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# ### this file stubs are generated by tools/write_pyi.py - do not edit ###
# ### imports are manually managed
from __future__ import annotations
from contextlib import contextmanager
from typing import Any
from typing import Awaitable
from typing import Callable
from typing import Dict
from typing import Iterator
from typing import List
from typing import Literal
from typing import Mapping
from typing import Optional
from typing import Sequence
from typing import Tuple
from typing import Type
from typing import TYPE_CHECKING
from typing import TypeVar
from typing import Union
from sqlalchemy.sql.expression import TableClause
from sqlalchemy.sql.expression import Update
if TYPE_CHECKING:
from sqlalchemy.engine import Connection
from sqlalchemy.sql.elements import BinaryExpression
from sqlalchemy.sql.elements import conv
from sqlalchemy.sql.elements import TextClause
from sqlalchemy.sql.functions import Function
from sqlalchemy.sql.schema import Column
from sqlalchemy.sql.schema import Computed
from sqlalchemy.sql.schema import Identity
from sqlalchemy.sql.schema import SchemaItem
from sqlalchemy.sql.schema import Table
from sqlalchemy.sql.type_api import TypeEngine
from sqlalchemy.util import immutabledict
from .operations.ops import BatchOperations
from .operations.ops import MigrateOperation
from .runtime.migration import MigrationContext
from .util.sqla_compat import _literal_bindparam
_T = TypeVar("_T")
### end imports ###
def add_column(
table_name: str, column: Column[Any], *, schema: Optional[str] = None
) -> None:
"""Issue an "add column" instruction using the current
migration context.
e.g.::
from alembic import op
from sqlalchemy import Column, String
op.add_column("organization", Column("name", String()))
The :meth:`.Operations.add_column` method typically corresponds
to the SQL command "ALTER TABLE... ADD COLUMN". Within the scope
of this command, the column's name, datatype, nullability,
and optional server-generated defaults may be indicated.
.. note::
With the exception of NOT NULL constraints or single-column FOREIGN
KEY constraints, other kinds of constraints such as PRIMARY KEY,
UNIQUE or CHECK constraints **cannot** be generated using this
method; for these constraints, refer to operations such as
:meth:`.Operations.create_primary_key` and
:meth:`.Operations.create_check_constraint`. In particular, the
following :class:`~sqlalchemy.schema.Column` parameters are
**ignored**:
* :paramref:`~sqlalchemy.schema.Column.primary_key` - SQL databases
typically do not support an ALTER operation that can add
individual columns one at a time to an existing primary key
constraint, therefore it's less ambiguous to use the
:meth:`.Operations.create_primary_key` method, which assumes no
existing primary key constraint is present.
* :paramref:`~sqlalchemy.schema.Column.unique` - use the
:meth:`.Operations.create_unique_constraint` method
* :paramref:`~sqlalchemy.schema.Column.index` - use the
:meth:`.Operations.create_index` method
The provided :class:`~sqlalchemy.schema.Column` object may include a
:class:`~sqlalchemy.schema.ForeignKey` constraint directive,
referencing a remote table name. For this specific type of constraint,
Alembic will automatically emit a second ALTER statement in order to
add the single-column FOREIGN KEY constraint separately::
from alembic import op
from sqlalchemy import Column, INTEGER, ForeignKey
op.add_column(
"organization",
Column("account_id", INTEGER, ForeignKey("accounts.id")),
)
The column argument passed to :meth:`.Operations.add_column` is a
:class:`~sqlalchemy.schema.Column` construct, used in the same way it's
used in SQLAlchemy. In particular, values or functions to be indicated
as producing the column's default value on the database side are
specified using the ``server_default`` parameter, and not ``default``
which only specifies Python-side defaults::
from alembic import op
from sqlalchemy import Column, TIMESTAMP, func
# specify "DEFAULT NOW" along with the column add
op.add_column(
"account",
Column("timestamp", TIMESTAMP, server_default=func.now()),
)
:param table_name: String name of the parent table.
:param column: a :class:`sqlalchemy.schema.Column` object
representing the new column.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
"""
def alter_column(
table_name: str,
column_name: str,
*,
nullable: Optional[bool] = None,
comment: Union[str, Literal[False], None] = False,
server_default: Any = False,
new_column_name: Optional[str] = None,
type_: Union[TypeEngine, Type[TypeEngine], None] = None,
existing_type: Union[TypeEngine, Type[TypeEngine], None] = None,
existing_server_default: Union[
str, bool, Identity, Computed, None
] = False,
existing_nullable: Optional[bool] = None,
existing_comment: Optional[str] = None,
schema: Optional[str] = None,
**kw: Any,
) -> None:
r"""Issue an "alter column" instruction using the
current migration context.
Generally, only that aspect of the column which
is being changed, i.e. name, type, nullability,
default, needs to be specified. Multiple changes
can also be specified at once and the backend should
"do the right thing", emitting each change either
separately or together as the backend allows.
MySQL has special requirements here, since MySQL
cannot ALTER a column without a full specification.
When producing MySQL-compatible migration files,
it is recommended that the ``existing_type``,
``existing_server_default``, and ``existing_nullable``
parameters be present, if not being altered.
Type changes which are against the SQLAlchemy
"schema" types :class:`~sqlalchemy.types.Boolean`
and :class:`~sqlalchemy.types.Enum` may also
add or drop constraints which accompany those
types on backends that don't support them natively.
The ``existing_type`` argument is
used in this case to identify and remove a previous
constraint that was bound to the type object.
:param table_name: string name of the target table.
:param column_name: string name of the target column,
as it exists before the operation begins.
:param nullable: Optional; specify ``True`` or ``False``
to alter the column's nullability.
:param server_default: Optional; specify a string
SQL expression, :func:`~sqlalchemy.sql.expression.text`,
or :class:`~sqlalchemy.schema.DefaultClause` to indicate
an alteration to the column's default value.
Set to ``None`` to have the default removed.
:param comment: optional string text of a new comment to add to the
column.
.. versionadded:: 1.0.6
:param new_column_name: Optional; specify a string name here to
indicate the new name within a column rename operation.
:param type\_: Optional; a :class:`~sqlalchemy.types.TypeEngine`
type object to specify a change to the column's type.
For SQLAlchemy types that also indicate a constraint (i.e.
:class:`~sqlalchemy.types.Boolean`, :class:`~sqlalchemy.types.Enum`),
the constraint is also generated.
:param autoincrement: set the ``AUTO_INCREMENT`` flag of the column;
currently understood by the MySQL dialect.
:param existing_type: Optional; a
:class:`~sqlalchemy.types.TypeEngine`
type object to specify the previous type. This
is required for all MySQL column alter operations that
don't otherwise specify a new type, as well as for
when nullability is being changed on a SQL Server
column. It is also used if the type is a so-called
SQLlchemy "schema" type which may define a constraint (i.e.
:class:`~sqlalchemy.types.Boolean`,
:class:`~sqlalchemy.types.Enum`),
so that the constraint can be dropped.
:param existing_server_default: Optional; The existing
default value of the column. Required on MySQL if
an existing default is not being changed; else MySQL
removes the default.
:param existing_nullable: Optional; the existing nullability
of the column. Required on MySQL if the existing nullability
is not being changed; else MySQL sets this to NULL.
:param existing_autoincrement: Optional; the existing autoincrement
of the column. Used for MySQL's system of altering a column
that specifies ``AUTO_INCREMENT``.
:param existing_comment: string text of the existing comment on the
column to be maintained. Required on MySQL if the existing comment
on the column is not being changed.
.. versionadded:: 1.0.6
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
:param postgresql_using: String argument which will indicate a
SQL expression to render within the Postgresql-specific USING clause
within ALTER COLUMN. This string is taken directly as raw SQL which
must explicitly include any necessary quoting or escaping of tokens
within the expression.
"""
@contextmanager
def batch_alter_table(
table_name: str,
schema: Optional[str] = None,
recreate: Literal["auto", "always", "never"] = "auto",
partial_reordering: Optional[tuple] = None,
copy_from: Optional[Table] = None,
table_args: Tuple[Any, ...] = (),
table_kwargs: Mapping[str, Any] = immutabledict({}),
reflect_args: Tuple[Any, ...] = (),
reflect_kwargs: Mapping[str, Any] = immutabledict({}),
naming_convention: Optional[Dict[str, str]] = None,
) -> Iterator[BatchOperations]:
"""Invoke a series of per-table migrations in batch.
Batch mode allows a series of operations specific to a table
to be syntactically grouped together, and allows for alternate
modes of table migration, in particular the "recreate" style of
migration required by SQLite.
"recreate" style is as follows:
1. A new table is created with the new specification, based on the
migration directives within the batch, using a temporary name.
2. the data copied from the existing table to the new table.
3. the existing table is dropped.
4. the new table is renamed to the existing table name.
The directive by default will only use "recreate" style on the
SQLite backend, and only if directives are present which require
this form, e.g. anything other than ``add_column()``. The batch
operation on other backends will proceed using standard ALTER TABLE
operations.
The method is used as a context manager, which returns an instance
of :class:`.BatchOperations`; this object is the same as
:class:`.Operations` except that table names and schema names
are omitted. E.g.::
with op.batch_alter_table("some_table") as batch_op:
batch_op.add_column(Column("foo", Integer))
batch_op.drop_column("bar")
The operations within the context manager are invoked at once
when the context is ended. When run against SQLite, if the
migrations include operations not supported by SQLite's ALTER TABLE,
the entire table will be copied to a new one with the new
specification, moving all data across as well.
The copy operation by default uses reflection to retrieve the current
structure of the table, and therefore :meth:`.batch_alter_table`
in this mode requires that the migration is run in "online" mode.
The ``copy_from`` parameter may be passed which refers to an existing
:class:`.Table` object, which will bypass this reflection step.
.. note:: The table copy operation will currently not copy
CHECK constraints, and may not copy UNIQUE constraints that are
unnamed, as is possible on SQLite. See the section
:ref:`sqlite_batch_constraints` for workarounds.
:param table_name: name of table
:param schema: optional schema name.
:param recreate: under what circumstances the table should be
recreated. At its default of ``"auto"``, the SQLite dialect will
recreate the table if any operations other than ``add_column()``,
``create_index()``, or ``drop_index()`` are
present. Other options include ``"always"`` and ``"never"``.
:param copy_from: optional :class:`~sqlalchemy.schema.Table` object
that will act as the structure of the table being copied. If omitted,
table reflection is used to retrieve the structure of the table.
.. seealso::
:ref:`batch_offline_mode`
:paramref:`~.Operations.batch_alter_table.reflect_args`
:paramref:`~.Operations.batch_alter_table.reflect_kwargs`
:param reflect_args: a sequence of additional positional arguments that
will be applied to the table structure being reflected / copied;
this may be used to pass column and constraint overrides to the
table that will be reflected, in lieu of passing the whole
:class:`~sqlalchemy.schema.Table` using
:paramref:`~.Operations.batch_alter_table.copy_from`.
:param reflect_kwargs: a dictionary of additional keyword arguments
that will be applied to the table structure being copied; this may be
used to pass additional table and reflection options to the table that
will be reflected, in lieu of passing the whole
:class:`~sqlalchemy.schema.Table` using
:paramref:`~.Operations.batch_alter_table.copy_from`.
:param table_args: a sequence of additional positional arguments that
will be applied to the new :class:`~sqlalchemy.schema.Table` when
created, in addition to those copied from the source table.
This may be used to provide additional constraints such as CHECK
constraints that may not be reflected.
:param table_kwargs: a dictionary of additional keyword arguments
that will be applied to the new :class:`~sqlalchemy.schema.Table`
when created, in addition to those copied from the source table.
This may be used to provide for additional table options that may
not be reflected.
:param naming_convention: a naming convention dictionary of the form
described at :ref:`autogen_naming_conventions` which will be applied
to the :class:`~sqlalchemy.schema.MetaData` during the reflection
process. This is typically required if one wants to drop SQLite
constraints, as these constraints will not have names when
reflected on this backend. Requires SQLAlchemy **0.9.4** or greater.
.. seealso::
:ref:`dropping_sqlite_foreign_keys`
:param partial_reordering: a list of tuples, each suggesting a desired
ordering of two or more columns in the newly created table. Requires
that :paramref:`.batch_alter_table.recreate` is set to ``"always"``.
Examples, given a table with columns "a", "b", "c", and "d":
Specify the order of all columns::
with op.batch_alter_table(
"some_table",
recreate="always",
partial_reordering=[("c", "d", "a", "b")],
) as batch_op:
pass
Ensure "d" appears before "c", and "b", appears before "a"::
with op.batch_alter_table(
"some_table",
recreate="always",
partial_reordering=[("d", "c"), ("b", "a")],
) as batch_op:
pass
The ordering of columns not included in the partial_reordering
set is undefined. Therefore it is best to specify the complete
ordering of all columns for best results.
.. versionadded:: 1.4.0
.. note:: batch mode requires SQLAlchemy 0.8 or above.
.. seealso::
:ref:`batch_migrations`
"""
def bulk_insert(
table: Union[Table, TableClause],
rows: List[dict],
*,
multiinsert: bool = True,
) -> None:
"""Issue a "bulk insert" operation using the current
migration context.
This provides a means of representing an INSERT of multiple rows
which works equally well in the context of executing on a live
connection as well as that of generating a SQL script. In the
case of a SQL script, the values are rendered inline into the
statement.
e.g.::
from alembic import op
from datetime import date
from sqlalchemy.sql import table, column
from sqlalchemy import String, Integer, Date
# Create an ad-hoc table to use for the insert statement.
accounts_table = table(
"account",
column("id", Integer),
column("name", String),
column("create_date", Date),
)
op.bulk_insert(
accounts_table,
[
{
"id": 1,
"name": "John Smith",
"create_date": date(2010, 10, 5),
},
{
"id": 2,
"name": "Ed Williams",
"create_date": date(2007, 5, 27),
},
{
"id": 3,
"name": "Wendy Jones",
"create_date": date(2008, 8, 15),
},
],
)
When using --sql mode, some datatypes may not render inline
automatically, such as dates and other special types. When this
issue is present, :meth:`.Operations.inline_literal` may be used::
op.bulk_insert(
accounts_table,
[
{
"id": 1,
"name": "John Smith",
"create_date": op.inline_literal("2010-10-05"),
},
{
"id": 2,
"name": "Ed Williams",
"create_date": op.inline_literal("2007-05-27"),
},
{
"id": 3,
"name": "Wendy Jones",
"create_date": op.inline_literal("2008-08-15"),
},
],
multiinsert=False,
)
When using :meth:`.Operations.inline_literal` in conjunction with
:meth:`.Operations.bulk_insert`, in order for the statement to work
in "online" (e.g. non --sql) mode, the
:paramref:`~.Operations.bulk_insert.multiinsert`
flag should be set to ``False``, which will have the effect of
individual INSERT statements being emitted to the database, each
with a distinct VALUES clause, so that the "inline" values can
still be rendered, rather than attempting to pass the values
as bound parameters.
:param table: a table object which represents the target of the INSERT.
:param rows: a list of dictionaries indicating rows.
:param multiinsert: when at its default of True and --sql mode is not
enabled, the INSERT statement will be executed using
"executemany()" style, where all elements in the list of
dictionaries are passed as bound parameters in a single
list. Setting this to False results in individual INSERT
statements being emitted per parameter set, and is needed
in those cases where non-literal values are present in the
parameter sets.
"""
def create_check_constraint(
constraint_name: Optional[str],
table_name: str,
condition: Union[str, BinaryExpression, TextClause],
*,
schema: Optional[str] = None,
**kw: Any,
) -> None:
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column("name")) > 5,
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
"""
def create_exclude_constraint(
constraint_name: str, table_name: str, *elements: Any, **kw: Any
) -> Optional[Table]:
"""Issue an alter to create an EXCLUDE constraint using the
current migration context.
.. note:: This method is Postgresql specific, and additionally
requires at least SQLAlchemy 1.0.
e.g.::
from alembic import op
op.create_exclude_constraint(
"user_excl",
"user",
("period", "&&"),
("group", "="),
where=("group != 'some group'"),
)
Note that the expressions work the same way as that of
the ``ExcludeConstraint`` object itself; if plain strings are
passed, quoting rules must be applied manually.
:param name: Name of the constraint.
:param table_name: String name of the source table.
:param elements: exclude conditions.
:param where: SQL expression or SQL string with optional WHERE
clause.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within.
"""
def create_foreign_key(
constraint_name: Optional[str],
source_table: str,
referent_table: str,
local_cols: List[str],
remote_cols: List[str],
*,
onupdate: Optional[str] = None,
ondelete: Optional[str] = None,
deferrable: Optional[bool] = None,
initially: Optional[str] = None,
match: Optional[str] = None,
source_schema: Optional[str] = None,
referent_schema: Optional[str] = None,
**dialect_kw: Any,
) -> None:
"""Issue a "create foreign key" instruction using the
current migration context.
e.g.::
from alembic import op
op.create_foreign_key(
"fk_user_address",
"address",
"user",
["user_id"],
["id"],
)
This internally generates a :class:`~sqlalchemy.schema.Table` object
containing the necessary columns, then generates a new
:class:`~sqlalchemy.schema.ForeignKeyConstraint`
object which it then associates with the
:class:`~sqlalchemy.schema.Table`.
Any event listeners associated with this action will be fired
off normally. The :class:`~sqlalchemy.schema.AddConstraint`
construct is ultimately used to generate the ALTER statement.
:param constraint_name: Name of the foreign key constraint. The name
is necessary so that an ALTER statement can be emitted. For setups
that use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param source_table: String name of the source table.
:param referent_table: String name of the destination table.
:param local_cols: a list of string column names in the
source table.
:param remote_cols: a list of string column names in the
remote table.
:param onupdate: Optional string. If set, emit ON UPDATE <value> when
issuing DDL for this constraint. Typical values include CASCADE,
DELETE and RESTRICT.
:param ondelete: Optional string. If set, emit ON DELETE <value> when
issuing DDL for this constraint. Typical values include CASCADE,
DELETE and RESTRICT.
:param deferrable: optional bool. If set, emit DEFERRABLE or NOT
DEFERRABLE when issuing DDL for this constraint.
:param source_schema: Optional schema name of the source table.
:param referent_schema: Optional schema name of the destination table.
"""
def create_index(
index_name: Optional[str],
table_name: str,
columns: Sequence[Union[str, TextClause, Function[Any]]],
*,
schema: Optional[str] = None,
unique: bool = False,
**kw: Any,
) -> None:
r"""Issue a "create index" instruction using the current
migration context.
e.g.::
from alembic import op
op.create_index("ik_test", "t1", ["foo", "bar"])
Functional indexes can be produced by using the
:func:`sqlalchemy.sql.expression.text` construct::
from alembic import op
from sqlalchemy import text
op.create_index("ik_test", "t1", [text("lower(foo)")])
:param index_name: name of the index.
:param table_name: name of the owning table.
:param columns: a list consisting of string column names and/or
:func:`~sqlalchemy.sql.expression.text` constructs.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
:param unique: If True, create a unique index.
:param quote:
Force quoting of this column's name on or off, corresponding
to ``True`` or ``False``. When left at its default
of ``None``, the column identifier will be quoted according to
whether the name is case sensitive (identifiers with at least one
upper case character are treated as case sensitive), or if it's a
reserved word. This flag is only needed to force quoting of a
reserved word which is not known by the SQLAlchemy dialect.
:param \**kw: Additional keyword arguments not mentioned above are
dialect specific, and passed in the form
``<dialectname>_<argname>``.
See the documentation regarding an individual dialect at
:ref:`dialect_toplevel` for detail on documented arguments.
"""
def create_primary_key(
constraint_name: Optional[str],
table_name: str,
columns: List[str],
*,
schema: Optional[str] = None,
) -> None:
"""Issue a "create primary key" instruction using the current
migration context.
e.g.::
from alembic import op
op.create_primary_key("pk_my_table", "my_table", ["id", "version"])
This internally generates a :class:`~sqlalchemy.schema.Table` object
containing the necessary columns, then generates a new
:class:`~sqlalchemy.schema.PrimaryKeyConstraint`
object which it then associates with the
:class:`~sqlalchemy.schema.Table`.
Any event listeners associated with this action will be fired
off normally. The :class:`~sqlalchemy.schema.AddConstraint`
construct is ultimately used to generate the ALTER statement.
:param constraint_name: Name of the primary key constraint. The name
is necessary so that an ALTER statement can be emitted. For setups
that use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the target table.
:param columns: a list of string column names to be applied to the
primary key constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
"""
def create_table(table_name: str, *columns: SchemaItem, **kw: Any) -> Table:
r"""Issue a "create table" instruction using the current migration
context.
This directive receives an argument list similar to that of the
traditional :class:`sqlalchemy.schema.Table` construct, but without the
metadata::
from sqlalchemy import INTEGER, VARCHAR, NVARCHAR, Column
from alembic import op
op.create_table(
"account",
Column("id", INTEGER, primary_key=True),
Column("name", VARCHAR(50), nullable=False),
Column("description", NVARCHAR(200)),
Column("timestamp", TIMESTAMP, server_default=func.now()),
)
Note that :meth:`.create_table` accepts
:class:`~sqlalchemy.schema.Column`
constructs directly from the SQLAlchemy library. In particular,
default values to be created on the database side are
specified using the ``server_default`` parameter, and not
``default`` which only specifies Python-side defaults::
from alembic import op
from sqlalchemy import Column, TIMESTAMP, func
# specify "DEFAULT NOW" along with the "timestamp" column
op.create_table(
"account",
Column("id", INTEGER, primary_key=True),
Column("timestamp", TIMESTAMP, server_default=func.now()),
)
The function also returns a newly created
:class:`~sqlalchemy.schema.Table` object, corresponding to the table
specification given, which is suitable for
immediate SQL operations, in particular
:meth:`.Operations.bulk_insert`::
from sqlalchemy import INTEGER, VARCHAR, NVARCHAR, Column
from alembic import op
account_table = op.create_table(
"account",
Column("id", INTEGER, primary_key=True),
Column("name", VARCHAR(50), nullable=False),
Column("description", NVARCHAR(200)),
Column("timestamp", TIMESTAMP, server_default=func.now()),
)
op.bulk_insert(
account_table,
[
{"name": "A1", "description": "account 1"},
{"name": "A2", "description": "account 2"},
],
)
:param table_name: Name of the table
:param \*columns: collection of :class:`~sqlalchemy.schema.Column`
objects within
the table, as well as optional :class:`~sqlalchemy.schema.Constraint`
objects
and :class:`~.sqlalchemy.schema.Index` objects.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
:param \**kw: Other keyword arguments are passed to the underlying
:class:`sqlalchemy.schema.Table` object created for the command.
:return: the :class:`~sqlalchemy.schema.Table` object corresponding
to the parameters given.
"""
def create_table_comment(
table_name: str,
comment: Optional[str],
*,
existing_comment: Optional[str] = None,
schema: Optional[str] = None,
) -> None:
"""Emit a COMMENT ON operation to set the comment for a table.
.. versionadded:: 1.0.6
:param table_name: string name of the target table.
:param comment: string value of the comment being registered against
the specified table.
:param existing_comment: String value of a comment
already registered on the specified table, used within autogenerate
so that the operation is reversible, but not required for direct
use.
.. seealso::
:meth:`.Operations.drop_table_comment`
:paramref:`.Operations.alter_column.comment`
"""
def create_unique_constraint(
constraint_name: Optional[str],
table_name: str,
columns: Sequence[str],
*,
schema: Optional[str] = None,
**kw: Any,
) -> Any:
"""Issue a "create unique constraint" instruction using the
current migration context.
e.g.::
from alembic import op
op.create_unique_constraint("uq_user_name", "user", ["name"])
This internally generates a :class:`~sqlalchemy.schema.Table` object
containing the necessary columns, then generates a new
:class:`~sqlalchemy.schema.UniqueConstraint`
object which it then associates with the
:class:`~sqlalchemy.schema.Table`.
Any event listeners associated with this action will be fired
off normally. The :class:`~sqlalchemy.schema.AddConstraint`
construct is ultimately used to generate the ALTER statement.
:param name: Name of the unique constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param columns: a list of string column names in the
source table.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
"""
def drop_column(
table_name: str,
column_name: str,
*,
schema: Optional[str] = None,
**kw: Any,
) -> None:
"""Issue a "drop column" instruction using the current
migration context.
e.g.::
drop_column("organization", "account_id")
:param table_name: name of table
:param column_name: name of column
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
:param mssql_drop_check: Optional boolean. When ``True``, on
Microsoft SQL Server only, first
drop the CHECK constraint on the column using a
SQL-script-compatible
block that selects into a @variable from sys.check_constraints,
then exec's a separate DROP CONSTRAINT for that constraint.
:param mssql_drop_default: Optional boolean. When ``True``, on
Microsoft SQL Server only, first
drop the DEFAULT constraint on the column using a
SQL-script-compatible
block that selects into a @variable from sys.default_constraints,
then exec's a separate DROP CONSTRAINT for that default.
:param mssql_drop_foreign_key: Optional boolean. When ``True``, on
Microsoft SQL Server only, first
drop a single FOREIGN KEY constraint on the column using a
SQL-script-compatible
block that selects into a @variable from
sys.foreign_keys/sys.foreign_key_columns,
then exec's a separate DROP CONSTRAINT for that default. Only
works if the column has exactly one FK constraint which refers to
it, at the moment.
"""
def drop_constraint(
constraint_name: str,
table_name: str,
type_: Optional[str] = None,
*,
schema: Optional[str] = None,
) -> None:
r"""Drop a constraint of the given name, typically via DROP CONSTRAINT.
:param constraint_name: name of the constraint.
:param table_name: table name.
:param type\_: optional, required on MySQL. can be
'foreignkey', 'primary', 'unique', or 'check'.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
"""
def drop_index(
index_name: str,
table_name: Optional[str] = None,
*,
schema: Optional[str] = None,
**kw: Any,
) -> None:
r"""Issue a "drop index" instruction using the current
migration context.
e.g.::
drop_index("accounts")
:param index_name: name of the index.
:param table_name: name of the owning table. Some
backends such as Microsoft SQL Server require this.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
:param \**kw: Additional keyword arguments not mentioned above are
dialect specific, and passed in the form
``<dialectname>_<argname>``.
See the documentation regarding an individual dialect at
:ref:`dialect_toplevel` for detail on documented arguments.
"""
def drop_table(
table_name: str, *, schema: Optional[str] = None, **kw: Any
) -> None:
r"""Issue a "drop table" instruction using the current
migration context.
e.g.::
drop_table("accounts")
:param table_name: Name of the table
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
:param \**kw: Other keyword arguments are passed to the underlying
:class:`sqlalchemy.schema.Table` object created for the command.
"""
def drop_table_comment(
table_name: str,
*,
existing_comment: Optional[str] = None,
schema: Optional[str] = None,
) -> None:
"""Issue a "drop table comment" operation to
remove an existing comment set on a table.
.. versionadded:: 1.0.6
:param table_name: string name of the target table.
:param existing_comment: An optional string value of a comment already
registered on the specified table.
.. seealso::
:meth:`.Operations.create_table_comment`
:paramref:`.Operations.alter_column.comment`
"""
def execute(
sqltext: Union[str, TextClause, Update],
*,
execution_options: Optional[dict[str, Any]] = None,
) -> None:
r"""Execute the given SQL using the current migration context.
The given SQL can be a plain string, e.g.::
op.execute("INSERT INTO table (foo) VALUES ('some value')")
Or it can be any kind of Core SQL Expression construct, such as
below where we use an update construct::
from sqlalchemy.sql import table, column
from sqlalchemy import String
from alembic import op
account = table("account", column("name", String))
op.execute(
account.update()
.where(account.c.name == op.inline_literal("account 1"))
.values({"name": op.inline_literal("account 2")})
)
Above, we made use of the SQLAlchemy
:func:`sqlalchemy.sql.expression.table` and
:func:`sqlalchemy.sql.expression.column` constructs to make a brief,
ad-hoc table construct just for our UPDATE statement. A full
:class:`~sqlalchemy.schema.Table` construct of course works perfectly
fine as well, though note it's a recommended practice to at least
ensure the definition of a table is self-contained within the migration
script, rather than imported from a module that may break compatibility
with older migrations.
In a SQL script context, the statement is emitted directly to the
output stream. There is *no* return result, however, as this
function is oriented towards generating a change script
that can run in "offline" mode. Additionally, parameterized
statements are discouraged here, as they *will not work* in offline
mode. Above, we use :meth:`.inline_literal` where parameters are
to be used.
For full interaction with a connected database where parameters can
also be used normally, use the "bind" available from the context::
from alembic import op
connection = op.get_bind()
connection.execute(
account.update()
.where(account.c.name == "account 1")
.values({"name": "account 2"})
)
Additionally, when passing the statement as a plain string, it is first
coerceed into a :func:`sqlalchemy.sql.expression.text` construct
before being passed along. In the less likely case that the
literal SQL string contains a colon, it must be escaped with a
backslash, as::
op.execute(r"INSERT INTO table (foo) VALUES ('\:colon_value')")
:param sqltext: Any legal SQLAlchemy expression, including:
* a string
* a :func:`sqlalchemy.sql.expression.text` construct.
* a :func:`sqlalchemy.sql.expression.insert` construct.
* a :func:`sqlalchemy.sql.expression.update`,
:func:`sqlalchemy.sql.expression.insert`,
or :func:`sqlalchemy.sql.expression.delete` construct.
* Any "executable" described in SQLAlchemy Core documentation,
noting that no result set is returned.
.. note:: when passing a plain string, the statement is coerced into
a :func:`sqlalchemy.sql.expression.text` construct. This construct
considers symbols with colons, e.g. ``:foo`` to be bound parameters.
To avoid this, ensure that colon symbols are escaped, e.g.
``\:foo``.
:param execution_options: Optional dictionary of
execution options, will be passed to
:meth:`sqlalchemy.engine.Connection.execution_options`.
"""
def f(name: str) -> conv:
"""Indicate a string name that has already had a naming convention
applied to it.
This feature combines with the SQLAlchemy ``naming_convention`` feature
to disambiguate constraint names that have already had naming
conventions applied to them, versus those that have not. This is
necessary in the case that the ``"%(constraint_name)s"`` token
is used within a naming convention, so that it can be identified
that this particular name should remain fixed.
If the :meth:`.Operations.f` is used on a constraint, the naming
convention will not take effect::
op.add_column("t", "x", Boolean(name=op.f("ck_bool_t_x")))
Above, the CHECK constraint generated will have the name
``ck_bool_t_x`` regardless of whether or not a naming convention is
in use.
Alternatively, if a naming convention is in use, and 'f' is not used,
names will be converted along conventions. If the ``target_metadata``
contains the naming convention
``{"ck": "ck_bool_%(table_name)s_%(constraint_name)s"}``, then the
output of the following:
op.add_column("t", "x", Boolean(name="x"))
will be::
CONSTRAINT ck_bool_t_x CHECK (x in (1, 0)))
The function is rendered in the output of autogenerate when
a particular constraint name is already converted.
"""
def get_bind() -> Connection:
"""Return the current 'bind'.
Under normal circumstances, this is the
:class:`~sqlalchemy.engine.Connection` currently being used
to emit SQL to the database.
In a SQL script context, this value is ``None``. [TODO: verify this]
"""
def get_context() -> MigrationContext:
"""Return the :class:`.MigrationContext` object that's
currently in use.
"""
def implementation_for(op_cls: Any) -> Callable[..., Any]:
"""Register an implementation for a given :class:`.MigrateOperation`.
This is part of the operation extensibility API.
.. seealso::
:ref:`operation_plugins` - example of use
"""
def inline_literal(
value: Union[str, int], type_: Optional[TypeEngine] = None
) -> _literal_bindparam:
r"""Produce an 'inline literal' expression, suitable for
using in an INSERT, UPDATE, or DELETE statement.
When using Alembic in "offline" mode, CRUD operations
aren't compatible with SQLAlchemy's default behavior surrounding
literal values,
which is that they are converted into bound values and passed
separately into the ``execute()`` method of the DBAPI cursor.
An offline SQL
script needs to have these rendered inline. While it should
always be noted that inline literal values are an **enormous**
security hole in an application that handles untrusted input,
a schema migration is not run in this context, so
literals are safe to render inline, with the caveat that
advanced types like dates may not be supported directly
by SQLAlchemy.
See :meth:`.Operations.execute` for an example usage of
:meth:`.Operations.inline_literal`.
The environment can also be configured to attempt to render
"literal" values inline automatically, for those simple types
that are supported by the dialect; see
:paramref:`.EnvironmentContext.configure.literal_binds` for this
more recently added feature.
:param value: The value to render. Strings, integers, and simple
numerics should be supported. Other types like boolean,
dates, etc. may or may not be supported yet by various
backends.
:param type\_: optional - a :class:`sqlalchemy.types.TypeEngine`
subclass stating the type of this value. In SQLAlchemy
expressions, this is usually derived automatically
from the Python type of the value itself, as well as
based on the context in which the value is used.
.. seealso::
:paramref:`.EnvironmentContext.configure.literal_binds`
"""
def invoke(operation: MigrateOperation) -> Any:
"""Given a :class:`.MigrateOperation`, invoke it in terms of
this :class:`.Operations` instance.
"""
def register_operation(
name: str, sourcename: Optional[str] = None
) -> Callable[..., Any]:
"""Register a new operation for this class.
This method is normally used to add new operations
to the :class:`.Operations` class, and possibly the
:class:`.BatchOperations` class as well. All Alembic migration
operations are implemented via this system, however the system
is also available as a public API to facilitate adding custom
operations.
.. seealso::
:ref:`operation_plugins`
"""
def rename_table(
old_table_name: str, new_table_name: str, *, schema: Optional[str] = None
) -> None:
"""Emit an ALTER TABLE to rename a table.
:param old_table_name: old name.
:param new_table_name: new name.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
"""
def run_async(
async_function: Callable[..., Awaitable[_T]], *args: Any, **kw_args: Any
) -> _T:
"""Invoke the given asynchronous callable, passing an asynchronous
:class:`~sqlalchemy.ext.asyncio.AsyncConnection` as the first
argument.
This method allows calling async functions from within the
synchronous ``upgrade()`` or ``downgrade()`` alembic migration
method.
The async connection passed to the callable shares the same
transaction as the connection running in the migration context.
Any additional arg or kw_arg passed to this function are passed
to the provided async function.
.. versionadded: 1.11
.. note::
This method can be called only when alembic is called using
an async dialect.
"""