Current File : //proc/thread-self/root/opt/alt/python37/lib/python3.7/site-packages/alembic/operations/ops.py
from .. import util
from ..util import sqla_compat
from . import schemaobj
from sqlalchemy.types import NULLTYPE
from .base import Operations, BatchOperations
import re
class MigrateOperation(object):
"""base class for migration command and organization objects.
This system is part of the operation extensibility API.
.. versionadded:: 0.8.0
.. seealso::
:ref:`operation_objects`
:ref:`operation_plugins`
:ref:`customizing_revision`
"""
@util.memoized_property
def info(self):
"""A dictionary that may be used to store arbitrary information
along with this :class:`.MigrateOperation` object.
"""
return {}
class AddConstraintOp(MigrateOperation):
"""Represent an add constraint operation."""
@property
def constraint_type(self):
raise NotImplementedError()
@classmethod
def from_constraint(cls, constraint):
funcs = {
"unique_constraint": CreateUniqueConstraintOp.from_constraint,
"foreign_key_constraint": CreateForeignKeyOp.from_constraint,
"primary_key_constraint": CreatePrimaryKeyOp.from_constraint,
"check_constraint": CreateCheckConstraintOp.from_constraint,
"column_check_constraint": CreateCheckConstraintOp.from_constraint,
}
return funcs[constraint.__visit_name__](constraint)
def reverse(self):
return DropConstraintOp.from_constraint(self.to_constraint())
def to_diff_tuple(self):
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, table_name, type_=None, schema=None,
_orig_constraint=None):
self.constraint_name = constraint_name
self.table_name = table_name
self.constraint_type = type_
self.schema = schema
self._orig_constraint = _orig_constraint
def reverse(self):
if self._orig_constraint is None:
raise ValueError(
"operation is not reversible; "
"original constraint is not present")
return AddConstraintOp.from_constraint(self._orig_constraint)
def to_diff_tuple(self):
if self.constraint_type == "foreignkey":
return ("remove_fk", self.to_constraint())
else:
return ("remove_constraint", self.to_constraint())
@classmethod
def from_constraint(cls, constraint):
types = {
"unique_constraint": "unique",
"foreign_key_constraint": "foreignkey",
"primary_key_constraint": "primary",
"check_constraint": "check",
"column_check_constraint": "check",
}
constraint_table = sqla_compat._table_for_constraint(constraint)
return cls(
constraint.name,
constraint_table.name,
schema=constraint_table.schema,
type_=types[constraint.__visit_name__],
_orig_constraint=constraint
)
def to_constraint(self):
if self._orig_constraint is not None:
return self._orig_constraint
else:
raise ValueError(
"constraint cannot be produced; "
"original constraint is not present")
@classmethod
@util._with_legacy_names([
("type", "type_"),
("name", "constraint_name"),
])
def drop_constraint(
cls, operations, constraint_name, table_name,
type_=None, schema=None):
"""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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
"""
op = cls(constraint_name, table_name, type_=type_, schema=schema)
return operations.invoke(op)
@classmethod
def batch_drop_constraint(cls, operations, constraint_name, type_=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`
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
"""
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")
class CreatePrimaryKeyOp(AddConstraintOp):
"""Represent a create primary key operation."""
constraint_type = "primarykey"
def __init__(
self, constraint_name, table_name, columns,
schema=None, _orig_constraint=None, **kw):
self.constraint_name = constraint_name
self.table_name = table_name
self.columns = columns
self.schema = schema
self._orig_constraint = _orig_constraint
self.kw = kw
@classmethod
def from_constraint(cls, constraint):
constraint_table = sqla_compat._table_for_constraint(constraint)
return cls(
constraint.name,
constraint_table.name,
constraint.columns,
schema=constraint_table.schema,
_orig_constraint=constraint
)
def to_constraint(self, migration_context=None):
if self._orig_constraint is not None:
return self._orig_constraint
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.primary_key_constraint(
self.constraint_name, self.table_name,
self.columns, schema=self.schema)
@classmethod
@util._with_legacy_names([
('name', 'constraint_name'),
('cols', 'columns')
])
def create_primary_key(
cls, operations,
constraint_name, table_name, columns, schema=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 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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* cols -> columns
"""
op = cls(constraint_name, table_name, columns, schema)
return operations.invoke(op)
@classmethod
def batch_create_primary_key(cls, operations, constraint_name, columns):
"""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")
class CreateUniqueConstraintOp(AddConstraintOp):
"""Represent a create unique constraint operation."""
constraint_type = "unique"
def __init__(
self, constraint_name, table_name,
columns, schema=None, _orig_constraint=None, **kw):
self.constraint_name = constraint_name
self.table_name = table_name
self.columns = columns
self.schema = schema
self._orig_constraint = _orig_constraint
self.kw = kw
@classmethod
def from_constraint(cls, constraint):
constraint_table = sqla_compat._table_for_constraint(constraint)
kw = {}
if constraint.deferrable:
kw['deferrable'] = constraint.deferrable
if constraint.initially:
kw['initially'] = constraint.initially
return cls(
constraint.name,
constraint_table.name,
[c.name for c in constraint.columns],
schema=constraint_table.schema,
_orig_constraint=constraint,
**kw
)
def to_constraint(self, migration_context=None):
if self._orig_constraint is not None:
return self._orig_constraint
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
@util._with_legacy_names([
('name', 'constraint_name'),
('source', 'table_name'),
('local_cols', 'columns'),
])
def create_unique_constraint(
cls, operations, constraint_name, table_name, columns,
schema=None, **kw):
"""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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
* local_cols -> columns
"""
op = cls(
constraint_name, table_name, columns,
schema=schema, **kw
)
return operations.invoke(op)
@classmethod
@util._with_legacy_names([('name', 'constraint_name')])
def batch_create_unique_constraint(
cls, operations, constraint_name, columns, **kw):
"""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`
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
"""
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")
class CreateForeignKeyOp(AddConstraintOp):
"""Represent a create foreign key constraint operation."""
constraint_type = "foreignkey"
def __init__(
self, constraint_name, source_table, referent_table, local_cols,
remote_cols, _orig_constraint=None, **kw):
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._orig_constraint = _orig_constraint
self.kw = kw
def to_diff_tuple(self):
return ("add_fk", self.to_constraint())
@classmethod
def from_constraint(cls, constraint):
kw = {}
if constraint.onupdate:
kw['onupdate'] = constraint.onupdate
if constraint.ondelete:
kw['ondelete'] = constraint.ondelete
if constraint.initially:
kw['initially'] = constraint.initially
if constraint.deferrable:
kw['deferrable'] = constraint.deferrable
if constraint.use_alter:
kw['use_alter'] = constraint.use_alter
source_schema, source_table, \
source_columns, target_schema, \
target_table, target_columns,\
onupdate, ondelete, deferrable, initially \
= sqla_compat._fk_spec(constraint)
kw['source_schema'] = source_schema
kw['referent_schema'] = target_schema
return cls(
constraint.name,
source_table,
target_table,
source_columns,
target_columns,
_orig_constraint=constraint,
**kw
)
def to_constraint(self, migration_context=None):
if self._orig_constraint is not None:
return self._orig_constraint
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
@util._with_legacy_names([
('name', 'constraint_name'),
('source', 'source_table'),
('referent', 'referent_table'),
])
def create_foreign_key(cls, operations, constraint_name,
source_table, referent_table, local_cols,
remote_cols, onupdate=None, ondelete=None,
deferrable=None, initially=None, match=None,
source_schema=None, referent_schema=None,
**dialect_kw):
"""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 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.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> source_table
* referent -> referent_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
@util._with_legacy_names([
('name', 'constraint_name'),
('referent', 'referent_table')
])
def batch_create_foreign_key(
cls, operations, constraint_name, referent_table,
local_cols, remote_cols,
referent_schema=None,
onupdate=None, ondelete=None,
deferrable=None, initially=None, match=None,
**dialect_kw):
"""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`
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* referent -> referent_table
"""
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")
class CreateCheckConstraintOp(AddConstraintOp):
"""Represent a create check constraint operation."""
constraint_type = "check"
def __init__(
self, constraint_name, table_name,
condition, schema=None, _orig_constraint=None, **kw):
self.constraint_name = constraint_name
self.table_name = table_name
self.condition = condition
self.schema = schema
self._orig_constraint = _orig_constraint
self.kw = kw
@classmethod
def from_constraint(cls, constraint):
constraint_table = sqla_compat._table_for_constraint(constraint)
return cls(
constraint.name,
constraint_table.name,
constraint.sqltext,
schema=constraint_table.schema,
_orig_constraint=constraint
)
def to_constraint(self, migration_context=None):
if self._orig_constraint is not None:
return self._orig_constraint
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
@util._with_legacy_names([
('name', 'constraint_name'),
('source', 'table_name')
])
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
@classmethod
@util._with_legacy_names([('name', 'constraint_name')])
def batch_create_check_constraint(
cls, operations, constraint_name, condition, **kw):
"""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`
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
"""
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, table_name, columns, schema=None,
unique=False, _orig_index=None, **kw):
self.index_name = index_name
self.table_name = table_name
self.columns = columns
self.schema = schema
self.unique = unique
self.kw = kw
self._orig_index = _orig_index
def reverse(self):
return DropIndexOp.from_index(self.to_index())
def to_diff_tuple(self):
return ("add_index", self.to_index())
@classmethod
def from_index(cls, index):
return cls(
index.name,
index.table.name,
sqla_compat._get_index_expressions(index),
schema=index.table.schema,
unique=index.unique,
_orig_index=index,
**index.kwargs
)
def to_index(self, migration_context=None):
if self._orig_index:
return self._orig_index
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.index(
self.index_name, self.table_name, self.columns, schema=self.schema,
unique=self.unique, **self.kw)
@classmethod
@util._with_legacy_names([('name', 'index_name')])
def create_index(
cls, operations,
index_name, table_name, columns, schema=None,
unique=False, **kw):
"""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)')])
.. versionadded:: 0.6.7 support for making use of the
:func:`~sqlalchemy.sql.expression.text` construct in
conjunction with
:meth:`.Operations.create_index` in
order to produce functional expressions within CREATE INDEX.
: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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
: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.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> index_name
"""
op = cls(
index_name, table_name, columns, schema=schema,
unique=unique, **kw
)
return operations.invoke(op)
@classmethod
def batch_create_index(cls, operations, index_name, columns, **kw):
"""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, table_name=None, schema=None, _orig_index=None):
self.index_name = index_name
self.table_name = table_name
self.schema = schema
self._orig_index = _orig_index
def to_diff_tuple(self):
return ("remove_index", self.to_index())
def reverse(self):
if self._orig_index is None:
raise ValueError(
"operation is not reversible; "
"original index is not present")
return CreateIndexOp.from_index(self._orig_index)
@classmethod
def from_index(cls, index):
return cls(
index.name,
index.table.name,
schema=index.table.schema,
_orig_index=index
)
def to_index(self, migration_context=None):
if self._orig_index is not None:
return self._orig_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, ['x'], schema=self.schema)
@classmethod
@util._with_legacy_names([
('name', 'index_name'),
('tablename', 'table_name')
])
def drop_index(cls, operations, index_name, table_name=None, schema=None):
"""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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> index_name
"""
op = cls(index_name, table_name=table_name, schema=schema)
return operations.invoke(op)
@classmethod
@util._with_legacy_names([('name', 'index_name')])
def batch_drop_index(cls, operations, index_name, **kw):
"""Issue a "drop index" instruction using the
current batch migration context.
.. seealso::
:meth:`.Operations.drop_index`
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> index_name
"""
op = cls(
index_name, table_name=operations.impl.table_name,
schema=operations.impl.schema
)
return operations.invoke(op)
@Operations.register_operation("create_table")
class CreateTableOp(MigrateOperation):
"""Represent a create table operation."""
def __init__(
self, table_name, columns, schema=None, _orig_table=None, **kw):
self.table_name = table_name
self.columns = columns
self.schema = schema
self.kw = kw
self._orig_table = _orig_table
def reverse(self):
return DropTableOp.from_table(self.to_table())
def to_diff_tuple(self):
return ("add_table", self.to_table())
@classmethod
def from_table(cls, table):
return cls(
table.name,
list(table.c) + list(table.constraints),
schema=table.schema,
_orig_table=table,
**table.kwargs
)
def to_table(self, migration_context=None):
if self._orig_table is not None:
return self._orig_table
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.table(
self.table_name, *self.columns, schema=self.schema, **self.kw
)
@classmethod
@util._with_legacy_names([('name', 'table_name')])
def create_table(cls, operations, table_name, *columns, **kw):
"""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"},
]
)
.. versionadded:: 0.7.0
: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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
: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.
.. versionadded:: 0.7.0 - the :class:`~sqlalchemy.schema.Table`
object is returned.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> table_name
"""
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, schema=None, table_kw=None, _orig_table=None):
self.table_name = table_name
self.schema = schema
self.table_kw = table_kw or {}
self._orig_table = _orig_table
def to_diff_tuple(self):
return ("remove_table", self.to_table())
def reverse(self):
if self._orig_table is None:
raise ValueError(
"operation is not reversible; "
"original table is not present")
return CreateTableOp.from_table(self._orig_table)
@classmethod
def from_table(cls, table):
return cls(table.name, schema=table.schema, _orig_table=table)
def to_table(self, migration_context=None):
if self._orig_table is not None:
return self._orig_table
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.table(
self.table_name,
schema=self.schema,
**self.table_kw)
@classmethod
@util._with_legacy_names([('name', 'table_name')])
def drop_table(cls, operations, table_name, schema=None, **kw):
"""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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
:param \**kw: Other keyword arguments are passed to the underlying
:class:`sqlalchemy.schema.Table` object created for the command.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> table_name
"""
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, schema=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, new_table_name, schema=None):
super(RenameTableOp, self).__init__(old_table_name, schema=schema)
self.new_table_name = new_table_name
@classmethod
def rename_table(
cls, operations, old_table_name, new_table_name, schema=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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
"""
op = cls(old_table_name, new_table_name, schema=schema)
return operations.invoke(op)
@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, column_name, schema=None,
existing_type=None,
existing_server_default=False,
existing_nullable=None,
modify_nullable=None,
modify_server_default=False,
modify_name=None,
modify_type=None,
**kw
):
super(AlterColumnOp, self).__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.modify_nullable = modify_nullable
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):
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,
},
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
},
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
},
self.existing_server_default,
self.modify_server_default)
)
return col_diff
def has_changes(self):
hc1 = self.modify_nullable is not None or \
self.modify_server_default is not False or \
self.modify_type is not None
if hc1:
return True
for kw in self.kw:
if kw.startswith('modify_'):
return True
else:
return False
def reverse(self):
kw = self.kw.copy()
kw['existing_type'] = self.existing_type
kw['existing_nullable'] = self.existing_nullable
kw['existing_server_default'] = self.existing_server_default
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
# TODO: make this a little simpler
all_keys = set(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
@util._with_legacy_names([('name', 'new_column_name')])
def alter_column(
cls, operations, table_name, column_name,
nullable=None,
server_default=False,
new_column_name=None,
type_=None,
existing_type=None,
existing_server_default=False,
existing_nullable=None,
schema=None, **kw
):
"""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_server_default`` argument is
used in this case as well to remove a previous
constraint.
: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 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 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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
"""
alt = cls(
table_name, column_name, schema=schema,
existing_type=existing_type,
existing_server_default=existing_server_default,
existing_nullable=existing_nullable,
modify_name=new_column_name,
modify_type=type_,
modify_server_default=server_default,
modify_nullable=nullable,
**kw
)
return operations.invoke(alt)
@classmethod
def batch_alter_column(
cls, operations, column_name,
nullable=None,
server_default=False,
new_column_name=None,
type_=None,
existing_type=None,
existing_server_default=False,
existing_nullable=None,
**kw
):
"""Issue an "alter column" instruction using the current
batch migration context.
.. seealso::
:meth:`.Operations.add_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,
modify_name=new_column_name,
modify_type=type_,
modify_server_default=server_default,
modify_nullable=nullable,
**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, column, schema=None):
super(AddColumnOp, self).__init__(table_name, schema=schema)
self.column = column
def reverse(self):
return DropColumnOp.from_column_and_tablename(
self.schema, self.table_name, self.column)
def to_diff_tuple(self):
return ("add_column", self.schema, self.table_name, self.column)
def to_column(self):
return self.column
@classmethod
def from_column(cls, col):
return cls(col.table.name, col, schema=col.table.schema)
@classmethod
def from_column_and_tablename(cls, schema, tname, col):
return cls(tname, col, schema=schema)
@classmethod
def add_column(cls, operations, table_name, column, schema=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 provided :class:`~sqlalchemy.schema.Column` object can also
specify a :class:`~sqlalchemy.schema.ForeignKey`, referencing
a remote table name. Alembic will automatically generate a stub
"referenced" table and emit a second ALTER statement in order
to add the constraint separately::
from alembic import op
from sqlalchemy import Column, INTEGER, ForeignKey
op.add_column('organization',
Column('account_id', INTEGER, ForeignKey('accounts.id'))
)
Note that this statement uses the :class:`~sqlalchemy.schema.Column`
construct as is 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 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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
"""
op = cls(table_name, column, schema=schema)
return operations.invoke(op)
@classmethod
def batch_add_column(cls, operations, column):
"""Issue an "add column" instruction using the current
batch migration context.
.. seealso::
:meth:`.Operations.add_column`
"""
op = cls(
operations.impl.table_name, column,
schema=operations.impl.schema
)
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, column_name, schema=None,
_orig_column=None, **kw):
super(DropColumnOp, self).__init__(table_name, schema=schema)
self.column_name = column_name
self.kw = kw
self._orig_column = _orig_column
def to_diff_tuple(self):
return (
"remove_column", self.schema, self.table_name, self.to_column())
def reverse(self):
if self._orig_column 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._orig_column)
@classmethod
def from_column_and_tablename(cls, schema, tname, col):
return cls(tname, col.name, schema=schema, _orig_column=col)
def to_column(self, migration_context=None):
if self._orig_column is not None:
return self._orig_column
schema_obj = schemaobj.SchemaObjects(migration_context)
return schema_obj.column(self.column_name, NULLTYPE)
@classmethod
def drop_column(
cls, operations, table_name, column_name, schema=None, **kw):
"""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`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
: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.
.. versionadded:: 0.6.2
"""
op = cls(table_name, column_name, schema=schema, **kw)
return operations.invoke(op)
@classmethod
def batch_drop_column(cls, operations, column_name):
"""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)
return operations.invoke(op)
@Operations.register_operation("bulk_insert")
class BulkInsertOp(MigrateOperation):
"""Represent a bulk insert operation."""
def __init__(self, table, rows, multiinsert=True):
self.table = table
self.rows = rows
self.multiinsert = multiinsert
@classmethod
def bulk_insert(cls, operations, table, rows, multiinsert=True):
"""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.
.. versionadded:: 0.6.4 :meth:`.Operations.inline_literal` can now
be used with :meth:`.Operations.bulk_insert`, and the
:paramref:`~.Operations.bulk_insert.multiinsert` flag has
been added to assist in this usage when running in "online"
mode.
: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.
.. versionadded:: 0.6.4
"""
op = cls(table, rows, multiinsert=multiinsert)
operations.invoke(op)
@Operations.register_operation("execute")
class ExecuteSQLOp(MigrateOperation):
"""Represent an execute SQL operation."""
def __init__(self, sqltext, execution_options=None):
self.sqltext = sqltext
self.execution_options = execution_options
@classmethod
def execute(cls, operations, sqltext, execution_options=None):
"""Execute the given SQL using the current migration context.
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. For full interaction
with a connected database, use the "bind" available
from the context::
from alembic import op
connection = op.get_bind()
Also note that any parameterized statement here *will not work*
in offline mode - INSERT, UPDATE and DELETE statements which refer
to literal values would need to render
inline expressions. For simple use cases, the
:meth:`.inline_literal` function can be used for **rudimentary**
quoting of string values. For "bulk" inserts, consider using
:meth:`.bulk_insert`.
For example, to emit an UPDATE statement which is equally
compatible with both online and offline mode::
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')})
)
Note above we also used 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.
:param sql: 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.
* Pretty much anything that's "executable" as described
in :ref:`sqlexpression_toplevel`.
: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)
class OpContainer(MigrateOperation):
"""Represent a sequence of operations operation."""
def __init__(self, ops=()):
self.ops = ops
def is_empty(self):
return not self.ops
def as_diffs(self):
return list(OpContainer._ops_as_diffs(self))
@classmethod
def _ops_as_diffs(cls, migrations):
for op in migrations.ops:
if hasattr(op, 'ops'):
for sub_op in cls._ops_as_diffs(op):
yield sub_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, ops, schema=None):
super(ModifyTableOps, self).__init__(ops)
self.table_name = table_name
self.schema = schema
def reverse(self):
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=(), upgrade_token="upgrades"):
super(UpgradeOps, self).__init__(ops=ops)
self.upgrade_token = upgrade_token
def reverse_into(self, downgrade_ops):
downgrade_ops.ops[:] = list(reversed(
[op.reverse() for op in self.ops]
))
return downgrade_ops
def reverse(self):
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=(), downgrade_token="downgrades"):
super(DowngradeOps, self).__init__(ops=ops)
self.downgrade_token = downgrade_token
def reverse(self):
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.
.. versionchanged:: 0.8.1 the ``.upgrade_ops`` and ``.downgrade_ops``
attributes should be accessed via the ``.upgrade_ops_list``
and ``.downgrade_ops_list`` attributes if multiple autogenerate
passes proceed on the same :class:`.MigrationScript` object.
.. seealso::
:ref:`customizing_revision`
"""
def __init__(
self, rev_id, upgrade_ops, downgrade_ops,
message=None,
imports=set(), head=None, splice=None,
branch_label=None, version_path=None, depends_on=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):
"""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):
self._upgrade_ops = util.to_list(upgrade_ops)
for elem in self._upgrade_ops:
assert isinstance(elem, UpgradeOps)
@property
def downgrade_ops(self):
"""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):
self._downgrade_ops = util.to_list(downgrade_ops)
for elem in self._downgrade_ops:
assert isinstance(elem, DowngradeOps)
@property
def upgrade_ops_list(self):
"""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.
.. versionadded:: 0.8.1
"""
return self._upgrade_ops
@property
def downgrade_ops_list(self):
"""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.
.. versionadded:: 0.8.1
"""
return self._downgrade_ops
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