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Python

4 years ago
import re
from sqlalchemy import schema
from sqlalchemy import types as sqltypes
from sqlalchemy.ext.compiler import compiles
from .base import alter_table
from .base import AlterColumn
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 .impl import DefaultImpl
from .. import util
from ..autogenerate import compare
from ..util.compat import string_types
from ..util.sqla_compat import _is_mariadb
from ..util.sqla_compat import _is_type_bound
class MySQLImpl(DefaultImpl):
__dialect__ = "mysql"
transactional_ddl = False
type_synonyms = DefaultImpl.type_synonyms + ({"BOOL", "TINYINT"},)
type_arg_extract = [r"character set ([\w\-_]+)", r"collate ([\w\-_]+)"]
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,
autoincrement=None,
existing_autoincrement=None,
comment=False,
existing_comment=None,
**kw
):
if name is not None or self._is_mysql_allowed_functional_default(
type_ if type_ is not None else existing_type, server_default
):
self._exec(
MySQLChangeColumn(
table_name,
column_name,
schema=schema,
newname=name if name is not None else column_name,
nullable=nullable
if nullable is not None
else existing_nullable
if existing_nullable is not None
else True,
type_=type_ if type_ is not None else existing_type,
default=server_default
if server_default is not False
else existing_server_default,
autoincrement=autoincrement
if autoincrement is not None
else existing_autoincrement,
comment=comment
if comment is not False
else existing_comment,
)
)
elif (
nullable is not None
or type_ is not None
or autoincrement is not None
or comment is not False
):
self._exec(
MySQLModifyColumn(
table_name,
column_name,
schema=schema,
newname=name if name is not None else column_name,
nullable=nullable
if nullable is not None
else existing_nullable
if existing_nullable is not None
else True,
type_=type_ if type_ is not None else existing_type,
default=server_default
if server_default is not False
else existing_server_default,
autoincrement=autoincrement
if autoincrement is not None
else existing_autoincrement,
comment=comment
if comment is not False
else existing_comment,
)
)
elif server_default is not False:
self._exec(
MySQLAlterDefault(
table_name, column_name, server_default, schema=schema
)
)
def drop_constraint(self, const):
if isinstance(const, schema.CheckConstraint) and _is_type_bound(const):
return
super(MySQLImpl, self).drop_constraint(const)
def _is_mysql_allowed_functional_default(self, type_, server_default):
return (
type_ is not None
and type_._type_affinity is sqltypes.DateTime
and server_default is not None
)
def compare_server_default(
self,
inspector_column,
metadata_column,
rendered_metadata_default,
rendered_inspector_default,
):
# partially a workaround for SQLAlchemy issue #3023; if the
# column were created without "NOT NULL", MySQL may have added
# an implicit default of '0' which we need to skip
# TODO: this is not really covered anymore ?
if (
metadata_column.type._type_affinity is sqltypes.Integer
and inspector_column.primary_key
and not inspector_column.autoincrement
and not rendered_metadata_default
and rendered_inspector_default == "'0'"
):
return False
elif inspector_column.type._type_affinity is sqltypes.Integer:
rendered_inspector_default = (
re.sub(r"^'|'$", "", rendered_inspector_default)
if rendered_inspector_default is not None
else None
)
return rendered_inspector_default != rendered_metadata_default
elif rendered_inspector_default and rendered_metadata_default:
# adjust for "function()" vs. "FUNCTION" as can occur particularly
# for the CURRENT_TIMESTAMP function on newer MariaDB versions
# SQLAlchemy MySQL dialect bundles ON UPDATE into the server
# default; adjust for this possibly being present.
onupdate_ins = re.match(
r"(.*) (on update.*?)(?:\(\))?$",
rendered_inspector_default.lower(),
)
onupdate_met = re.match(
r"(.*) (on update.*?)(?:\(\))?$",
rendered_metadata_default.lower(),
)
if onupdate_ins:
if not onupdate_met:
return True
elif onupdate_ins.group(2) != onupdate_met.group(2):
return True
rendered_inspector_default = onupdate_ins.group(1)
rendered_metadata_default = onupdate_met.group(1)
return re.sub(
r"(.*?)(?:\(\))?$", r"\1", rendered_inspector_default.lower()
) != re.sub(
r"(.*?)(?:\(\))?$", r"\1", rendered_metadata_default.lower()
)
else:
return rendered_inspector_default != rendered_metadata_default
def correct_for_autogen_constraints(
self,
conn_unique_constraints,
conn_indexes,
metadata_unique_constraints,
metadata_indexes,
):
# TODO: if SQLA 1.0, make use of "duplicates_index"
# metadata
removed = set()
for idx in list(conn_indexes):
if idx.unique:
continue
# MySQL puts implicit indexes on FK columns, even if
# composite and even if MyISAM, so can't check this too easily.
# the name of the index may be the column name or it may
# be the name of the FK constraint.
for col in idx.columns:
if idx.name == col.name:
conn_indexes.remove(idx)
removed.add(idx.name)
break
for fk in col.foreign_keys:
if fk.name == idx.name:
conn_indexes.remove(idx)
removed.add(idx.name)
break
if idx.name in removed:
break
# then remove indexes from the "metadata_indexes"
# that we've removed from reflected, otherwise they come out
# as adds (see #202)
for idx in list(metadata_indexes):
if idx.name in removed:
metadata_indexes.remove(idx)
def correct_for_autogen_foreignkeys(self, conn_fks, metadata_fks):
conn_fk_by_sig = dict(
(compare._fk_constraint_sig(fk).sig, fk) for fk in conn_fks
)
metadata_fk_by_sig = dict(
(compare._fk_constraint_sig(fk).sig, fk) for fk in metadata_fks
)
for sig in set(conn_fk_by_sig).intersection(metadata_fk_by_sig):
mdfk = metadata_fk_by_sig[sig]
cnfk = conn_fk_by_sig[sig]
# MySQL considers RESTRICT to be the default and doesn't
# report on it. if the model has explicit RESTRICT and
# the conn FK has None, set it to RESTRICT
if (
mdfk.ondelete is not None
and mdfk.ondelete.lower() == "restrict"
and cnfk.ondelete is None
):
cnfk.ondelete = "RESTRICT"
if (
mdfk.onupdate is not None
and mdfk.onupdate.lower() == "restrict"
and cnfk.onupdate is None
):
cnfk.onupdate = "RESTRICT"
class MySQLAlterDefault(AlterColumn):
def __init__(self, name, column_name, default, schema=None):
super(AlterColumn, self).__init__(name, schema=schema)
self.column_name = column_name
self.default = default
class MySQLChangeColumn(AlterColumn):
def __init__(
self,
name,
column_name,
schema=None,
newname=None,
type_=None,
nullable=None,
default=False,
autoincrement=None,
comment=False,
):
super(AlterColumn, self).__init__(name, schema=schema)
self.column_name = column_name
self.nullable = nullable
self.newname = newname
self.default = default
self.autoincrement = autoincrement
self.comment = comment
if type_ is None:
raise util.CommandError(
"All MySQL CHANGE/MODIFY COLUMN operations "
"require the existing type."
)
self.type_ = sqltypes.to_instance(type_)
class MySQLModifyColumn(MySQLChangeColumn):
pass
@compiles(ColumnNullable, "mysql")
@compiles(ColumnName, "mysql")
@compiles(ColumnDefault, "mysql")
@compiles(ColumnType, "mysql")
def _mysql_doesnt_support_individual(element, compiler, **kw):
raise NotImplementedError(
"Individual alter column constructs not supported by MySQL"
)
@compiles(MySQLAlterDefault, "mysql")
def _mysql_alter_default(element, compiler, **kw):
return "%s ALTER COLUMN %s %s" % (
alter_table(compiler, element.table_name, element.schema),
format_column_name(compiler, element.column_name),
"SET DEFAULT %s" % format_server_default(compiler, element.default)
if element.default is not None
else "DROP DEFAULT",
)
@compiles(MySQLModifyColumn, "mysql")
def _mysql_modify_column(element, compiler, **kw):
return "%s MODIFY %s %s" % (
alter_table(compiler, element.table_name, element.schema),
format_column_name(compiler, element.column_name),
_mysql_colspec(
compiler,
nullable=element.nullable,
server_default=element.default,
type_=element.type_,
autoincrement=element.autoincrement,
comment=element.comment,
),
)
@compiles(MySQLChangeColumn, "mysql")
def _mysql_change_column(element, compiler, **kw):
return "%s CHANGE %s %s %s" % (
alter_table(compiler, element.table_name, element.schema),
format_column_name(compiler, element.column_name),
format_column_name(compiler, element.newname),
_mysql_colspec(
compiler,
nullable=element.nullable,
server_default=element.default,
type_=element.type_,
autoincrement=element.autoincrement,
comment=element.comment,
),
)
def _render_value(compiler, expr):
if isinstance(expr, string_types):
return "'%s'" % expr
else:
return compiler.sql_compiler.process(expr)
def _mysql_colspec(
compiler, nullable, server_default, type_, autoincrement, comment
):
spec = "%s %s" % (
compiler.dialect.type_compiler.process(type_),
"NULL" if nullable else "NOT NULL",
)
if autoincrement:
spec += " AUTO_INCREMENT"
if server_default is not False and server_default is not None:
spec += " DEFAULT %s" % _render_value(compiler, server_default)
if comment:
spec += " COMMENT %s" % compiler.sql_compiler.render_literal_value(
comment, sqltypes.String()
)
return spec
@compiles(schema.DropConstraint, "mysql")
def _mysql_drop_constraint(element, compiler, **kw):
"""Redefine SQLAlchemy's drop constraint to
raise errors for invalid constraint type."""
constraint = element.element
if isinstance(
constraint,
(
schema.ForeignKeyConstraint,
schema.PrimaryKeyConstraint,
schema.UniqueConstraint,
),
):
return compiler.visit_drop_constraint(element, **kw)
elif isinstance(constraint, schema.CheckConstraint):
# note that SQLAlchemy as of 1.2 does not yet support
# DROP CONSTRAINT for MySQL/MariaDB, so we implement fully
# here.
if _is_mariadb(compiler.dialect):
return "ALTER TABLE %s DROP CONSTRAINT %s" % (
compiler.preparer.format_table(constraint.table),
compiler.preparer.format_constraint(constraint),
)
else:
return "ALTER TABLE %s DROP CHECK %s" % (
compiler.preparer.format_table(constraint.table),
compiler.preparer.format_constraint(constraint),
)
else:
raise NotImplementedError(
"No generic 'DROP CONSTRAINT' in MySQL - "
"please specify constraint type"
)