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from __future__ import annotations
import re
from typing import Any
from typing import List
from typing import Optional
from typing import TYPE_CHECKING
from typing import Union
from sqlalchemy import types as sqltypes
from sqlalchemy.ext.compiler import compiles
from sqlalchemy.schema import Column
from sqlalchemy.schema import CreateIndex
from sqlalchemy.sql.base import Executable
from sqlalchemy.sql.elements import ClauseElement
from .base import AddColumn
from .base import alter_column
from .base import alter_table
from .base import ColumnDefault
from .base import ColumnName
from .base import ColumnNullable
from .base import ColumnType
from .base import format_column_name
from .base import format_server_default
from .base import format_table_name
from .base import format_type
from .base import RenameTable
from .impl import DefaultImpl
from .. import util
from ..util import sqla_compat
if TYPE_CHECKING:
from typing import Literal
from sqlalchemy.dialects.mssql.base import MSDDLCompiler
from sqlalchemy.dialects.mssql.base import MSSQLCompiler
from sqlalchemy.engine.cursor import CursorResult
from sqlalchemy.sql.schema import Index
from sqlalchemy.sql.schema import Table
from sqlalchemy.sql.selectable import TableClause
from sqlalchemy.sql.type_api import TypeEngine
from .base import _ServerDefault
class MSSQLImpl(DefaultImpl):
__dialect__ = "mssql"
transactional_ddl = True
batch_separator = "GO"
type_synonyms = DefaultImpl.type_synonyms + ({"VARCHAR", "NVARCHAR"},)
identity_attrs_ignore = (
"minvalue",
"maxvalue",
"nominvalue",
"nomaxvalue",
"cycle",
"cache",
"order",
"on_null",
"order",
)
def __init__(self, *arg, **kw) -> None:
super().__init__(*arg, **kw)
self.batch_separator = self.context_opts.get(
"mssql_batch_separator", self.batch_separator
)
def _exec(self, construct: Any, *args, **kw) -> Optional[CursorResult]:
result = super()._exec(construct, *args, **kw)
if self.as_sql and self.batch_separator:
self.static_output(self.batch_separator)
return result
def emit_begin(self) -> None:
self.static_output("BEGIN TRANSACTION" + self.command_terminator)
def emit_commit(self) -> None:
super().emit_commit()
if self.as_sql and self.batch_separator:
self.static_output(self.batch_separator)
def alter_column( # type:ignore[override]
self,
table_name: str,
column_name: str,
nullable: Optional[bool] = None,
server_default: Optional[
Union[_ServerDefault, Literal[False]]
] = False,
name: Optional[str] = None,
type_: Optional[TypeEngine] = None,
schema: Optional[str] = None,
existing_type: Optional[TypeEngine] = None,
existing_server_default: Optional[_ServerDefault] = None,
existing_nullable: Optional[bool] = None,
**kw: Any,
) -> None:
if nullable is not None:
if type_ is not None:
# the NULL/NOT NULL alter will handle
# the type alteration
existing_type = type_
type_ = None
elif existing_type is None:
raise util.CommandError(
"MS-SQL ALTER COLUMN operations "
"with NULL or NOT NULL require the "
"existing_type or a new type_ be passed."
)
elif existing_nullable is not None and type_ is not None:
nullable = existing_nullable
# the NULL/NOT NULL alter will handle
# the type alteration
existing_type = type_
type_ = None
elif type_ is not None:
util.warn(
"MS-SQL ALTER COLUMN operations that specify type_= "
"should also specify a nullable= or "
"existing_nullable= argument to avoid implicit conversion "
"of NOT NULL columns to NULL."
)
used_default = False
if sqla_compat._server_default_is_identity(
server_default, existing_server_default
) or sqla_compat._server_default_is_computed(
server_default, existing_server_default
):
used_default = True
kw["server_default"] = server_default
kw["existing_server_default"] = existing_server_default
super().alter_column(
table_name,
column_name,
nullable=nullable,
type_=type_,
schema=schema,
existing_type=existing_type,
existing_nullable=existing_nullable,
**kw,
)
if server_default is not False and used_default is False:
if existing_server_default is not False or server_default is None:
self._exec(
_ExecDropConstraint(
table_name,
column_name,
"sys.default_constraints",
schema,
)
)
if server_default is not None:
super().alter_column(
table_name,
column_name,
schema=schema,
server_default=server_default,
)
if name is not None:
super().alter_column(
table_name, column_name, schema=schema, name=name
)
def create_index(self, index: Index) -> None:
# this likely defaults to None if not present, so get()
# should normally not return the default value. being
# defensive in any case
mssql_include = index.kwargs.get("mssql_include", None) or ()
assert index.table is not None
for col in mssql_include:
if col not in index.table.c:
index.table.append_column(Column(col, sqltypes.NullType))
self._exec(CreateIndex(index))
def bulk_insert( # type:ignore[override]
self, table: Union[TableClause, Table], rows: List[dict], **kw: Any
) -> None:
if self.as_sql:
self._exec(
"SET IDENTITY_INSERT %s ON"
% self.dialect.identifier_preparer.format_table(table)
)
super().bulk_insert(table, rows, **kw)
self._exec(
"SET IDENTITY_INSERT %s OFF"
% self.dialect.identifier_preparer.format_table(table)
)
else:
super().bulk_insert(table, rows, **kw)
def drop_column(
self,
table_name: str,
column: Column[Any],
schema: Optional[str] = None,
**kw,
) -> None:
drop_default = kw.pop("mssql_drop_default", False)
if drop_default:
self._exec(
_ExecDropConstraint(
table_name, column, "sys.default_constraints", schema
)
)
drop_check = kw.pop("mssql_drop_check", False)
if drop_check:
self._exec(
_ExecDropConstraint(
table_name, column, "sys.check_constraints", schema
)
)
drop_fks = kw.pop("mssql_drop_foreign_key", False)
if drop_fks:
self._exec(_ExecDropFKConstraint(table_name, column, schema))
super().drop_column(table_name, column, schema=schema, **kw)
def compare_server_default(
self,
inspector_column,
metadata_column,
rendered_metadata_default,
rendered_inspector_default,
):
if rendered_metadata_default is not None:
rendered_metadata_default = re.sub(
r"[\(\) \"\']", "", rendered_metadata_default
)
if rendered_inspector_default is not None:
# SQL Server collapses whitespace and adds arbitrary parenthesis
# within expressions. our only option is collapse all of it
rendered_inspector_default = re.sub(
r"[\(\) \"\']", "", rendered_inspector_default
)
return rendered_inspector_default != rendered_metadata_default
def _compare_identity_default(self, metadata_identity, inspector_identity):
diff, ignored, is_alter = super()._compare_identity_default(
metadata_identity, inspector_identity
)
if (
metadata_identity is None
and inspector_identity is not None
and not diff
and inspector_identity.column is not None
and inspector_identity.column.primary_key
):
# mssql reflect primary keys with autoincrement as identity
# columns. if no different attributes are present ignore them
is_alter = False
return diff, ignored, is_alter
class _ExecDropConstraint(Executable, ClauseElement):
inherit_cache = False
def __init__(
self,
tname: str,
colname: Union[Column[Any], str],
type_: str,
schema: Optional[str],
) -> None:
self.tname = tname
self.colname = colname
self.type_ = type_
self.schema = schema
class _ExecDropFKConstraint(Executable, ClauseElement):
inherit_cache = False
def __init__(
self, tname: str, colname: Column[Any], schema: Optional[str]
) -> None:
self.tname = tname
self.colname = colname
self.schema = schema
@compiles(_ExecDropConstraint, "mssql")
def _exec_drop_col_constraint(
element: _ExecDropConstraint, compiler: MSSQLCompiler, **kw
) -> str:
schema, tname, colname, type_ = (
element.schema,
element.tname,
element.colname,
element.type_,
)
# from http://www.mssqltips.com/sqlservertip/1425/\
# working-with-default-constraints-in-sql-server/
return """declare @const_name varchar(256)
select @const_name = QUOTENAME([name]) from %(type)s
where parent_object_id = object_id('%(schema_dot)s%(tname)s')
and col_name(parent_object_id, parent_column_id) = '%(colname)s'
exec('alter table %(tname_quoted)s drop constraint ' + @const_name)""" % {
"type": type_,
"tname": tname,
"colname": colname,
"tname_quoted": format_table_name(compiler, tname, schema),
"schema_dot": schema + "." if schema else "",
}
@compiles(_ExecDropFKConstraint, "mssql")
def _exec_drop_col_fk_constraint(
element: _ExecDropFKConstraint, compiler: MSSQLCompiler, **kw
) -> str:
schema, tname, colname = element.schema, element.tname, element.colname
return """declare @const_name varchar(256)
select @const_name = QUOTENAME([name]) from
sys.foreign_keys fk join sys.foreign_key_columns fkc
on fk.object_id=fkc.constraint_object_id
where fkc.parent_object_id = object_id('%(schema_dot)s%(tname)s')
and col_name(fkc.parent_object_id, fkc.parent_column_id) = '%(colname)s'
exec('alter table %(tname_quoted)s drop constraint ' + @const_name)""" % {
"tname": tname,
"colname": colname,
"tname_quoted": format_table_name(compiler, tname, schema),
"schema_dot": schema + "." if schema else "",
}
@compiles(AddColumn, "mssql")
def visit_add_column(element: AddColumn, compiler: MSDDLCompiler, **kw) -> str:
return "%s %s" % (
alter_table(compiler, element.table_name, element.schema),
mssql_add_column(compiler, element.column, **kw),
)
def mssql_add_column(
compiler: MSDDLCompiler, column: Column[Any], **kw
) -> str:
return "ADD %s" % compiler.get_column_specification(column, **kw)
@compiles(ColumnNullable, "mssql")
def visit_column_nullable(
element: ColumnNullable, compiler: MSDDLCompiler, **kw
) -> str:
return "%s %s %s %s" % (
alter_table(compiler, element.table_name, element.schema),
alter_column(compiler, element.column_name),
format_type(compiler, element.existing_type), # type: ignore[arg-type]
"NULL" if element.nullable else "NOT NULL",
)
@compiles(ColumnDefault, "mssql")
def visit_column_default(
element: ColumnDefault, compiler: MSDDLCompiler, **kw
) -> str:
# TODO: there can also be a named constraint
# with ADD CONSTRAINT here
return "%s ADD DEFAULT %s FOR %s" % (
alter_table(compiler, element.table_name, element.schema),
format_server_default(compiler, element.default),
format_column_name(compiler, element.column_name),
)
@compiles(ColumnName, "mssql")
def visit_rename_column(
element: ColumnName, compiler: MSDDLCompiler, **kw
) -> str:
return "EXEC sp_rename '%s.%s', %s, 'COLUMN'" % (
format_table_name(compiler, element.table_name, element.schema),
format_column_name(compiler, element.column_name),
format_column_name(compiler, element.newname),
)
@compiles(ColumnType, "mssql")
def visit_column_type(
element: ColumnType, compiler: MSDDLCompiler, **kw
) -> str:
return "%s %s %s" % (
alter_table(compiler, element.table_name, element.schema),
alter_column(compiler, element.column_name),
format_type(compiler, element.type_),
)
@compiles(RenameTable, "mssql")
def visit_rename_table(
element: RenameTable, compiler: MSDDLCompiler, **kw
) -> str:
return "EXEC sp_rename '%s', %s" % (
format_table_name(compiler, element.table_name, element.schema),
format_table_name(compiler, element.new_table_name, None),
)
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