我们从Python开源项目中，提取了以下32个代码示例，用于说明如何使用sqlalchemy.schema.DefaultClause()。
def _render_server_default_for_compare(metadata_default, metadata_col, autogen_context): rendered = _user_defined_render( "server_default", metadata_default, autogen_context) if rendered is not False: return rendered if isinstance(metadata_default, sa_schema.DefaultClause): if isinstance(metadata_default.arg, compat.string_types): metadata_default = metadata_default.arg else: metadata_default = str(metadata_default.arg.compile( dialect=autogen_context.dialect)) if isinstance(metadata_default, compat.string_types): if metadata_col.type._type_affinity is sqltypes.String: metadata_default = re.sub(r"^'|'$", "", metadata_default) return repr(metadata_default) else: return metadata_default else: return None
def _render_server_default(default, autogen_context): rendered = _user_defined_render("server_default", default, autogen_context) if rendered is not False: return rendered if isinstance(default, sa_schema.DefaultClause): if isinstance(default.arg, string_types): default = default.arg else: default = str(default.arg.compile( dialect=autogen_context['dialect'])) if isinstance(default, string_types): # TODO: this is just a hack to get # tests to pass until we figure out # WTF sqlite is doing default = re.sub(r"^'|'$", "", default) return repr(default) else: return None
def _render_server_default_for_compare(metadata_default, metadata_col, autogen_context): rendered = _user_defined_render( "server_default", metadata_default, autogen_context) if rendered is not False: return rendered if isinstance(metadata_default, sa_schema.DefaultClause): if isinstance(metadata_default.arg, compat.string_types): metadata_default = metadata_default.arg else: metadata_default = str(metadata_default.arg.compile( dialect=autogen_context['dialect'])) if isinstance(metadata_default, compat.string_types): if metadata_col.type._type_affinity is sqltypes.String: metadata_default = re.sub(r"^'|'$", "", metadata_default) return repr(metadata_default) else: return metadata_default else: return None
def _render_server_default(default, autogen_context, repr_=True): rendered = _user_defined_render("server_default", default, autogen_context) if rendered is not False: return rendered if isinstance(default, sa_schema.DefaultClause): if isinstance(default.arg, compat.string_types): default = default.arg else: return _render_potential_expr(default.arg, autogen_context) if isinstance(default, string_types) and repr_: default = repr(re.sub(r"^'|'$", "", default)) return default
def alter_column(self, table_name, column_name, nullable=None, server_default=False, name=None, type_=None, autoincrement=None, **kw ): existing = self.columns[column_name] existing_transfer = self.column_transfers[column_name] if name is not None and name != column_name: # note that we don't change '.key' - we keep referring # to the renamed column by its old key in _create(). neat! existing.name = name existing_transfer["name"] = name if type_ is not None: type_ = sqltypes.to_instance(type_) # old type is being discarded so turn off eventing # rules. Alternatively we can # erase the events set up by this type, but this is simpler. # we also ignore the drop_constraint that will come here from # Operations.implementation_for(alter_column) if isinstance(existing.type, SchemaEventTarget): existing.type._create_events = \ existing.type.create_constraint = False existing.type = type_ # we *dont* however set events for the new type, because # alter_column is invoked from # Operations.implementation_for(alter_column) which already # will emit an add_constraint() existing_transfer["expr"] = cast(existing_transfer["expr"], type_) if nullable is not None: existing.nullable = nullable if server_default is not False: sql_schema.DefaultClause(server_default)._set_parent(existing) if autoincrement is not None: existing.autoincrement = bool(autoincrement)
def get_column_default_string(self, column): if (isinstance(column.server_default, schema.DefaultClause) and isinstance(column.server_default.arg, basestring)): if isinstance(column.type, (sqltypes.Integer, sqltypes.Numeric)): return self.sql_compiler.process(text(column.server_default.arg)) return super(InfoDDLCompiler, self).get_column_default_string(column) ### Informix wants the constraint name at the end, hence this ist c&p from sql/compiler.py
def alter_column(self, table_name, column_name, nullable=None, server_default=False, name=None, type_=None, autoincrement=None, **kw ): existing = self.columns[column_name] existing_transfer = self.column_transfers[column_name] if name is not None and name != column_name: # note that we don't change '.key' - we keep referring # to the renamed column by its old key in _create(). neat! existing.name = name existing_transfer["name"] = name if type_ is not None: type_ = sqltypes.to_instance(type_) # old type is being discarded so turn off eventing # rules. Alternatively we can # erase the events set up by this type, but this is simpler. # we also ignore the drop_constraint that will come here from # Operations.implementation_for(alter_column) if isinstance(existing.type, SchemaEventTarget): existing.type._create_events = \ existing.type.create_constraint = False existing.type = type_ # we *dont* however set events for the new type, because # alter_column is invoked from # Operations.implementation_for(alter_column) which already # will emit an add_constraint() existing_transfer["expr"] = cast(existing_transfer["expr"], type_) if nullable is not None: existing.nullable = nullable if server_default is not False: if server_default is None: existing.server_default = None else: sql_schema.DefaultClause(server_default)._set_parent(existing) if autoincrement is not None: existing.autoincrement = bool(autoincrement)
def alter_column(self, table_name, column_name, nullable=None, server_default=False, name=None, type_=None, autoincrement=None, **kw ): existing = self.columns[column_name] existing_transfer = self.column_transfers[column_name] if name is not None and name != column_name: # note that we don't change '.key' - we keep referring # to the renamed column by its old key in _create(). neat! existing.name = name existing_transfer["name"] = name if type_ is not None: type_ = sqltypes.to_instance(type_) # old type is being discarded so turn off eventing # rules. Alternatively we can # erase the events set up by this type, but this is simpler. # we also ignore the drop_constraint that will come here from # Operations.implementation_for(alter_column) if isinstance(existing.type, SchemaEventTarget): existing.type._create_events = \ existing.type.create_constraint = False if existing.type._type_affinity is not type_._type_affinity: existing_transfer["expr"] = cast( existing_transfer["expr"], type_) existing.type = type_ # we *dont* however set events for the new type, because # alter_column is invoked from # Operations.implementation_for(alter_column) which already # will emit an add_constraint() if nullable is not None: existing.nullable = nullable if server_default is not False: if server_default is None: existing.server_default = None else: sql_schema.DefaultClause(server_default)._set_parent(existing) if autoincrement is not None: existing.autoincrement = bool(autoincrement)
