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