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Edit File: mssql.py
from __future__ import annotations 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.engine.cursor import LegacyCursorResult 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(MSSQLImpl, self).__init__(*arg, **kw) self.batch_separator = self.context_opts.get( "mssql_batch_separator", self.batch_separator ) def _exec( self, construct: Any, *args, **kw ) -> Optional[Union["LegacyCursorResult", "CursorResult"]]: result = super(MSSQLImpl, self)._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(MSSQLImpl, self).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(MSSQLImpl, self).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(MSSQLImpl, self).alter_column( table_name, column_name, schema=schema, server_default=server_default, ) if name is not None: super(MSSQLImpl, self).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(MSSQLImpl, self).bulk_insert(table, rows, **kw) self._exec( "SET IDENTITY_INSERT %s OFF" % self.dialect.identifier_preparer.format_table(table) ) else: super(MSSQLImpl, self).bulk_insert(table, rows, **kw) def drop_column( self, table_name: str, column: "Column", 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(MSSQLImpl, self).drop_column( table_name, column, schema=schema, **kw ) def compare_server_default( self, inspector_column, metadata_column, rendered_metadata_default, rendered_inspector_default, ): def clean(value): if value is not None: value = value.strip() while value[0] == "(" and value[-1] == ")": value = value[1:-1] return value return clean(rendered_inspector_default) != clean( rendered_metadata_default ) def _compare_identity_default(self, metadata_identity, inspector_identity): diff, ignored, is_alter = super( MSSQLImpl, self )._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", 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", 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/ # TODO: needs table formatting, etc. return """declare @const_name varchar(256) select @const_name = [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 = [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", **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), "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), )