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from typing import Any
from typing import Dict
from typing import List
from typing import Optional
from typing import Sequence
from typing import Tuple
from typing import TYPE_CHECKING
from typing import Union
from sqlalchemy import schema as sa_schema
from sqlalchemy.sql.schema import Column
from sqlalchemy.sql.schema import Constraint
from sqlalchemy.sql.schema import Index
from sqlalchemy.types import Integer
from sqlalchemy.types import NULLTYPE
from .. import util
from ..util import sqla_compat
from ..util.compat import string_types
if TYPE_CHECKING:
from sqlalchemy.sql.elements import ColumnElement
from sqlalchemy.sql.elements import TextClause
from sqlalchemy.sql.schema import CheckConstraint
from sqlalchemy.sql.schema import ForeignKey
from sqlalchemy.sql.schema import ForeignKeyConstraint
from sqlalchemy.sql.schema import MetaData
from sqlalchemy.sql.schema import PrimaryKeyConstraint
from sqlalchemy.sql.schema import Table
from sqlalchemy.sql.schema import UniqueConstraint
from sqlalchemy.sql.type_api import TypeEngine
from ..runtime.migration import MigrationContext
class SchemaObjects:
def __init__(
self, migration_context: Optional["MigrationContext"] = None
) -> None:
self.migration_context = migration_context
def primary_key_constraint(
self,
name: Optional[str],
table_name: str,
cols: Sequence[str],
schema: Optional[str] = None,
**dialect_kw
) -> "PrimaryKeyConstraint":
m = self.metadata()
columns = [sa_schema.Column(n, NULLTYPE) for n in cols]
t = sa_schema.Table(table_name, m, *columns, schema=schema)
p = sa_schema.PrimaryKeyConstraint(
*[t.c[n] for n in cols], name=name, **dialect_kw
)
return p
def foreign_key_constraint(
self,
name: Optional[str],
source: str,
referent: str,
local_cols: List[str],
remote_cols: List[str],
onupdate: Optional[str] = None,
ondelete: Optional[str] = None,
deferrable: Optional[bool] = None,
source_schema: Optional[str] = None,
referent_schema: Optional[str] = None,
initially: Optional[str] = None,
match: Optional[str] = None,
**dialect_kw
) -> "ForeignKeyConstraint":
m = self.metadata()
if source == referent and source_schema == referent_schema:
t1_cols = local_cols + remote_cols
else:
t1_cols = local_cols
sa_schema.Table(
referent,
m,
*[sa_schema.Column(n, NULLTYPE) for n in remote_cols],
schema=referent_schema
)
t1 = sa_schema.Table(
source,
m,
*[sa_schema.Column(n, NULLTYPE) for n in t1_cols],
schema=source_schema
)
tname = (
"%s.%s" % (referent_schema, referent)
if referent_schema
else referent
)
dialect_kw["match"] = match
f = sa_schema.ForeignKeyConstraint(
local_cols,
["%s.%s" % (tname, n) for n in remote_cols],
name=name,
onupdate=onupdate,
ondelete=ondelete,
deferrable=deferrable,
initially=initially,
**dialect_kw
)
t1.append_constraint(f)
return f
def unique_constraint(
self,
name: Optional[str],
source: str,
local_cols: Sequence[str],
schema: Optional[str] = None,
**kw
) -> "UniqueConstraint":
t = sa_schema.Table(
source,
self.metadata(),
*[sa_schema.Column(n, NULLTYPE) for n in local_cols],
schema=schema
)
kw["name"] = name
uq = sa_schema.UniqueConstraint(*[t.c[n] for n in local_cols], **kw)
# TODO: need event tests to ensure the event
# is fired off here
t.append_constraint(uq)
return uq
def check_constraint(
self,
name: Optional[str],
source: str,
condition: Union[str, "TextClause", "ColumnElement[Any]"],
schema: Optional[str] = None,
**kw
) -> Union["CheckConstraint"]:
t = sa_schema.Table(
source,
self.metadata(),
sa_schema.Column("x", Integer),
schema=schema,
)
ck = sa_schema.CheckConstraint(condition, name=name, **kw)
t.append_constraint(ck)
return ck
def generic_constraint(
self,
name: Optional[str],
table_name: str,
type_: Optional[str],
schema: Optional[str] = None,
**kw
) -> Any:
t = self.table(table_name, schema=schema)
types: Dict[Optional[str], Any] = {
"foreignkey": lambda name: sa_schema.ForeignKeyConstraint(
[], [], name=name
),
"primary": sa_schema.PrimaryKeyConstraint,
"unique": sa_schema.UniqueConstraint,
"check": lambda name: sa_schema.CheckConstraint("", name=name),
None: sa_schema.Constraint,
}
try:
const = types[type_]
except KeyError as ke:
raise TypeError(
"'type' can be one of %s"
% ", ".join(sorted(repr(x) for x in types))
) from ke
else:
const = const(name=name)
t.append_constraint(const)
return const
def metadata(self) -> "MetaData":
kw = {}
if (
self.migration_context is not None
and "target_metadata" in self.migration_context.opts
):
mt = self.migration_context.opts["target_metadata"]
if hasattr(mt, "naming_convention"):
kw["naming_convention"] = mt.naming_convention
return sa_schema.MetaData(**kw)
def table(self, name: str, *columns, **kw) -> "Table":
m = self.metadata()
cols = [
sqla_compat._copy(c) if c.table is not None else c
for c in columns
if isinstance(c, Column)
]
# these flags have already added their UniqueConstraint /
# Index objects to the table, so flip them off here.
# SQLAlchemy tometadata() avoids this instead by preserving the
# flags and skipping the constraints that have _type_bound on them,
# but for a migration we'd rather list out the constraints
# explicitly.
_constraints_included = kw.pop("_constraints_included", False)
if _constraints_included:
for c in cols:
c.unique = c.index = False
t = sa_schema.Table(name, m, *cols, **kw)
constraints = [
sqla_compat._copy(elem, target_table=t)
if getattr(elem, "parent", None) is not None
else elem
for elem in columns
if isinstance(elem, (Constraint, Index))
]
for const in constraints:
t.append_constraint(const)
for f in t.foreign_keys:
self._ensure_table_for_fk(m, f)
return t
def column(self, name: str, type_: "TypeEngine", **kw) -> "Column":
return sa_schema.Column(name, type_, **kw)
def index(
self,
name: str,
tablename: Optional[str],
columns: Sequence[Union[str, "TextClause", "ColumnElement[Any]"]],
schema: Optional[str] = None,
**kw
) -> "Index":
t = sa_schema.Table(
tablename or "no_table",
self.metadata(),
schema=schema,
)
kw["_table"] = t
idx = sa_schema.Index(
name,
*[util.sqla_compat._textual_index_column(t, n) for n in columns],
**kw
)
return idx
def _parse_table_key(self, table_key: str) -> Tuple[Optional[str], str]:
if "." in table_key:
tokens = table_key.split(".")
sname: Optional[str] = ".".join(tokens[0:-1])
tname = tokens[-1]
else:
tname = table_key
sname = None
return (sname, tname)
def _ensure_table_for_fk(
self, metadata: "MetaData", fk: "ForeignKey"
) -> None:
"""create a placeholder Table object for the referent of a
ForeignKey.
"""
if isinstance(fk._colspec, string_types): # type:ignore[attr-defined]
table_key, cname = fk._colspec.rsplit( # type:ignore[attr-defined]
".", 1
)
sname, tname = self._parse_table_key(table_key)
if table_key not in metadata.tables:
rel_t = sa_schema.Table(tname, metadata, schema=sname)
else:
rel_t = metadata.tables[table_key]
if cname not in rel_t.c:
rel_t.append_column(sa_schema.Column(cname, NULLTYPE))
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