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from __future__ import annotations
from abc import abstractmethod
import re
from typing import Any
from typing import Callable
from typing import cast
from typing import Dict
from typing import FrozenSet
from typing import Iterator
from typing import List
from typing import MutableMapping
from typing import Optional
from typing import Sequence
from typing import Set
from typing import Tuple
from typing import Type
from typing import TYPE_CHECKING
from typing import TypeVar
from typing import Union
from sqlalchemy.types import NULLTYPE
from . import schemaobj
from .base import BatchOperations
from .base import Operations
from .. import util
from ..util import sqla_compat
if TYPE_CHECKING:
from typing import Literal
from sqlalchemy.sql import Executable
from sqlalchemy.sql.elements import ColumnElement
from sqlalchemy.sql.elements import conv
from sqlalchemy.sql.elements import quoted_name
from sqlalchemy.sql.elements import TextClause
from sqlalchemy.sql.functions import Function
from sqlalchemy.sql.schema import CheckConstraint
from sqlalchemy.sql.schema import Column
from sqlalchemy.sql.schema import Computed
from sqlalchemy.sql.schema import Constraint
from sqlalchemy.sql.schema import ForeignKeyConstraint
from sqlalchemy.sql.schema import Identity
from sqlalchemy.sql.schema import Index
from sqlalchemy.sql.schema import MetaData
from sqlalchemy.sql.schema import PrimaryKeyConstraint
from sqlalchemy.sql.schema import SchemaItem
from sqlalchemy.sql.schema import Table
from sqlalchemy.sql.schema import UniqueConstraint
from sqlalchemy.sql.selectable import TableClause
from sqlalchemy.sql.type_api import TypeEngine
from ..autogenerate.rewriter import Rewriter
from ..runtime.migration import MigrationContext
from ..script.revision import _RevIdType
_T = TypeVar("_T", bound=Any)
_AC = TypeVar("_AC", bound="AddConstraintOp")
class MigrateOperation:
"""base class for migration command and organization objects.
This system is part of the operation extensibility API.
.. seealso::
:ref:`operation_objects`
:ref:`operation_plugins`
:ref:`customizing_revision`
"""
@util.memoized_property
def info(self) -> Dict[Any, Any]:
"""A dictionary that may be used to store arbitrary information
along with this :class:`.MigrateOperation` object.
"""
return {}
_mutations: FrozenSet[Rewriter] = frozenset()
def reverse(self) -> MigrateOperation:
raise NotImplementedError
def to_diff_tuple(self) -> Tuple[Any, ...]:
raise NotImplementedError
class AddConstraintOp(MigrateOperation):
"""Represent an add constraint operation."""
add_constraint_ops = util.Dispatcher()
@property
def constraint_type(self) -> str:
raise NotImplementedError()
@classmethod
def register_add_constraint(
cls, type_: str
) -> Callable[[Type[_AC]], Type[_AC]]:
def go(klass: Type[_AC]) -> Type[_AC]:
cls.add_constraint_ops.dispatch_for(type_)(klass.from_constraint)
return klass
return go
@classmethod
def from_constraint(cls, constraint: Constraint) -> AddConstraintOp:
return cls.add_constraint_ops.dispatch(constraint.__visit_name__)( # type: ignore[no-any-return] # noqa: E501
constraint
)
@abstractmethod
def to_constraint(
self, migration_context: Optional[MigrationContext] = None
) -> Constraint:
pass
def reverse(self) -> DropConstraintOp:
return DropConstraintOp.from_constraint(self.to_constraint())
def to_diff_tuple(self) -> Tuple[str, Constraint]:
return ("add_constraint", self.to_constraint())
@Operations.register_operation("drop_constraint")
@BatchOperations.register_operation("drop_constraint", "batch_drop_constraint")
class DropConstraintOp(MigrateOperation):
"""Represent a drop constraint operation."""
def __init__(
self,
constraint_name: Optional[sqla_compat._ConstraintNameDefined],
table_name: str,
type_: Optional[str] = None,
*,
schema: Optional[str] = None,
_reverse: Optional[AddConstraintOp] = None,
) -> None:
self.constraint_name = constraint_name
self.table_name = table_name
self.constraint_type = type_
self.schema = schema
self._reverse = _reverse
def reverse(self) -> AddConstraintOp:
return AddConstraintOp.from_constraint(self.to_constraint())
def to_diff_tuple(
self,
) -> Tuple[str, SchemaItem]:
if self.constraint_type == "foreignkey":
return ("remove_fk", self.to_constraint())
else:
return ("remove_constraint", self.to_constraint())
@classmethod
def from_constraint(cls, constraint: Constraint) -> DropConstraintOp:
types = {
"unique_constraint": "unique",
"foreign_key_constraint": "foreignkey",
"primary_key_constraint": "primary",
"check_constraint": "check",
"column_check_constraint": "check",
"table_or_column_check_constraint": "check",
}
constraint_table = sqla_compat._table_for_constraint(constraint)
return cls(
sqla_compat.constraint_name_or_none(constraint.name),
constraint_table.name,
schema=constraint_table.schema,
type_=types.get(constraint.__visit_name__),
_reverse=AddConstraintOp.from_constraint(constraint),
)
def to_constraint(self) -> Constraint:
if self._reverse is not None:
constraint = self._reverse.to_constraint()
constraint.name = self.constraint_name
constraint_table = sqla_compat._table_for_constraint(constraint)
constraint_table.name = self.table_name
constraint_table.schema = self.schema
return constraint
else:
raise ValueError(
"constraint cannot be produced; "
"original constraint is not present"
)
@classmethod
def drop_constraint(
cls,
operations: Operations,
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`.
"""
op = cls(constraint_name, table_name, type_=type_, schema=schema)
return operations.invoke(op)
@classmethod
def batch_drop_constraint(
cls,
operations: BatchOperations,
constraint_name: str,
type_: Optional[str] = None,
) -> None:
"""Issue a "drop constraint" instruction using the
current batch migration context.
The batch form of this call omits the ``table_name`` and ``schema``
arguments from the call.
.. seealso::
:meth:`.Operations.drop_constraint`
"""
op = cls(
constraint_name,
operations.impl.table_name,
type_=type_,
schema=operations.impl.schema,
)
return operations.invoke(op)
@Operations.register_operation("create_primary_key")
@BatchOperations.register_operation(
"create_primary_key", "batch_create_primary_key"
)
@AddConstraintOp.register_add_constraint("primary_key_constraint")
class CreatePrimaryKeyOp(AddConstraintOp):
"""Represent a create primary key operation."""
constraint_type = "primarykey"
def __init__(
self,
constraint_name: Optional[sqla_compat._ConstraintNameDefined],
table_name: str,
columns: Sequence[str],
*,
schema: Optional[str] = None,
**kw: Any,
) -> None:
self.constraint_name = constraint_name
self.table_name = table_name
self.columns = columns
self.schema = schema
self.kw = kw
@classmethod
def from_constraint(cls, constraint: Constraint) -> CreatePrimaryKeyOp:
constraint_table = sqla_compat._table_for_constraint(constraint)
pk_constraint = cast("PrimaryKeyConstraint", constraint)
return cls(
sqla_compat.constraint_name_or_none(pk_constraint.name),
constraint_table.name,
pk_constraint.columns.keys(),
schema=constraint_table.schema,
**pk_constraint.dialect_kwargs,
)
def to_constraint(
self, migration_context: Optional[MigrationContext] = None
) -> PrimaryKeyConstraint:
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.primary_key_constraint(
self.constraint_name,
self.table_name,
self.columns,
schema=self.schema,
**self.kw,
)
@classmethod
def create_primary_key(
cls,
operations: Operations,
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`.
"""
op = cls(constraint_name, table_name, columns, schema=schema)
return operations.invoke(op)
@classmethod
def batch_create_primary_key(
cls,
operations: BatchOperations,
constraint_name: Optional[str],
columns: List[str],
) -> None:
"""Issue a "create primary key" instruction using the
current batch migration context.
The batch form of this call omits the ``table_name`` and ``schema``
arguments from the call.
.. seealso::
:meth:`.Operations.create_primary_key`
"""
op = cls(
constraint_name,
operations.impl.table_name,
columns,
schema=operations.impl.schema,
)
return operations.invoke(op)
@Operations.register_operation("create_unique_constraint")
@BatchOperations.register_operation(
"create_unique_constraint", "batch_create_unique_constraint"
)
@AddConstraintOp.register_add_constraint("unique_constraint")
class CreateUniqueConstraintOp(AddConstraintOp):
"""Represent a create unique constraint operation."""
constraint_type = "unique"
def __init__(
self,
constraint_name: Optional[sqla_compat._ConstraintNameDefined],
table_name: str,
columns: Sequence[str],
*,
schema: Optional[str] = None,
**kw: Any,
) -> None:
self.constraint_name = constraint_name
self.table_name = table_name
self.columns = columns
self.schema = schema
self.kw = kw
@classmethod
def from_constraint(
cls, constraint: Constraint
) -> CreateUniqueConstraintOp:
constraint_table = sqla_compat._table_for_constraint(constraint)
uq_constraint = cast("UniqueConstraint", constraint)
kw: Dict[str, Any] = {}
if uq_constraint.deferrable:
kw["deferrable"] = uq_constraint.deferrable
if uq_constraint.initially:
kw["initially"] = uq_constraint.initially
kw.update(uq_constraint.dialect_kwargs)
return cls(
sqla_compat.constraint_name_or_none(uq_constraint.name),
constraint_table.name,
[c.name for c in uq_constraint.columns],
schema=constraint_table.schema,
**kw,
)
def to_constraint(
self, migration_context: Optional[MigrationContext] = None
) -> UniqueConstraint:
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.unique_constraint(
self.constraint_name,
self.table_name,
self.columns,
schema=self.schema,
**self.kw,
)
@classmethod
def create_unique_constraint(
cls,
operations: Operations,
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`.
"""
op = cls(constraint_name, table_name, columns, schema=schema, **kw)
return operations.invoke(op)
@classmethod
def batch_create_unique_constraint(
cls,
operations: BatchOperations,
constraint_name: str,
columns: Sequence[str],
**kw: Any,
) -> Any:
"""Issue a "create unique constraint" instruction using the
current batch migration context.
The batch form of this call omits the ``source`` and ``schema``
arguments from the call.
.. seealso::
:meth:`.Operations.create_unique_constraint`
"""
kw["schema"] = operations.impl.schema
op = cls(constraint_name, operations.impl.table_name, columns, **kw)
return operations.invoke(op)
@Operations.register_operation("create_foreign_key")
@BatchOperations.register_operation(
"create_foreign_key", "batch_create_foreign_key"
)
@AddConstraintOp.register_add_constraint("foreign_key_constraint")
class CreateForeignKeyOp(AddConstraintOp):
"""Represent a create foreign key constraint operation."""
constraint_type = "foreignkey"
def __init__(
self,
constraint_name: Optional[sqla_compat._ConstraintNameDefined],
source_table: str,
referent_table: str,
local_cols: List[str],
remote_cols: List[str],
**kw: Any,
) -> None:
self.constraint_name = constraint_name
self.source_table = source_table
self.referent_table = referent_table
self.local_cols = local_cols
self.remote_cols = remote_cols
self.kw = kw
def to_diff_tuple(self) -> Tuple[str, ForeignKeyConstraint]:
return ("add_fk", self.to_constraint())
@classmethod
def from_constraint(cls, constraint: Constraint) -> CreateForeignKeyOp:
fk_constraint = cast("ForeignKeyConstraint", constraint)
kw: Dict[str, Any] = {}
if fk_constraint.onupdate:
kw["onupdate"] = fk_constraint.onupdate
if fk_constraint.ondelete:
kw["ondelete"] = fk_constraint.ondelete
if fk_constraint.initially:
kw["initially"] = fk_constraint.initially
if fk_constraint.deferrable:
kw["deferrable"] = fk_constraint.deferrable
if fk_constraint.use_alter:
kw["use_alter"] = fk_constraint.use_alter
if fk_constraint.match:
kw["match"] = fk_constraint.match
(
source_schema,
source_table,
source_columns,
target_schema,
target_table,
target_columns,
onupdate,
ondelete,
deferrable,
initially,
) = sqla_compat._fk_spec(fk_constraint)
kw["source_schema"] = source_schema
kw["referent_schema"] = target_schema
kw.update(fk_constraint.dialect_kwargs)
return cls(
sqla_compat.constraint_name_or_none(fk_constraint.name),
source_table,
target_table,
source_columns,
target_columns,
**kw,
)
def to_constraint(
self, migration_context: Optional[MigrationContext] = None
) -> ForeignKeyConstraint:
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.foreign_key_constraint(
self.constraint_name,
self.source_table,
self.referent_table,
self.local_cols,
self.remote_cols,
**self.kw,
)
@classmethod
def create_foreign_key(
cls,
operations: Operations,
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.
"""
op = cls(
constraint_name,
source_table,
referent_table,
local_cols,
remote_cols,
onupdate=onupdate,
ondelete=ondelete,
deferrable=deferrable,
source_schema=source_schema,
referent_schema=referent_schema,
initially=initially,
match=match,
**dialect_kw,
)
return operations.invoke(op)
@classmethod
def batch_create_foreign_key(
cls,
operations: BatchOperations,
constraint_name: Optional[str],
referent_table: str,
local_cols: List[str],
remote_cols: List[str],
*,
referent_schema: Optional[str] = None,
onupdate: Optional[str] = None,
ondelete: Optional[str] = None,
deferrable: Optional[bool] = None,
initially: Optional[str] = None,
match: Optional[str] = None,
**dialect_kw: Any,
) -> None:
"""Issue a "create foreign key" instruction using the
current batch migration context.
The batch form of this call omits the ``source`` and ``source_schema``
arguments from the call.
e.g.::
with batch_alter_table("address") as batch_op:
batch_op.create_foreign_key(
"fk_user_address",
"user",
["user_id"],
["id"],
)
.. seealso::
:meth:`.Operations.create_foreign_key`
"""
op = cls(
constraint_name,
operations.impl.table_name,
referent_table,
local_cols,
remote_cols,
onupdate=onupdate,
ondelete=ondelete,
deferrable=deferrable,
source_schema=operations.impl.schema,
referent_schema=referent_schema,
initially=initially,
match=match,
**dialect_kw,
)
return operations.invoke(op)
@Operations.register_operation("create_check_constraint")
@BatchOperations.register_operation(
"create_check_constraint", "batch_create_check_constraint"
)
@AddConstraintOp.register_add_constraint("check_constraint")
@AddConstraintOp.register_add_constraint("table_or_column_check_constraint")
@AddConstraintOp.register_add_constraint("column_check_constraint")
class CreateCheckConstraintOp(AddConstraintOp):
"""Represent a create check constraint operation."""
constraint_type = "check"
def __init__(
self,
constraint_name: Optional[sqla_compat._ConstraintNameDefined],
table_name: str,
condition: Union[str, TextClause, ColumnElement[Any]],
*,
schema: Optional[str] = None,
**kw: Any,
) -> None:
self.constraint_name = constraint_name
self.table_name = table_name
self.condition = condition
self.schema = schema
self.kw = kw
@classmethod
def from_constraint(
cls, constraint: Constraint
) -> CreateCheckConstraintOp:
constraint_table = sqla_compat._table_for_constraint(constraint)
ck_constraint = cast("CheckConstraint", constraint)
return cls(
sqla_compat.constraint_name_or_none(ck_constraint.name),
constraint_table.name,
cast("ColumnElement[Any]", ck_constraint.sqltext),
schema=constraint_table.schema,
**ck_constraint.dialect_kwargs,
)
def to_constraint(
self, migration_context: Optional[MigrationContext] = None
) -> CheckConstraint:
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.check_constraint(
self.constraint_name,
self.table_name,
self.condition,
schema=self.schema,
**self.kw,
)
@classmethod
def create_check_constraint(
cls,
operations: Operations,
constraint_name: Optional[str],
table_name: str,
condition: Union[str, ColumnElement[bool], 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`.
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
@classmethod
def batch_create_check_constraint(
cls,
operations: BatchOperations,
constraint_name: str,
condition: Union[str, ColumnElement[bool], TextClause],
**kw: Any,
) -> None:
"""Issue a "create check constraint" instruction using the
current batch migration context.
The batch form of this call omits the ``source`` and ``schema``
arguments from the call.
.. seealso::
:meth:`.Operations.create_check_constraint`
"""
op = cls(
constraint_name,
operations.impl.table_name,
condition,
schema=operations.impl.schema,
**kw,
)
return operations.invoke(op)
@Operations.register_operation("create_index")
@BatchOperations.register_operation("create_index", "batch_create_index")
class CreateIndexOp(MigrateOperation):
"""Represent a create index operation."""
def __init__(
self,
index_name: Optional[str],
table_name: str,
columns: Sequence[Union[str, TextClause, ColumnElement[Any]]],
*,
schema: Optional[str] = None,
unique: bool = False,
if_not_exists: Optional[bool] = None,
**kw: Any,
) -> None:
self.index_name = index_name
self.table_name = table_name
self.columns = columns
self.schema = schema
self.unique = unique
self.if_not_exists = if_not_exists
self.kw = kw
def reverse(self) -> DropIndexOp:
return DropIndexOp.from_index(self.to_index())
def to_diff_tuple(self) -> Tuple[str, Index]:
return ("add_index", self.to_index())
@classmethod
def from_index(cls, index: Index) -> CreateIndexOp:
assert index.table is not None
return cls(
index.name,
index.table.name,
index.expressions,
schema=index.table.schema,
unique=index.unique,
**index.kwargs,
)
def to_index(
self, migration_context: Optional[MigrationContext] = None
) -> Index:
schema_obj = schemaobj.SchemaObjects(migration_context)
idx = schema_obj.index(
self.index_name,
self.table_name,
self.columns,
schema=self.schema,
unique=self.unique,
**self.kw,
)
return idx
@classmethod
def create_index(
cls,
operations: Operations,
index_name: Optional[str],
table_name: str,
columns: Sequence[Union[str, TextClause, Function[Any]]],
*,
schema: Optional[str] = None,
unique: bool = False,
if_not_exists: Optional[bool] = None,
**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 if_not_exists: If True, adds IF NOT EXISTS operator when
creating the new index.
.. versionadded:: 1.12.0
: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.
"""
op = cls(
index_name,
table_name,
columns,
schema=schema,
unique=unique,
if_not_exists=if_not_exists,
**kw,
)
return operations.invoke(op)
@classmethod
def batch_create_index(
cls,
operations: BatchOperations,
index_name: str,
columns: List[str],
**kw: Any,
) -> None:
"""Issue a "create index" instruction using the
current batch migration context.
.. seealso::
:meth:`.Operations.create_index`
"""
op = cls(
index_name,
operations.impl.table_name,
columns,
schema=operations.impl.schema,
**kw,
)
return operations.invoke(op)
@Operations.register_operation("drop_index")
@BatchOperations.register_operation("drop_index", "batch_drop_index")
class DropIndexOp(MigrateOperation):
"""Represent a drop index operation."""
def __init__(
self,
index_name: Union[quoted_name, str, conv],
table_name: Optional[str] = None,
*,
schema: Optional[str] = None,
if_exists: Optional[bool] = None,
_reverse: Optional[CreateIndexOp] = None,
**kw: Any,
) -> None:
self.index_name = index_name
self.table_name = table_name
self.schema = schema
self.if_exists = if_exists
self._reverse = _reverse
self.kw = kw
def to_diff_tuple(self) -> Tuple[str, Index]:
return ("remove_index", self.to_index())
def reverse(self) -> CreateIndexOp:
return CreateIndexOp.from_index(self.to_index())
@classmethod
def from_index(cls, index: Index) -> DropIndexOp:
assert index.table is not None
return cls(
index.name, # type: ignore[arg-type]
table_name=index.table.name,
schema=index.table.schema,
_reverse=CreateIndexOp.from_index(index),
unique=index.unique,
**index.kwargs,
)
def to_index(
self, migration_context: Optional[MigrationContext] = None
) -> Index:
schema_obj = schemaobj.SchemaObjects(migration_context)
# need a dummy column name here since SQLAlchemy
# 0.7.6 and further raises on Index with no columns
return schema_obj.index(
self.index_name,
self.table_name,
self._reverse.columns if self._reverse else ["x"],
schema=self.schema,
**self.kw,
)
@classmethod
def drop_index(
cls,
operations: Operations,
index_name: str,
table_name: Optional[str] = None,
*,
schema: Optional[str] = None,
if_exists: Optional[bool] = 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 if_exists: If True, adds IF EXISTS operator when
dropping the index.
.. versionadded:: 1.12.0
: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.
"""
op = cls(
index_name,
table_name=table_name,
schema=schema,
if_exists=if_exists,
**kw,
)
return operations.invoke(op)
@classmethod
def batch_drop_index(
cls, operations: BatchOperations, index_name: str, **kw: Any
) -> None:
"""Issue a "drop index" instruction using the
current batch migration context.
.. seealso::
:meth:`.Operations.drop_index`
"""
op = cls(
index_name,
table_name=operations.impl.table_name,
schema=operations.impl.schema,
**kw,
)
return operations.invoke(op)
@Operations.register_operation("create_table")
class CreateTableOp(MigrateOperation):
"""Represent a create table operation."""
def __init__(
self,
table_name: str,
columns: Sequence[SchemaItem],
*,
schema: Optional[str] = None,
_namespace_metadata: Optional[MetaData] = None,
_constraints_included: bool = False,
**kw: Any,
) -> None:
self.table_name = table_name
self.columns = columns
self.schema = schema
self.info = kw.pop("info", {})
self.comment = kw.pop("comment", None)
self.prefixes = kw.pop("prefixes", None)
self.kw = kw
self._namespace_metadata = _namespace_metadata
self._constraints_included = _constraints_included
def reverse(self) -> DropTableOp:
return DropTableOp.from_table(
self.to_table(), _namespace_metadata=self._namespace_metadata
)
def to_diff_tuple(self) -> Tuple[str, Table]:
return ("add_table", self.to_table())
@classmethod
def from_table(
cls, table: Table, *, _namespace_metadata: Optional[MetaData] = None
) -> CreateTableOp:
if _namespace_metadata is None:
_namespace_metadata = table.metadata
return cls(
table.name,
list(table.c) + list(table.constraints),
schema=table.schema,
_namespace_metadata=_namespace_metadata,
# given a Table() object, this Table will contain full Index()
# and UniqueConstraint objects already constructed in response to
# each unique=True / index=True flag on a Column. Carry this
# state along so that when we re-convert back into a Table, we
# skip unique=True/index=True so that these constraints are
# not doubled up. see #844 #848
_constraints_included=True,
comment=table.comment,
info=dict(table.info),
prefixes=list(table._prefixes),
**table.kwargs,
)
def to_table(
self, migration_context: Optional[MigrationContext] = None
) -> Table:
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.table(
self.table_name,
*self.columns,
schema=self.schema,
prefixes=list(self.prefixes) if self.prefixes else [],
comment=self.comment,
info=self.info.copy() if self.info else {},
_constraints_included=self._constraints_included,
**self.kw,
)
@classmethod
def create_table(
cls,
operations: Operations,
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.
"""
op = cls(table_name, columns, **kw)
return operations.invoke(op)
@Operations.register_operation("drop_table")
class DropTableOp(MigrateOperation):
"""Represent a drop table operation."""
def __init__(
self,
table_name: str,
*,
schema: Optional[str] = None,
table_kw: Optional[MutableMapping[Any, Any]] = None,
_reverse: Optional[CreateTableOp] = None,
) -> None:
self.table_name = table_name
self.schema = schema
self.table_kw = table_kw or {}
self.comment = self.table_kw.pop("comment", None)
self.info = self.table_kw.pop("info", None)
self.prefixes = self.table_kw.pop("prefixes", None)
self._reverse = _reverse
def to_diff_tuple(self) -> Tuple[str, Table]:
return ("remove_table", self.to_table())
def reverse(self) -> CreateTableOp:
return CreateTableOp.from_table(self.to_table())
@classmethod
def from_table(
cls, table: Table, *, _namespace_metadata: Optional[MetaData] = None
) -> DropTableOp:
return cls(
table.name,
schema=table.schema,
table_kw={
"comment": table.comment,
"info": dict(table.info),
"prefixes": list(table._prefixes),
**table.kwargs,
},
_reverse=CreateTableOp.from_table(
table, _namespace_metadata=_namespace_metadata
),
)
def to_table(
self, migration_context: Optional[MigrationContext] = None
) -> Table:
if self._reverse:
cols_and_constraints = self._reverse.columns
else:
cols_and_constraints = []
schema_obj = schemaobj.SchemaObjects(migration_context)
t = schema_obj.table(
self.table_name,
*cols_and_constraints,
comment=self.comment,
info=self.info.copy() if self.info else {},
prefixes=list(self.prefixes) if self.prefixes else [],
schema=self.schema,
_constraints_included=(
self._reverse._constraints_included if self._reverse else False
),
**self.table_kw,
)
return t
@classmethod
def drop_table(
cls,
operations: Operations,
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.
"""
op = cls(table_name, schema=schema, table_kw=kw)
operations.invoke(op)
class AlterTableOp(MigrateOperation):
"""Represent an alter table operation."""
def __init__(
self,
table_name: str,
*,
schema: Optional[str] = None,
) -> None:
self.table_name = table_name
self.schema = schema
@Operations.register_operation("rename_table")
class RenameTableOp(AlterTableOp):
"""Represent a rename table operation."""
def __init__(
self,
old_table_name: str,
new_table_name: str,
*,
schema: Optional[str] = None,
) -> None:
super().__init__(old_table_name, schema=schema)
self.new_table_name = new_table_name
@classmethod
def rename_table(
cls,
operations: Operations,
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`.
"""
op = cls(old_table_name, new_table_name, schema=schema)
return operations.invoke(op)
@Operations.register_operation("create_table_comment")
@BatchOperations.register_operation(
"create_table_comment", "batch_create_table_comment"
)
class CreateTableCommentOp(AlterTableOp):
"""Represent a COMMENT ON `table` operation."""
def __init__(
self,
table_name: str,
comment: Optional[str],
*,
schema: Optional[str] = None,
existing_comment: Optional[str] = None,
) -> None:
self.table_name = table_name
self.comment = comment
self.existing_comment = existing_comment
self.schema = schema
@classmethod
def create_table_comment(
cls,
operations: Operations,
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.
: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`
"""
op = cls(
table_name,
comment,
existing_comment=existing_comment,
schema=schema,
)
return operations.invoke(op)
@classmethod
def batch_create_table_comment(
cls,
operations: BatchOperations,
comment: Optional[str],
*,
existing_comment: Optional[str] = None,
) -> None:
"""Emit a COMMENT ON operation to set the comment for a table
using the current batch migration context.
: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.
"""
op = cls(
operations.impl.table_name,
comment,
existing_comment=existing_comment,
schema=operations.impl.schema,
)
return operations.invoke(op)
def reverse(self) -> Union[CreateTableCommentOp, DropTableCommentOp]:
"""Reverses the COMMENT ON operation against a table."""
if self.existing_comment is None:
return DropTableCommentOp(
self.table_name,
existing_comment=self.comment,
schema=self.schema,
)
else:
return CreateTableCommentOp(
self.table_name,
self.existing_comment,
existing_comment=self.comment,
schema=self.schema,
)
def to_table(
self, migration_context: Optional[MigrationContext] = None
) -> Table:
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.table(
self.table_name, schema=self.schema, comment=self.comment
)
def to_diff_tuple(self) -> Tuple[Any, ...]:
return ("add_table_comment", self.to_table(), self.existing_comment)
@Operations.register_operation("drop_table_comment")
@BatchOperations.register_operation(
"drop_table_comment", "batch_drop_table_comment"
)
class DropTableCommentOp(AlterTableOp):
"""Represent an operation to remove the comment from a table."""
def __init__(
self,
table_name: str,
*,
schema: Optional[str] = None,
existing_comment: Optional[str] = None,
) -> None:
self.table_name = table_name
self.existing_comment = existing_comment
self.schema = schema
@classmethod
def drop_table_comment(
cls,
operations: Operations,
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.
: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`
"""
op = cls(table_name, existing_comment=existing_comment, schema=schema)
return operations.invoke(op)
@classmethod
def batch_drop_table_comment(
cls,
operations: BatchOperations,
*,
existing_comment: Optional[str] = None,
) -> None:
"""Issue a "drop table comment" operation to
remove an existing comment set on a table using the current
batch operations context.
:param existing_comment: An optional string value of a comment already
registered on the specified table.
"""
op = cls(
operations.impl.table_name,
existing_comment=existing_comment,
schema=operations.impl.schema,
)
return operations.invoke(op)
def reverse(self) -> CreateTableCommentOp:
"""Reverses the COMMENT ON operation against a table."""
return CreateTableCommentOp(
self.table_name, self.existing_comment, schema=self.schema
)
def to_table(
self, migration_context: Optional[MigrationContext] = None
) -> Table:
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.table(self.table_name, schema=self.schema)
def to_diff_tuple(self) -> Tuple[Any, ...]:
return ("remove_table_comment", self.to_table())
@Operations.register_operation("alter_column")
@BatchOperations.register_operation("alter_column", "batch_alter_column")
class AlterColumnOp(AlterTableOp):
"""Represent an alter column operation."""
def __init__(
self,
table_name: str,
column_name: str,
*,
schema: Optional[str] = None,
existing_type: Optional[Any] = None,
existing_server_default: Any = False,
existing_nullable: Optional[bool] = None,
existing_comment: Optional[str] = None,
modify_nullable: Optional[bool] = None,
modify_comment: Optional[Union[str, Literal[False]]] = False,
modify_server_default: Any = False,
modify_name: Optional[str] = None,
modify_type: Optional[Any] = None,
**kw: Any,
) -> None:
super().__init__(table_name, schema=schema)
self.column_name = column_name
self.existing_type = existing_type
self.existing_server_default = existing_server_default
self.existing_nullable = existing_nullable
self.existing_comment = existing_comment
self.modify_nullable = modify_nullable
self.modify_comment = modify_comment
self.modify_server_default = modify_server_default
self.modify_name = modify_name
self.modify_type = modify_type
self.kw = kw
def to_diff_tuple(self) -> Any:
col_diff = []
schema, tname, cname = self.schema, self.table_name, self.column_name
if self.modify_type is not None:
col_diff.append(
(
"modify_type",
schema,
tname,
cname,
{
"existing_nullable": self.existing_nullable,
"existing_server_default": (
self.existing_server_default
),
"existing_comment": self.existing_comment,
},
self.existing_type,
self.modify_type,
)
)
if self.modify_nullable is not None:
col_diff.append(
(
"modify_nullable",
schema,
tname,
cname,
{
"existing_type": self.existing_type,
"existing_server_default": (
self.existing_server_default
),
"existing_comment": self.existing_comment,
},
self.existing_nullable,
self.modify_nullable,
)
)
if self.modify_server_default is not False:
col_diff.append(
(
"modify_default",
schema,
tname,
cname,
{
"existing_nullable": self.existing_nullable,
"existing_type": self.existing_type,
"existing_comment": self.existing_comment,
},
self.existing_server_default,
self.modify_server_default,
)
)
if self.modify_comment is not False:
col_diff.append(
(
"modify_comment",
schema,
tname,
cname,
{
"existing_nullable": self.existing_nullable,
"existing_type": self.existing_type,
"existing_server_default": (
self.existing_server_default
),
},
self.existing_comment,
self.modify_comment,
)
)
return col_diff
def has_changes(self) -> bool:
hc1 = (
self.modify_nullable is not None
or self.modify_server_default is not False
or self.modify_type is not None
or self.modify_comment is not False
)
if hc1:
return True
for kw in self.kw:
if kw.startswith("modify_"):
return True
else:
return False
def reverse(self) -> AlterColumnOp:
kw = self.kw.copy()
kw["existing_type"] = self.existing_type
kw["existing_nullable"] = self.existing_nullable
kw["existing_server_default"] = self.existing_server_default
kw["existing_comment"] = self.existing_comment
if self.modify_type is not None:
kw["modify_type"] = self.modify_type
if self.modify_nullable is not None:
kw["modify_nullable"] = self.modify_nullable
if self.modify_server_default is not False:
kw["modify_server_default"] = self.modify_server_default
if self.modify_comment is not False:
kw["modify_comment"] = self.modify_comment
# TODO: make this a little simpler
all_keys = {
m.group(1)
for m in [re.match(r"^(?:existing_|modify_)(.+)$", k) for k in kw]
if m
}
for k in all_keys:
if "modify_%s" % k in kw:
swap = kw["existing_%s" % k]
kw["existing_%s" % k] = kw["modify_%s" % k]
kw["modify_%s" % k] = swap
return self.__class__(
self.table_name, self.column_name, schema=self.schema, **kw
)
@classmethod
def alter_column(
cls,
operations: Operations,
table_name: str,
column_name: str,
*,
nullable: Optional[bool] = None,
comment: Optional[Union[str, Literal[False]]] = False,
server_default: Any = False,
new_column_name: Optional[str] = None,
type_: Optional[Union[TypeEngine[Any], Type[TypeEngine[Any]]]] = None,
existing_type: Optional[
Union[TypeEngine[Any], Type[TypeEngine[Any]]]
] = None,
existing_server_default: Optional[
Union[str, bool, Identity, Computed]
] = 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.
: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
SQLAlchemy "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.
: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.
"""
alt = cls(
table_name,
column_name,
schema=schema,
existing_type=existing_type,
existing_server_default=existing_server_default,
existing_nullable=existing_nullable,
existing_comment=existing_comment,
modify_name=new_column_name,
modify_type=type_,
modify_server_default=server_default,
modify_nullable=nullable,
modify_comment=comment,
**kw,
)
return operations.invoke(alt)
@classmethod
def batch_alter_column(
cls,
operations: BatchOperations,
column_name: str,
*,
nullable: Optional[bool] = None,
comment: Optional[Union[str, Literal[False]]] = False,
server_default: Any = False,
new_column_name: Optional[str] = None,
type_: Optional[Union[TypeEngine[Any], Type[TypeEngine[Any]]]] = None,
existing_type: Optional[
Union[TypeEngine[Any], Type[TypeEngine[Any]]]
] = None,
existing_server_default: Optional[
Union[str, bool, Identity, Computed]
] = False,
existing_nullable: Optional[bool] = None,
existing_comment: Optional[str] = None,
insert_before: Optional[str] = None,
insert_after: Optional[str] = None,
**kw: Any,
) -> None:
"""Issue an "alter column" instruction using the current
batch migration context.
Parameters are the same as that of :meth:`.Operations.alter_column`,
as well as the following option(s):
:param insert_before: String name of an existing column which this
column should be placed before, when creating the new table.
:param insert_after: String name of an existing column which this
column should be placed after, when creating the new table. If
both :paramref:`.BatchOperations.alter_column.insert_before`
and :paramref:`.BatchOperations.alter_column.insert_after` are
omitted, the column is inserted after the last existing column
in the table.
.. seealso::
:meth:`.Operations.alter_column`
"""
alt = cls(
operations.impl.table_name,
column_name,
schema=operations.impl.schema,
existing_type=existing_type,
existing_server_default=existing_server_default,
existing_nullable=existing_nullable,
existing_comment=existing_comment,
modify_name=new_column_name,
modify_type=type_,
modify_server_default=server_default,
modify_nullable=nullable,
modify_comment=comment,
insert_before=insert_before,
insert_after=insert_after,
**kw,
)
return operations.invoke(alt)
@Operations.register_operation("add_column")
@BatchOperations.register_operation("add_column", "batch_add_column")
class AddColumnOp(AlterTableOp):
"""Represent an add column operation."""
def __init__(
self,
table_name: str,
column: Column[Any],
*,
schema: Optional[str] = None,
**kw: Any,
) -> None:
super().__init__(table_name, schema=schema)
self.column = column
self.kw = kw
def reverse(self) -> DropColumnOp:
return DropColumnOp.from_column_and_tablename(
self.schema, self.table_name, self.column
)
def to_diff_tuple(
self,
) -> Tuple[str, Optional[str], str, Column[Any]]:
return ("add_column", self.schema, self.table_name, self.column)
def to_column(self) -> Column[Any]:
return self.column
@classmethod
def from_column(cls, col: Column[Any]) -> AddColumnOp:
return cls(col.table.name, col, schema=col.table.schema)
@classmethod
def from_column_and_tablename(
cls,
schema: Optional[str],
tname: str,
col: Column[Any],
) -> AddColumnOp:
return cls(tname, col, schema=schema)
@classmethod
def add_column(
cls,
operations: Operations,
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`.
"""
op = cls(table_name, column, schema=schema)
return operations.invoke(op)
@classmethod
def batch_add_column(
cls,
operations: BatchOperations,
column: Column[Any],
*,
insert_before: Optional[str] = None,
insert_after: Optional[str] = None,
) -> None:
"""Issue an "add column" instruction using the current
batch migration context.
.. seealso::
:meth:`.Operations.add_column`
"""
kw = {}
if insert_before:
kw["insert_before"] = insert_before
if insert_after:
kw["insert_after"] = insert_after
op = cls(
operations.impl.table_name,
column,
schema=operations.impl.schema,
**kw,
)
return operations.invoke(op)
@Operations.register_operation("drop_column")
@BatchOperations.register_operation("drop_column", "batch_drop_column")
class DropColumnOp(AlterTableOp):
"""Represent a drop column operation."""
def __init__(
self,
table_name: str,
column_name: str,
*,
schema: Optional[str] = None,
_reverse: Optional[AddColumnOp] = None,
**kw: Any,
) -> None:
super().__init__(table_name, schema=schema)
self.column_name = column_name
self.kw = kw
self._reverse = _reverse
def to_diff_tuple(
self,
) -> Tuple[str, Optional[str], str, Column[Any]]:
return (
"remove_column",
self.schema,
self.table_name,
self.to_column(),
)
def reverse(self) -> AddColumnOp:
if self._reverse is None:
raise ValueError(
"operation is not reversible; "
"original column is not present"
)
return AddColumnOp.from_column_and_tablename(
self.schema, self.table_name, self._reverse.column
)
@classmethod
def from_column_and_tablename(
cls,
schema: Optional[str],
tname: str,
col: Column[Any],
) -> DropColumnOp:
return cls(
tname,
col.name,
schema=schema,
_reverse=AddColumnOp.from_column_and_tablename(schema, tname, col),
)
def to_column(
self, migration_context: Optional[MigrationContext] = None
) -> Column[Any]:
if self._reverse is not None:
return self._reverse.column
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.column(self.column_name, NULLTYPE)
@classmethod
def drop_column(
cls,
operations: Operations,
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.
"""
op = cls(table_name, column_name, schema=schema, **kw)
return operations.invoke(op)
@classmethod
def batch_drop_column(
cls, operations: BatchOperations, column_name: str, **kw: Any
) -> None:
"""Issue a "drop column" instruction using the current
batch migration context.
.. seealso::
:meth:`.Operations.drop_column`
"""
op = cls(
operations.impl.table_name,
column_name,
schema=operations.impl.schema,
**kw,
)
return operations.invoke(op)
@Operations.register_operation("bulk_insert")
class BulkInsertOp(MigrateOperation):
"""Represent a bulk insert operation."""
def __init__(
self,
table: Union[Table, TableClause],
rows: List[Dict[str, Any]],
*,
multiinsert: bool = True,
) -> None:
self.table = table
self.rows = rows
self.multiinsert = multiinsert
@classmethod
def bulk_insert(
cls,
operations: Operations,
table: Union[Table, TableClause],
rows: List[Dict[str, Any]],
*,
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.
"""
op = cls(table, rows, multiinsert=multiinsert)
operations.invoke(op)
@Operations.register_operation("execute")
@BatchOperations.register_operation("execute", "batch_execute")
class ExecuteSQLOp(MigrateOperation):
"""Represent an execute SQL operation."""
def __init__(
self,
sqltext: Union[Executable, str],
*,
execution_options: Optional[dict[str, Any]] = None,
) -> None:
self.sqltext = sqltext
self.execution_options = execution_options
@classmethod
def execute(
cls,
operations: Operations,
sqltext: Union[Executable, str],
*,
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
coerced 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` construct.
* a :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`.
"""
op = cls(sqltext, execution_options=execution_options)
return operations.invoke(op)
@classmethod
def batch_execute(
cls,
operations: Operations,
sqltext: Union[Executable, str],
*,
execution_options: Optional[dict[str, Any]] = None,
) -> None:
"""Execute the given SQL using the current migration context.
.. seealso::
:meth:`.Operations.execute`
"""
return cls.execute(
operations, sqltext, execution_options=execution_options
)
def to_diff_tuple(self) -> Tuple[str, Union[Executable, str]]:
return ("execute", self.sqltext)
class OpContainer(MigrateOperation):
"""Represent a sequence of operations operation."""
def __init__(self, ops: Sequence[MigrateOperation] = ()) -> None:
self.ops = list(ops)
def is_empty(self) -> bool:
return not self.ops
def as_diffs(self) -> Any:
return list(OpContainer._ops_as_diffs(self))
@classmethod
def _ops_as_diffs(
cls, migrations: OpContainer
) -> Iterator[Tuple[Any, ...]]:
for op in migrations.ops:
if hasattr(op, "ops"):
yield from cls._ops_as_diffs(cast("OpContainer", op))
else:
yield op.to_diff_tuple()
class ModifyTableOps(OpContainer):
"""Contains a sequence of operations that all apply to a single Table."""
def __init__(
self,
table_name: str,
ops: Sequence[MigrateOperation],
*,
schema: Optional[str] = None,
) -> None:
super().__init__(ops)
self.table_name = table_name
self.schema = schema
def reverse(self) -> ModifyTableOps:
return ModifyTableOps(
self.table_name,
ops=list(reversed([op.reverse() for op in self.ops])),
schema=self.schema,
)
class UpgradeOps(OpContainer):
"""contains a sequence of operations that would apply to the
'upgrade' stream of a script.
.. seealso::
:ref:`customizing_revision`
"""
def __init__(
self,
ops: Sequence[MigrateOperation] = (),
upgrade_token: str = "upgrades",
) -> None:
super().__init__(ops=ops)
self.upgrade_token = upgrade_token
def reverse_into(self, downgrade_ops: DowngradeOps) -> DowngradeOps:
downgrade_ops.ops[:] = list(
reversed([op.reverse() for op in self.ops])
)
return downgrade_ops
def reverse(self) -> DowngradeOps:
return self.reverse_into(DowngradeOps(ops=[]))
class DowngradeOps(OpContainer):
"""contains a sequence of operations that would apply to the
'downgrade' stream of a script.
.. seealso::
:ref:`customizing_revision`
"""
def __init__(
self,
ops: Sequence[MigrateOperation] = (),
downgrade_token: str = "downgrades",
) -> None:
super().__init__(ops=ops)
self.downgrade_token = downgrade_token
def reverse(self) -> UpgradeOps:
return UpgradeOps(
ops=list(reversed([op.reverse() for op in self.ops]))
)
class MigrationScript(MigrateOperation):
"""represents a migration script.
E.g. when autogenerate encounters this object, this corresponds to the
production of an actual script file.
A normal :class:`.MigrationScript` object would contain a single
:class:`.UpgradeOps` and a single :class:`.DowngradeOps` directive.
These are accessible via the ``.upgrade_ops`` and ``.downgrade_ops``
attributes.
In the case of an autogenerate operation that runs multiple times,
such as the multiple database example in the "multidb" template,
the ``.upgrade_ops`` and ``.downgrade_ops`` attributes are disabled,
and instead these objects should be accessed via the ``.upgrade_ops_list``
and ``.downgrade_ops_list`` list-based attributes. These latter
attributes are always available at the very least as single-element lists.
.. seealso::
:ref:`customizing_revision`
"""
_needs_render: Optional[bool]
_upgrade_ops: List[UpgradeOps]
_downgrade_ops: List[DowngradeOps]
def __init__(
self,
rev_id: Optional[str],
upgrade_ops: UpgradeOps,
downgrade_ops: DowngradeOps,
*,
message: Optional[str] = None,
imports: Set[str] = set(),
head: Optional[str] = None,
splice: Optional[bool] = None,
branch_label: Optional[_RevIdType] = None,
version_path: Optional[str] = None,
depends_on: Optional[_RevIdType] = None,
) -> None:
self.rev_id = rev_id
self.message = message
self.imports = imports
self.head = head
self.splice = splice
self.branch_label = branch_label
self.version_path = version_path
self.depends_on = depends_on
self.upgrade_ops = upgrade_ops
self.downgrade_ops = downgrade_ops
@property
def upgrade_ops(self) -> Optional[UpgradeOps]:
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute."
)
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
@upgrade_ops.setter
def upgrade_ops(
self, upgrade_ops: Union[UpgradeOps, List[UpgradeOps]]
) -> None:
self._upgrade_ops = util.to_list(upgrade_ops)
for elem in self._upgrade_ops:
assert isinstance(elem, UpgradeOps)
@property
def downgrade_ops(self) -> Optional[DowngradeOps]:
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute."
)
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
@downgrade_ops.setter
def downgrade_ops(
self, downgrade_ops: Union[DowngradeOps, List[DowngradeOps]]
) -> None:
self._downgrade_ops = util.to_list(downgrade_ops)
for elem in self._downgrade_ops:
assert isinstance(elem, DowngradeOps)
@property
def upgrade_ops_list(self) -> List[UpgradeOps]:
"""A list of :class:`.UpgradeOps` instances.
This is used in place of the :attr:`.MigrationScript.upgrade_ops`
attribute when dealing with a revision operation that does
multiple autogenerate passes.
"""
return self._upgrade_ops
@property
def downgrade_ops_list(self) -> List[DowngradeOps]:
"""A list of :class:`.DowngradeOps` instances.
This is used in place of the :attr:`.MigrationScript.downgrade_ops`
attribute when dealing with a revision operation that does
multiple autogenerate passes.
"""
return self._downgrade_ops