints`
"""
with self._operation_context() as conn:
return dict(
self.dialect.get_multi_unique_constraints(
conn,
schema=schema,
filter_names=filter_names,
kind=kind,
scope=scope,
info_cache=self.info_cache,
**kw,
)
)
def get_table_comment(
self, table_name: str, schema: Optional[str] = None, **kw: Any
) -> ReflectedTableComment:
r"""Return information about the table comment for ``table_name``.
Given a string ``table_name`` and an optional string ``schema``,
return table comment information as a :class:`.ReflectedTableComment`.
Raises ``NotImplementedError`` for a dialect that does not support
comments.
:param table_name: string name of the table. For special quoting,
use :class:`.quoted_name`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary, with the table comment.
.. versionadded:: 1.2
.. seealso:: :meth:`Inspector.get_multi_table_comment`
"""
with self._operation_context() as conn:
return self.dialect.get_table_comment(
conn, table_name, schema, info_cache=self.info_cache, **kw
)
def get_multi_table_comment(
self,
schema: Optional[str] = None,
filter_names: Optional[Sequence[str]] = None,
kind: ObjectKind = ObjectKind.TABLE,
scope: ObjectScope = ObjectScope.DEFAULT,
**kw: Any,
) -> Dict[TableKey, ReflectedTableComment]:
r"""Return information about the table comment in all objects
in the given schema.
The objects can be filtered by passing the names to use to
``filter_names``.
For each table the value is a :class:`.ReflectedTableComment`.
Raises ``NotImplementedError`` for a dialect that does not support
comments.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param filter_names: optionally return information only for the
objects listed here.
:param kind: a :class:`.ObjectKind` that specifies the type of objects
to reflect. Defaults to ``ObjectKind.TABLE``.
:param scope: a :class:`.ObjectScope` that specifies if comments of
default, temporary or any tables should be reflected.
Defaults to ``ObjectScope.DEFAULT``.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary where the keys are two-tuple schema,table-name
and the values are dictionaries, representing the
table comments.
The schema is ``None`` if no schema is provided.
.. versionadded:: 2.0
.. seealso:: :meth:`Inspector.get_table_comment`
"""
with self._operation_context() as conn:
return dict(
self.dialect.get_multi_table_comment(
conn,
schema=schema,
filter_names=filter_names,
kind=kind,
scope=scope,
info_cache=self.info_cache,
**kw,
)
)
def get_check_constraints(
self, table_name: str, schema: Optional[str] = None, **kw: Any
) -> List[ReflectedCheckConstraint]:
r"""Return information about check constraints in ``table_name``.
Given a string ``table_name`` and an optional string `schema`, return
check constraint information as a list of
:class:`.ReflectedCheckConstraint`.
:param table_name: string name of the table. For special quoting,
use :class:`.quoted_name`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a list of dictionaries, each representing the
definition of a check constraints.
.. seealso:: :meth:`Inspector.get_multi_check_constraints`
"""
with self._operation_context() as conn:
return self.dialect.get_check_constraints(
conn, table_name, schema, info_cache=self.info_cache, **kw
)
def get_multi_check_constraints(
self,
schema: Optional[str] = None,
filter_names: Optional[Sequence[str]] = None,
kind: ObjectKind = ObjectKind.TABLE,
scope: ObjectScope = ObjectScope.DEFAULT,
**kw: Any,
) -> Dict[TableKey, List[ReflectedCheckConstraint]]:
r"""Return information about check constraints in all tables
in the given schema.
The tables can be filtered by passing the names to use to
``filter_names``.
For each table the value is a list of
:class:`.ReflectedCheckConstraint`.
:param schema: string schema name; if omitted, uses the default schema
of the database connection. For special quoting,
use :class:`.quoted_name`.
:param filter_names: optionally return information only for the
objects listed here.
:param kind: a :class:`.ObjectKind` that specifies the type of objects
to reflect. Defaults to ``ObjectKind.TABLE``.
:param scope: a :class:`.ObjectScope` that specifies if constraints of
default, temporary or any tables should be reflected.
Defaults to ``ObjectScope.DEFAULT``.
:param \**kw: Additional keyword argument to pass to the dialect
specific implementation. See the documentation of the dialect
in use for more information.
:return: a dictionary where the keys are two-tuple schema,table-name
and the values are list of dictionaries, each representing the
definition of a check constraints.
The schema is ``None`` if no schema is provided.
.. versionadded:: 2.0
.. seealso:: :meth:`Inspector.get_check_constraints`
"""
with self._operation_context() as conn:
return dict(
self.dialect.get_multi_check_constraints(
conn,
schema=schema,
filter_names=filter_names,
kind=kind,
scope=scope,
info_cache=self.info_cache,
**kw,
)
)
def reflect_table(
self,
table: sa_schema.Table,
include_columns: Optional[Collection[str]],
exclude_columns: Collection[str] = (),
resolve_fks: bool = True,
_extend_on: Optional[Set[sa_schema.Table]] = None,
_reflect_info: Optional[_ReflectionInfo] = None,
) -> None:
"""Given a :class:`_schema.Table` object, load its internal
constructs based on introspection.
This is the underlying method used by most dialects to produce
table reflection. Direct usage is like::
from sqlalchemy import create_engine, MetaData, Table
from sqlalchemy import inspect
engine = create_engine('...')
meta = MetaData()
user_table = Table('user', meta)
insp = inspect(engine)
insp.reflect_table(user_table, None)
.. versionchanged:: 1.4 Renamed from ``reflecttable`` to
``reflect_table``
:param table: a :class:`~sqlalchemy.schema.Table` instance.
:param include_columns: a list of string column names to include
in the reflection process. If ``None``, all columns are reflected.
"""
if _extend_on is not None:
if table in _extend_on:
return
else:
_extend_on.add(table)
dialect = self.bind.dialect
with self._operation_context() as conn:
schema = conn.schema_for_object(table)
table_name = table.name
# get table-level arguments that are specifically
# intended for reflection, e.g. oracle_resolve_synonyms.
# these are unconditionally passed to related Table
# objects
reflection_options = {
k: table.dialect_kwargs.get(k)
for k in dialect.reflection_options
if k in table.dialect_kwargs
}
table_key = (schema, table_name)
if _reflect_info is None or table_key not in _reflect_info.columns:
_reflect_info = self._get_reflection_info(
schema,
filter_names=[table_name],
kind=ObjectKind.ANY,
scope=ObjectScope.ANY,
_reflect_info=_reflect_info,
**table.dialect_kwargs,
)
if table_key in _reflect_info.unreflectable:
raise _reflect_info.unreflectable[table_key]
if table_key not in _reflect_info.columns:
raise exc.NoSuchTableError(table_name)
# reflect table options, like mysql_engine
if _reflect_info.table_options:
tbl_opts = _reflect_info.table_options.get(table_key)
if tbl_opts:
# add additional kwargs to the Table if the dialect
# returned them
table._validate_dialect_kwargs(tbl_opts)
found_table = False
cols_by_orig_name: Dict[str, sa_schema.Column[Any]] = {}
for col_d in _reflect_info.columns[table_key]:
found_table = True
self._reflect_column(
table,
col_d,
include_columns,
exclude_columns,
cols_by_orig_name,
)
# NOTE: support tables/views with no columns
if not found_table and not self.has_table(table_name, schema):
raise exc.NoSuchTableError(table_name)
self._reflect_pk(
_reflect_info, table_key, table, cols_by_orig_name, exclude_columns
)
self._reflect_fk(
_reflect_info,
table_key,
table,
cols_by_orig_name,
include_columns,
exclude_columns,
resolve_fks,
_extend_on,
reflection_options,
)
self._reflect_indexes(
_reflect_info,
table_key,
table,
cols_by_orig_name,
include_columns,
exclude_columns,
reflection_options,
)
self._reflect_unique_constraints(
_reflect_info,
table_key,
table,
cols_by_orig_name,
include_columns,
exclude_columns,
reflection_options,
)
self._reflect_check_constraints(
_reflect_info,
table_key,
table,
cols_by_orig_name,
include_columns,
exclude_columns,
reflection_options,
)
self._reflect_table_comment(
_reflect_info,
table_key,
table,
reflection_options,
)
def _reflect_column(
self,
table: sa_schema.Table,
col_d: ReflectedColumn,
include_columns: Optional[Collection[str]],
exclude_columns: Collection[str],
cols_by_orig_name: Dict[str, sa_schema.Column[Any]],
) -> None:
orig_name = col_d["name"]
table.metadata.dispatch.column_reflect(self, table, col_d)
table.dispatch.column_reflect(self, table, col_d)
# fetch name again as column_reflect is allowed to
# change it
name = col_d["name"]
if (include_columns and name not in include_columns) or (
exclude_columns and name in exclude_columns
):
return
coltype = col_d["type"]
col_kw = {
k: col_d[k] # type: ignore[literal-required]
for k in [
"nullable",
"autoincrement",
"quote",
"info",
"key",
"comment",
]
if k in col_d
}
if "dialect_options" in col_d:
col_kw.update(col_d["dialect_options"])
colargs = []
default: Any
if col_d.get("default") is not None:
default_text = col_d["default"]
assert default_text is not None
if isinstance(default_text, TextClause):
default = sa_schema.DefaultClause(
default_text, _reflected=True
)
elif not isinstance(default_text, sa_schema.FetchedValue):
default = sa_schema.DefaultClause(
sql.text(default_text), _reflected=True
)
else:
default = default_text
colargs.append(default)
if "computed" in col_d:
computed = sa_schema.Computed(**col_d["computed"])
colargs.append(computed)
if "identity" in col_d:
identity = sa_schema.Identity(**col_d["identity"])
colargs.append(identity)
cols_by_orig_name[orig_name] = col = sa_schema.Column(
name, coltype, *colargs, **col_kw
)
if col.key in table.primary_key:
col.primary_key = True
table.append_column(col, replace_existing=True)
def _reflect_pk(
self,
_reflect_info: _ReflectionInfo,
table_key: TableKey,
table: sa_schema.Table,
cols_by_orig_name: Dict[str, sa_schema.Column[Any]],
exclude_columns: Collection[str],
) -> None:
pk_cons = _reflect_info.pk_constraint.get(table_key)
if pk_cons:
pk_cols = [
cols_by_orig_name[pk]
for pk in pk_cons["constrained_columns"]
if pk in cols_by_orig_name and pk not in exclude_columns
]
# update pk constraint name and comment
table.primary_key.name = pk_cons.get("name")
table.primary_key.comment = pk_cons.get("comment", None)
# tell the PKConstraint to re-initialize
# its column collection
table.primary_key._reload(pk_cols)
def _reflect_fk(
self,
_reflect_info: _ReflectionInfo,
table_key: TableKey,
table: sa_schema.Table,
cols_by_orig_name: Dict[str, sa_schema.Column[Any]],
include_columns: Optional[Collection[str]],
exclude_columns: Collection[str],
resolve_fks: bool,
_extend_on: Optional[Set[sa_schema.Table]],
reflection_options: Dict[str, Any],
) -> None:
fkeys = _reflect_info.foreign_keys.get(table_key, [])
for fkey_d in fkeys:
conname = fkey_d["name"]
# look for columns by orig name in cols_by_orig_name,
# but support columns that are in-Python only as fallback
constrained_columns = [
cols_by_orig_name[c].key if c in cols_by_orig_name else c
for c in fkey_d["constrained_columns"]
]
if (
exclude_columns
and set(constrained_columns).intersection(exclude_columns)
or (
include_columns
and set(constrained_columns).difference(include_columns)
)
):
continue
referred_schema = fkey_d["referred_schema"]
referred_table = fkey_d["referred_table"]
referred_columns = fkey_d["referred_columns"]
refspec = []
if referred_schema is not None:
if resolve_fks:
sa_schema.Table(
referred_table,
table.metadata,
schema=referred_schema,
autoload_with=self.bind,
_extend_on=_extend_on,
_reflect_info=_reflect_info,
**reflection_options,
)
for column in referred_columns:
refspec.append(
".".join([referred_schema, referred_table, column])
)
else:
if resolve_fks:
sa_schema.Table(
referred_table,
table.metadata,
autoload_with=self.bind,
schema=sa_schema.BLANK_SCHEMA,
_extend_on=_extend_on,
_reflect_info=_reflect_info,
**reflection_options,
)
for column in referred_columns:
refspec.append(".".join([referred_table, column]))
if "options" in fkey_d:
options = fkey_d["options"]
else:
options = {}
try:
table.append_constraint(
sa_schema.ForeignKeyConstraint(
constrained_columns,
refspec,
conname,
link_to_name=True,
comment=fkey_d.get("comment"),
**options,
)
)
except exc.ConstraintColumnNotFoundError:
util.warn(
f"On reflected table {table.name}, skipping reflection of "
"foreign key constraint "
f"{conname}; one or more subject columns within "
f"name(s) {', '.join(constrained_columns)} are not "
"present in the table"
)
_index_sort_exprs = {
"asc": operators.asc_op,
"desc": operators.desc_op,
"nulls_first": operators.nulls_first_op,
"nulls_last": operators.nulls_last_op,
}
def _reflect_indexes(
self,
_reflect_info: _ReflectionInfo,
table_key: TableKey,
table: sa_schema.Table,
cols_by_orig_name: Dict[str, sa_schema.Column[Any]],
include_columns: Optional[Collection[str]],
exclude_columns: Collection[str],
reflection_options: Dict[str, Any],
) -> None:
# Indexes
indexes = _reflect_info.indexes.get(table_key, [])
for index_d in indexes:
name = index_d["name"]
columns = index_d["column_names"]
expressions = index_d.get("expressions")
column_sorting = index_d.get("column_sorting", {})
unique = index_d["unique"]
flavor = index_d.get("type", "index")
dialect_options = index_d.get("dialect_options", {})
duplicates = index_d.get("duplicates_constraint")
if include_columns and not set(columns).issubset(include_columns):
continue
if duplicates:
continue
# look for columns by orig name in cols_by_orig_name,
# but support columns that are in-Python only as fallback
idx_element: Any
idx_elements = []
for index, c in enumerate(columns):
if c is None:
if not expressions:
util.warn(
f"Skipping {flavor} {name!r} because key "
f"{index + 1} reflected as None but no "
"'expressions' were returned"
)
break
idx_element = sql.text(expressions[index])
else:
try:
if c in cols_by_orig_name:
idx_element = cols_by_orig_name[c]
else:
idx_element = table.c[c]
except KeyError:
util.warn(
f"{flavor} key {c!r} was not located in "
f"columns for table {table.name!r}"
)
continue
for option in column_sorting.get(c, ()):
if option in self._index_sort_exprs:
op = self._index_sort_exprs[option]
idx_element = op(idx_element)
idx_elements.append(idx_element)
else:
sa_schema.Index(
name,
*idx_elements,
_table=table,
unique=unique,
**dialect_options,
)
def _reflect_unique_constraints(
self,
_reflect_info: _ReflectionInfo,
table_key: TableKey,
table: sa_schema.Table,
cols_by_orig_name: Dict[str, sa_schema.Column[Any]],
include_columns: Optional[Collection[str]],
exclude_columns: Collection[str],
reflection_options: Dict[str, Any],
) -> None:
constraints = _reflect_info.unique_constraints.get(table_key, [])
# Unique Constraints
for const_d in constraints:
conname = const_d["name"]
columns = const_d["column_names"]
comment = const_d.get("comment")
duplicates = const_d.get("duplicates_index")
dialect_options = const_d.get("dialect_options", {})
if include_columns and not set(columns).issubset(include_columns):
continue
if duplicates:
continue
# look for columns by orig name in cols_by_orig_name,
# but support columns that are in-Python only as fallback
constrained_cols = []
for c in columns:
try:
constrained_col = (
cols_by_orig_name[c]
if c in cols_by_orig_name
else table.c[c]
)
except KeyError:
util.warn(
"unique constraint key '%s' was not located in "
"columns for table '%s'" % (c, table.name)
)
else:
constrained_cols.append(constrained_col)
table.append_constraint(
sa_schema.UniqueConstraint(
*constrained_cols,
name=conname,
comment=comment,
**dialect_options,
)
)
def _reflect_check_constraints(
self,
_reflect_info: _ReflectionInfo,
table_key: TableKey,
table: sa_schema.Table,
cols_by_orig_name: Dict[str, sa_schema.Column[Any]],
include_columns: Optional[Collection[str]],
exclude_columns: Collection[str],
reflection_options: Dict[str, Any],
) -> None:
constraints = _reflect_info.check_constraints.get(table_key, [])
for const_d in constraints:
table.append_constraint(sa_schema.CheckConstraint(**const_d))
def _reflect_table_comment(
self,
_reflect_info: _ReflectionInfo,
table_key: TableKey,
table: sa_schema.Table,
reflection_options: Dict[str, Any],
) -> None:
comment_dict = _reflect_info.table_comment.get(table_key)
if comment_dict:
table.comment = comment_dict["text"]
def _get_reflection_info(
self,
schema: Optional[str] = None,
filter_names: Optional[Collection[str]] = None,
available: Optional[Collection[str]] = None,
_reflect_info: Optional[_ReflectionInfo] = None,
**kw: Any,
) -> _ReflectionInfo:
kw["schema"] = schema
if filter_names and available and len(filter_names) > 100:
fraction = len(filter_names) / len(available)
else:
fraction = None
unreflectable: Dict[TableKey, exc.UnreflectableTableError]
kw["unreflectable"] = unreflectable = {}
has_result: bool = True
def run(
meth: Any,
*,
optional: bool = False,
check_filter_names_from_meth: bool = False,
) -> Any:
nonlocal has_result
# simple heuristic to improve reflection performance if a
# dialect implements multi_reflection:
# if more than 50% of the tables in the db are in filter_names
# load all the tables, since it's most likely faster to avoid
# a filter on that many tables.
if (
fraction is None
or fraction <= 0.5
or not self.dialect._overrides_default(meth.__name__)
):
_fn = filter_names
else:
_fn = None
try:
if has_result:
res = meth(filter_names=_fn, **kw)
if check_filter_names_from_meth and not res:
# method returned no result data.
# skip any future call methods
has_result = False
else:
res = {}
except NotImplementedError:
if not optional:
raise
res = {}
return res
info = _ReflectionInfo(
columns=run(
self.get_multi_columns, check_filter_names_from_meth=True
),
pk_constraint=run(self.get_multi_pk_constraint),
foreign_keys=run(self.get_multi_foreign_keys),
indexes=run(self.get_multi_indexes),
unique_constraints=run(
self.get_multi_unique_constraints, optional=True
),
table_comment=run(self.get_multi_table_comment, optional=True),
check_constraints=run(
self.get_multi_check_constraints, optional=True
),
table_options=run(self.get_multi_table_options, optional=True),
unreflectable=unreflectable,
)
if _reflect_info:
_reflect_info.update(info)
return _reflect_info
else:
return info
@final
class ReflectionDefaults:
"""provides blank default values for reflection methods."""
@classmethod
def columns(cls) -> List[ReflectedColumn]:
return []
@classmethod
def pk_constraint(cls) -> ReflectedPrimaryKeyConstraint:
return {
"name": None,
"constrained_columns": [],
}
@classmethod
def foreign_keys(cls) -> List[ReflectedForeignKeyConstraint]:
return []
@classmethod
def indexes(cls) -> List[ReflectedIndex]:
return []
@classmethod
def unique_constraints(cls) -> List[ReflectedUniqueConstraint]:
return []
@classmethod
def check_constraints(cls) -> List[ReflectedCheckConstraint]:
return []
@classmethod
def table_options(cls) -> Dict[str, Any]:
return {}
@classmethod
def table_comment(cls) -> ReflectedTableComment:
return {"text": None}
@dataclass
class _ReflectionInfo:
columns: Dict[TableKey, List[ReflectedColumn]]
pk_constraint: Dict[TableKey, Optional[ReflectedPrimaryKeyConstraint]]
foreign_keys: Dict[TableKey, List[ReflectedForeignKeyConstraint]]
indexes: Dict[TableKey, List[ReflectedIndex]]
# optionals
unique_constraints: Dict[TableKey, List[ReflectedUniqueConstraint]]
table_comment: Dict[TableKey, Optional[ReflectedTableComment]]
check_constraints: Dict[TableKey, List[ReflectedCheckConstraint]]
table_options: Dict[TableKey, Dict[str, Any]]
unreflectable: Dict[TableKey, exc.UnreflectableTableError]
def update(self, other: _ReflectionInfo) -> None:
for k, v in self.__dict__.items():
ov = getattr(other, k)
if ov is not None:
if v is None:
setattr(self, k, ov)
else:
v.update(ov)