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File Content: `mssql.py`

from sqlalchemy.ext.compiler import compiles

from .. import util
from .impl import DefaultImpl
from .base import alter_table, AddColumn, ColumnName, RenameTable,\
    format_table_name, format_column_name, ColumnNullable, alter_column,\
    format_server_default, ColumnDefault, format_type, ColumnType
from sqlalchemy.sql.expression import ClauseElement, Executable


class MSSQLImpl(DefaultImpl):
    __dialect__ = 'mssql'
    transactional_ddl = True
    batch_separator = "GO"

    def __init__(self, *arg, **kw):
        super(MSSQLImpl, self).__init__(*arg, **kw)
        self.batch_separator = self.context_opts.get(
            "mssql_batch_separator",
            self.batch_separator)

    def _exec(self, construct, *args, **kw):
        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):
        self.static_output("BEGIN TRANSACTION" + self.command_terminator)

    def emit_commit(self):
        super(MSSQLImpl, self).emit_commit()
        if self.as_sql and self.batch_separator:
            self.static_output(self.batch_separator)

    def alter_column(self, table_name, column_name,
                     nullable=None,
                     server_default=False,
                     name=None,
                     type_=None,
                     schema=None,
                     existing_type=None,
                     existing_server_default=None,
                     existing_nullable=None,
                     **kw
                     ):

        if nullable is not None and existing_type is None:
            if type_ is not None:
                existing_type = type_
                # the NULL/NOT NULL alter will handle
                # the type alteration
                type_ = None
            else:
                raise util.CommandError(
                    "MS-SQL ALTER COLUMN operations "
                    "with NULL or NOT NULL require the "
                    "existing_type or a new type_ be passed.")

        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:
            if existing_server_default is not False or \
                    server_default is None:
                self._exec(
                    _ExecDropConstraint(
                        table_name, column_name,
                        'sys.default_constraints')
                )
            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 bulk_insert(self, table, rows, **kw):
        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, column, **kw):
        drop_default = kw.pop('mssql_drop_default', False)
        if drop_default:
            self._exec(
                _ExecDropConstraint(
                    table_name, column,
                    'sys.default_constraints')
            )
        drop_check = kw.pop('mssql_drop_check', False)
        if drop_check:
            self._exec(
                _ExecDropConstraint(
                    table_name, column,
                    'sys.check_constraints')
            )
        drop_fks = kw.pop('mssql_drop_foreign_key', False)
        if drop_fks:
            self._exec(
                _ExecDropFKConstraint(table_name, column)
            )
        super(MSSQLImpl, self).drop_column(table_name, column, **kw)


class _ExecDropConstraint(Executable, ClauseElement):

    def __init__(self, tname, colname, type_):
        self.tname = tname
        self.colname = colname
        self.type_ = type_


class _ExecDropFKConstraint(Executable, ClauseElement):

    def __init__(self, tname, colname):
        self.tname = tname
        self.colname = colname


@compiles(_ExecDropConstraint, 'mssql')
def _exec_drop_col_constraint(element, compiler, **kw):
    tname, colname, type_ = 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('%(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, None),
    }


@compiles(_ExecDropFKConstraint, 'mssql')
def _exec_drop_col_fk_constraint(element, compiler, **kw):
    tname, colname = 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('%(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, None),
    }


@compiles(AddColumn, 'mssql')
def visit_add_column(element, compiler, **kw):
    return "%s %s" % (
        alter_table(compiler, element.table_name, element.schema),
        mssql_add_column(compiler, element.column, **kw)
    )


def mssql_add_column(compiler, column, **kw):
    return "ADD %s" % compiler.get_column_specification(column, **kw)


@compiles(ColumnNullable, 'mssql')
def visit_column_nullable(element, compiler, **kw):
    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, compiler, **kw):
    # 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, compiler, **kw):
    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, compiler, **kw):
    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, compiler, **kw):
    return "EXEC sp_rename '%s', %s" % (
        format_table_name(compiler, element.table_name, element.schema),
        format_table_name(compiler, element.new_table_name, element.schema)
    )
Name	Size	Permission
__init__.py	125 bytes	0644
__init__.pyc	346 bytes	0644
__init__.pyo	346 bytes	0644
base.py	5924 bytes	0644
base.pyc	9740 bytes	0644
base.pyo	9740 bytes	0644
impl.py	12085 bytes	0644
impl.pyc	13677 bytes	0644
impl.pyo	13677 bytes	0644
mssql.py	8178 bytes	0644
mssql.pyc	8724 bytes	0644
mssql.pyo	8724 bytes	0644
mysql.py	11684 bytes	0644
mysql.pyc	9771 bytes	0644
mysql.pyo	9771 bytes	0644
oracle.py	2687 bytes	0644
oracle.pyc	4181 bytes	0644
oracle.pyo	4181 bytes	0644
postgresql.py	5324 bytes	0644
postgresql.pyc	5262 bytes	0644
postgresql.pyo	5262 bytes	0644
sqlite.py	3521 bytes	0644
sqlite.pyc	3258 bytes	0644
sqlite.pyo	3258 bytes	0644
File Content: mssql.py

File Content: `mssql.py`
