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Edit File: ops.py
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 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 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 sqlalchemy.sql.dml import Insert from sqlalchemy.sql.dml import Update from sqlalchemy.sql.elements import BinaryExpression 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 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): """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): raise NotImplementedError() @classmethod def register_add_constraint(cls, type_: str) -> Callable: def go(klass): 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__)( 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[str], 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( constraint.name, constraint_table.name, schema=constraint_table.schema, type_=types[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, ) -> Optional["Table"]: 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[str], table_name: str, columns: Sequence[str], schema: Optional[str] = None, **kw, ) -> 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( 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, ) -> Optional["Table"]: """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) return operations.invoke(op) @classmethod def batch_create_primary_key( cls, operations: "BatchOperations", constraint_name: 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[str], table_name: str, columns: Sequence[str], schema: Optional[str] = None, **kw, ) -> 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 = {} 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( 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: """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: """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[str], source_table: str, referent_table: str, local_cols: List[str], remote_cols: List[str], **kw, ) -> 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 = {} 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 ( 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( 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, ) -> Optional["Table"]: """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: str, referent_table: str, local_cols: List[str], remote_cols: List[str], referent_schema: Optional[str] = None, onupdate: None = None, ondelete: None = None, deferrable: None = None, initially: None = None, match: None = None, **dialect_kw, ) -> 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[str], table_name: str, condition: Union[str, "TextClause", "ColumnElement[Any]"], schema: Optional[str] = None, **kw, ) -> 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( 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, "BinaryExpression"], schema: Optional[str] = None, **kw, ) -> Optional["Table"]: """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: "TextClause", **kw, ) -> Optional["Table"]: """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: str, table_name: str, columns: Sequence[Union[str, "TextClause", "ColumnElement[Any]"]], schema: Optional[str] = None, unique: bool = False, **kw, ) -> None: self.index_name = index_name self.table_name = table_name self.columns = columns self.schema = schema self.unique = unique 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, sqla_compat._get_index_expressions(index), 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: str, table_name: str, columns: Sequence[Union[str, "TextClause", "Function"]], schema: Optional[str] = None, unique: bool = False, **kw, ) -> Optional["Table"]: r"""Issue a "create index" instruction using the current migration context. e.g.:: from alembic import op op.create_index('ik_test', 't1', ['foo', 'bar']) Functional indexes can be produced by using the :func:`sqlalchemy.sql.expression.text` construct:: from alembic import op from sqlalchemy import text op.create_index('ik_test', 't1', [text('lower(foo)')]) :param index_name: name of the index. :param table_name: name of the owning table. :param columns: a list consisting of string column names and/or :func:`~sqlalchemy.sql.expression.text` constructs. :param schema: Optional schema name to operate within. To control quoting of the schema outside of the default behavior, use the SQLAlchemy construct :class:`~sqlalchemy.sql.elements.quoted_name`. :param unique: If True, create a unique index. :param quote: Force quoting of this column's name on or off, corresponding to ``True`` or ``False``. When left at its default of ``None``, the column identifier will be quoted according to whether the name is case sensitive (identifiers with at least one upper case character are treated as case sensitive), or if it's a reserved word. This flag is only needed to force quoting of a reserved word which is not known by the SQLAlchemy dialect. :param \**kw: Additional keyword arguments not mentioned above are dialect specific, and passed in the form ``<dialectname>_<argname>``. See the documentation regarding an individual dialect at :ref:`dialect_toplevel` for detail on documented arguments. """ op = cls( index_name, table_name, columns, schema=schema, unique=unique, **kw ) return operations.invoke(op) @classmethod def batch_create_index( cls, operations: "BatchOperations", index_name: str, columns: List[str], **kw, ) -> Optional["Table"]: """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, _reverse: Optional["CreateIndexOp"] = None, **kw, ) -> None: self.index_name = index_name self.table_name = table_name self.schema = schema 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, index.table.name, schema=index.table.schema, _reverse=CreateIndexOp.from_index(index), **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, **kw, ) -> Optional["Table"]: r"""Issue a "drop index" instruction using the current migration context. e.g.:: drop_index("accounts") :param index_name: name of the index. :param table_name: name of the owning table. Some backends such as Microsoft SQL Server require this. :param schema: Optional schema name to operate within. To control quoting of the schema outside of the default behavior, use the SQLAlchemy construct :class:`~sqlalchemy.sql.elements.quoted_name`. :param \**kw: Additional keyword arguments not mentioned above are dialect specific, and passed in the form ``<dialectname>_<argname>``. See the documentation regarding an individual dialect at :ref:`dialect_toplevel` for detail on documented arguments. """ op = cls(index_name, table_name=table_name, schema=schema, **kw) return operations.invoke(op) @classmethod def batch_drop_index( cls, operations: BatchOperations, index_name: str, **kw ) -> Optional["Table"]: """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[Union["Column", "Constraint"]], schema: Optional[str] = None, _namespace_metadata: Optional["MetaData"] = None, _constraints_included: bool = False, **kw, ) -> 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), # type:ignore[arg-type] 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, **kw ) -> Optional["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(RenameTableOp, self).__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, ) -> Optional["Table"]: """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: None = None, schema: Optional[str] = None, ) -> Optional["Table"]: """Emit a COMMENT ON operation to set the comment for a table. .. versionadded:: 1.0.6 :param table_name: string name of the target table. :param comment: string value of the comment being registered against the specified table. :param existing_comment: String value of a comment already registered on the specified table, used within autogenerate so that the operation is reversible, but not required for direct use. .. seealso:: :meth:`.Operations.drop_table_comment` :paramref:`.Operations.alter_column.comment` """ op = cls( table_name, comment, existing_comment=existing_comment, schema=schema, ) return operations.invoke(op) @classmethod def batch_create_table_comment( cls, operations, comment, existing_comment=None, ): """Emit a COMMENT ON operation to set the comment for a table using the current batch migration context. .. versionadded:: 1.6.0 :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): """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=None): schema_obj = schemaobj.SchemaObjects(migration_context) return schema_obj.table( self.table_name, schema=self.schema, comment=self.comment ) def to_diff_tuple(self): 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, ) -> Optional["Table"]: """Issue a "drop table comment" operation to remove an existing comment set on a table. .. versionadded:: 1.0.6 :param table_name: string name of the target table. :param existing_comment: An optional string value of a comment already registered on the specified table. .. seealso:: :meth:`.Operations.create_table_comment` :paramref:`.Operations.alter_column.comment` """ op = cls(table_name, existing_comment=existing_comment, schema=schema) return operations.invoke(op) @classmethod def batch_drop_table_comment(cls, operations, existing_comment=None): """Issue a "drop table comment" operation to remove an existing comment set on a table using the current batch operations context. .. versionadded:: 1.6.0 :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): """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=None): schema_obj = schemaobj.SchemaObjects(migration_context) return schema_obj.table(self.table_name, schema=self.schema) def to_diff_tuple(self): 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, bool]] = False, modify_server_default: Any = False, modify_name: Optional[str] = None, modify_type: Optional[Any] = None, **kw, ) -> None: 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.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 = 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 def alter_column( cls, operations: Operations, table_name: str, column_name: str, nullable: Optional[bool] = None, comment: Optional[Union[str, bool]] = False, server_default: Any = False, new_column_name: Optional[str] = None, type_: Optional[Union["TypeEngine", Type["TypeEngine"]]] = None, existing_type: Optional[ Union["TypeEngine", Type["TypeEngine"]] ] = 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, ) -> Optional["Table"]: r"""Issue an "alter column" instruction using the current migration context. Generally, only that aspect of the column which is being changed, i.e. name, type, nullability, default, needs to be specified. Multiple changes can also be specified at once and the backend should "do the right thing", emitting each change either separately or together as the backend allows. MySQL has special requirements here, since MySQL cannot ALTER a column without a full specification. When producing MySQL-compatible migration files, it is recommended that the ``existing_type``, ``existing_server_default``, and ``existing_nullable`` parameters be present, if not being altered. Type changes which are against the SQLAlchemy "schema" types :class:`~sqlalchemy.types.Boolean` and :class:`~sqlalchemy.types.Enum` may also add or drop constraints which accompany those types on backends that don't support them natively. The ``existing_type`` argument is used in this case to identify and remove a previous constraint that was bound to the type object. :param table_name: string name of the target table. :param column_name: string name of the target column, as it exists before the operation begins. :param nullable: Optional; specify ``True`` or ``False`` to alter the column's nullability. :param server_default: Optional; specify a string SQL expression, :func:`~sqlalchemy.sql.expression.text`, or :class:`~sqlalchemy.schema.DefaultClause` to indicate an alteration to the column's default value. Set to ``None`` to have the default removed. :param comment: optional string text of a new comment to add to the column. .. versionadded:: 1.0.6 :param new_column_name: Optional; specify a string name here to indicate the new name within a column rename operation. :param type\_: Optional; a :class:`~sqlalchemy.types.TypeEngine` type object to specify a change to the column's type. For SQLAlchemy types that also indicate a constraint (i.e. :class:`~sqlalchemy.types.Boolean`, :class:`~sqlalchemy.types.Enum`), the constraint is also generated. :param autoincrement: set the ``AUTO_INCREMENT`` flag of the column; currently understood by the MySQL dialect. :param existing_type: Optional; a :class:`~sqlalchemy.types.TypeEngine` type object to specify the previous type. This is required for all MySQL column alter operations that don't otherwise specify a new type, as well as for when nullability is being changed on a SQL Server column. It is also used if the type is a so-called SQLlchemy "schema" type which may define a constraint (i.e. :class:`~sqlalchemy.types.Boolean`, :class:`~sqlalchemy.types.Enum`), so that the constraint can be dropped. :param existing_server_default: Optional; The existing default value of the column. Required on MySQL if an existing default is not being changed; else MySQL removes the default. :param existing_nullable: Optional; the existing nullability of the column. Required on MySQL if the existing nullability is not being changed; else MySQL sets this to NULL. :param existing_autoincrement: Optional; the existing autoincrement of the column. Used for MySQL's system of altering a column that specifies ``AUTO_INCREMENT``. :param existing_comment: string text of the existing comment on the column to be maintained. Required on MySQL if the existing comment on the column is not being changed. .. versionadded:: 1.0.6 :param schema: Optional schema name to operate within. To control quoting of the schema outside of the default behavior, use the SQLAlchemy construct :class:`~sqlalchemy.sql.elements.quoted_name`. :param postgresql_using: String argument which will indicate a SQL expression to render within the Postgresql-specific USING clause within ALTER COLUMN. This string is taken directly as raw SQL which must explicitly include any necessary quoting or escaping of tokens within the expression. """ 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: bool = False, server_default: Union["Function", bool] = False, new_column_name: Optional[str] = None, type_: Optional[Union["TypeEngine", Type["TypeEngine"]]] = None, existing_type: Optional[ Union["TypeEngine", Type["TypeEngine"]] ] = None, existing_server_default: bool = False, existing_nullable: None = None, existing_comment: None = None, insert_before: None = None, insert_after: None = None, **kw, ) -> Optional["Table"]: """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. .. versionadded:: 1.4.0 :param insert_before: 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. .. versionadded:: 1.4.0 .. 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, **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", schema: Optional[str] = None, **kw, ) -> None: super(AddColumnOp, self).__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"]: return ("add_column", self.schema, self.table_name, self.column) def to_column(self) -> "Column": return self.column @classmethod def from_column(cls, col: "Column") -> "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", ) -> "AddColumnOp": return cls(tname, col, schema=schema) @classmethod def add_column( cls, operations: "Operations", table_name: str, column: "Column", schema: Optional[str] = None, ) -> Optional["Table"]: """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`. """ op = cls(table_name, column, schema=schema) return operations.invoke(op) @classmethod def batch_add_column( cls, operations: "BatchOperations", column: "Column", insert_before: Optional[str] = None, insert_after: Optional[str] = None, ) -> Optional["Table"]: """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, ) -> None: super(DropColumnOp, self).__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"]: 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", ) -> "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": 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, ) -> Optional["Table"]: """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 ) -> Optional["Table"]: """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], 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], 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") class ExecuteSQLOp(MigrateOperation): """Represent an execute SQL operation.""" def __init__( self, sqltext: Union["Update", str, "Insert", "TextClause"], execution_options: None = None, ) -> None: self.sqltext = sqltext self.execution_options = execution_options @classmethod def execute( cls, operations: Operations, sqltext: Union[str, "TextClause", "Update"], execution_options: None = None, ) -> Optional["Table"]: r"""Execute the given SQL using the current migration context. The given SQL can be a plain string, e.g.:: op.execute("INSERT INTO table (foo) VALUES ('some value')") Or it can be any kind of Core SQL Expression construct, such as below where we use an update construct:: from sqlalchemy.sql import table, column from sqlalchemy import String from alembic import op account = table('account', column('name', String) ) op.execute( account.update().\\ where(account.c.name==op.inline_literal('account 1')).\\ values({'name':op.inline_literal('account 2')}) ) Above, we made use of the SQLAlchemy :func:`sqlalchemy.sql.expression.table` and :func:`sqlalchemy.sql.expression.column` constructs to make a brief, ad-hoc table construct just for our UPDATE statement. A full :class:`~sqlalchemy.schema.Table` construct of course works perfectly fine as well, though note it's a recommended practice to at least ensure the definition of a table is self-contained within the migration script, rather than imported from a module that may break compatibility with older migrations. In a SQL script context, the statement is emitted directly to the output stream. There is *no* return result, however, as this function is oriented towards generating a change script that can run in "offline" mode. Additionally, parameterized statements are discouraged here, as they *will not work* in offline mode. Above, we use :meth:`.inline_literal` where parameters are to be used. For full interaction with a connected database where parameters can also be used normally, use the "bind" available from the context:: from alembic import op connection = op.get_bind() connection.execute( account.update().where(account.c.name=='account 1'). values({"name": "account 2"}) ) Additionally, when passing the statement as a plain string, it is first coerceed into a :func:`sqlalchemy.sql.expression.text` construct before being passed along. In the less likely case that the literal SQL string contains a colon, it must be escaped with a backslash, as:: op.execute("INSERT INTO table (foo) VALUES ('\:colon_value')") :param sqltext: Any legal SQLAlchemy expression, including: * a string * a :func:`sqlalchemy.sql.expression.text` construct. * a :func:`sqlalchemy.sql.expression.insert` construct. * a :func:`sqlalchemy.sql.expression.update`, :func:`sqlalchemy.sql.expression.insert`, or :func:`sqlalchemy.sql.expression.delete` construct. * Pretty much anything that's "executable" as described in :ref:`sqlexpression_toplevel`. .. 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) 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"): for sub_op in cls._ops_as_diffs(cast("OpContainer", 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: str, ops: Sequence[MigrateOperation], schema: Optional[str] = None, ) -> None: super(ModifyTableOps, self).__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(UpgradeOps, self).__init__(ops=ops) self.upgrade_token = upgrade_token def reverse_into(self, downgrade_ops: "DowngradeOps") -> "DowngradeOps": downgrade_ops.ops[:] = list( # type:ignore[index] 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(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. .. seealso:: :ref:`customizing_revision` """ _needs_render: Optional[bool] 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[str] = None, version_path: Optional[str] = None, depends_on: Optional[Union[str, Sequence[str]]] = 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): """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) -> 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