JezK
Edit File: naming.py
# sqlalchemy/naming.py # Copyright (C) 2005-2023 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under # the MIT License: https://www.opensource.org/licenses/mit-license.php """Establish constraint and index naming conventions. """ import re from . import events # noqa from .elements import _NONE_NAME from .elements import conv from .schema import CheckConstraint from .schema import Column from .schema import Constraint from .schema import ForeignKeyConstraint from .schema import Index from .schema import PrimaryKeyConstraint from .schema import Table from .schema import UniqueConstraint from .. import event from .. import exc class ConventionDict(object): def __init__(self, const, table, convention): self.const = const self._is_fk = isinstance(const, ForeignKeyConstraint) self.table = table self.convention = convention self._const_name = const.name def _key_table_name(self): return self.table.name def _column_X(self, idx, attrname): if self._is_fk: try: fk = self.const.elements[idx] except IndexError: return "" else: return getattr(fk.parent, attrname) else: cols = list(self.const.columns) try: col = cols[idx] except IndexError: return "" else: return getattr(col, attrname) def _key_constraint_name(self): if self._const_name in (None, _NONE_NAME): raise exc.InvalidRequestError( "Naming convention including " "%(constraint_name)s token requires that " "constraint is explicitly named." ) if not isinstance(self._const_name, conv): self.const.name = None return self._const_name def _key_column_X_key(self, idx): # note this method was missing before # [ticket:3989], meaning tokens like ``%(column_0_key)s`` weren't # working even though documented. return self._column_X(idx, "key") def _key_column_X_name(self, idx): return self._column_X(idx, "name") def _key_column_X_label(self, idx): return self._column_X(idx, "_ddl_label") def _key_referred_table_name(self): fk = self.const.elements[0] refs = fk.target_fullname.split(".") if len(refs) == 3: refschema, reftable, refcol = refs else: reftable, refcol = refs return reftable def _key_referred_column_X_name(self, idx): fk = self.const.elements[idx] # note that before [ticket:3989], this method was returning # the specification for the :class:`.ForeignKey` itself, which normally # would be using the ``.key`` of the column, not the name. return fk.column.name def __getitem__(self, key): if key in self.convention: return self.convention[key](self.const, self.table) elif hasattr(self, "_key_%s" % key): return getattr(self, "_key_%s" % key)() else: col_template = re.match(r".*_?column_(\d+)(_?N)?_.+", key) if col_template: idx = col_template.group(1) multiples = col_template.group(2) if multiples: if self._is_fk: elems = self.const.elements else: elems = list(self.const.columns) tokens = [] for idx, elem in enumerate(elems): attr = "_key_" + key.replace("0" + multiples, "X") try: tokens.append(getattr(self, attr)(idx)) except AttributeError: raise KeyError(key) sep = "_" if multiples.startswith("_") else "" return sep.join(tokens) else: attr = "_key_" + key.replace(idx, "X") idx = int(idx) if hasattr(self, attr): return getattr(self, attr)(idx) raise KeyError(key) _prefix_dict = { Index: "ix", PrimaryKeyConstraint: "pk", CheckConstraint: "ck", UniqueConstraint: "uq", ForeignKeyConstraint: "fk", } def _get_convention(dict_, key): for super_ in key.__mro__: if super_ in _prefix_dict and _prefix_dict[super_] in dict_: return dict_[_prefix_dict[super_]] elif super_ in dict_: return dict_[super_] else: return None def _constraint_name_for_table(const, table): metadata = table.metadata convention = _get_convention(metadata.naming_convention, type(const)) if isinstance(const.name, conv): return const.name elif ( convention is not None and not isinstance(const.name, conv) and ( const.name is None or "constraint_name" in convention or const.name is _NONE_NAME ) ): return conv( convention % ConventionDict(const, table, metadata.naming_convention) ) elif convention is _NONE_NAME: return None @event.listens_for( PrimaryKeyConstraint, "_sa_event_column_added_to_pk_constraint" ) def _column_added_to_pk_constraint(pk_constraint, col): if pk_constraint._implicit_generated: # only operate upon the "implicit" pk constraint for now, # as we have to force the name to None to reset it. the # "implicit" constraint will only have a naming convention name # if at all. table = pk_constraint.table pk_constraint.name = None newname = _constraint_name_for_table(pk_constraint, table) if newname: pk_constraint.name = newname @event.listens_for(Constraint, "after_parent_attach") @event.listens_for(Index, "after_parent_attach") def _constraint_name(const, table): if isinstance(table, Column): # this path occurs for a CheckConstraint linked to a Column # for column-attached constraint, set another event # to link the column attached to the table as this constraint # associated with the table. event.listen( table, "after_parent_attach", lambda col, table: _constraint_name(const, table), ) elif isinstance(table, Table): if isinstance(const.name, conv) or const.name is _NONE_NAME: return newname = _constraint_name_for_table(const, table) if newname: const.name = newname