diff options
Diffstat (limited to 'lib/sqlalchemy/sql/schema.py')
| -rw-r--r-- | lib/sqlalchemy/sql/schema.py | 59 |
1 files changed, 44 insertions, 15 deletions
diff --git a/lib/sqlalchemy/sql/schema.py b/lib/sqlalchemy/sql/schema.py index 36d69456e..f420eb621 100644 --- a/lib/sqlalchemy/sql/schema.py +++ b/lib/sqlalchemy/sql/schema.py @@ -70,6 +70,17 @@ BLANK_SCHEMA = util.symbol( """, ) +NULL_UNSPECIFIED = util.symbol( + "NULL_UNSPECIFIED", + """Symbol indicating the "nullable" keyword was not passed to a Column. + + Normally we would expect None to be acceptable for this but some backends + such as that of SQL Server place special signficance on a "nullability" + value of None. + + """, +) + def _get_table_key(name, schema): if schema is None: @@ -1257,11 +1268,18 @@ class Column(DialectKWArgs, SchemaItem, ColumnClause): phrase to be added when generating DDL for the column. When ``True``, will normally generate nothing (in SQL this defaults to "NULL"), except in some very specific backend-specific edge cases - where "NULL" may render explicitly. Defaults to ``True`` unless - :paramref:`_schema.Column.primary_key` is also ``True``, - in which case it - defaults to ``False``. This parameter is only used when issuing - CREATE TABLE statements. + where "NULL" may render explicitly. + Defaults to ``True`` unless :paramref:`_schema.Column.primary_key` + is also ``True`` or the column specifies a :class:`_sql.Identity`, + in which case it defaults to ``False``. + This parameter is only used when issuing CREATE TABLE statements. + + .. note:: + + When the column specifies a :class:`_sql.Identity` this + parameter is in general ignored by the DDL compiler. The + PostgreSQL database allows nullable identity column by + setting this parameter to ``True`` explicitly. :param onupdate: A scalar, Python callable, or :class:`~sqlalchemy.sql.expression.ClauseElement` representing a @@ -1393,8 +1411,17 @@ class Column(DialectKWArgs, SchemaItem, ColumnClause): super(Column, self).__init__(name, type_) self.key = kwargs.pop("key", name) - self.primary_key = kwargs.pop("primary_key", False) - self.nullable = kwargs.pop("nullable", not self.primary_key) + self.primary_key = primary_key = kwargs.pop("primary_key", False) + + self._user_defined_nullable = udn = kwargs.pop( + "nullable", NULL_UNSPECIFIED + ) + + if udn is not NULL_UNSPECIFIED: + self.nullable = udn + else: + self.nullable = not primary_key + self.default = kwargs.pop("default", None) self.server_default = kwargs.pop("server_default", None) self.server_onupdate = kwargs.pop("server_onupdate", None) @@ -1466,10 +1493,6 @@ class Column(DialectKWArgs, SchemaItem, ColumnClause): def _extra_kwargs(self, **kwargs): self._validate_dialect_kwargs(kwargs) - # @property - # def quote(self): - # return getattr(self.name, "quote", None) - def __str__(self): if self.name is None: return "(no name)" @@ -1664,12 +1687,14 @@ class Column(DialectKWArgs, SchemaItem, ColumnClause): if isinstance(type_, SchemaEventTarget): type_ = type_.copy(**kw) + if self._user_defined_nullable is not NULL_UNSPECIFIED: + column_kwargs["nullable"] = self._user_defined_nullable + c = self._constructor( name=self.name, type_=type_, key=self.key, primary_key=self.primary_key, - nullable=self.nullable, unique=self.unique, system=self.system, # quote=self.quote, # disabled 2013-08-27 (commit 031ef080) @@ -3596,7 +3621,8 @@ class PrimaryKeyConstraint(ColumnCollectionConstraint): for c in self.columns: c.primary_key = True - c.nullable = False + if c._user_defined_nullable is NULL_UNSPECIFIED: + c.nullable = False if table_pks: self.columns.extend(table_pks) @@ -4777,9 +4803,12 @@ class Identity(IdentityOptions, FetchedValue, SchemaItem): "autoincrement=False" ) self.column = parent + parent.identity = self - # self.column.server_onupdate = self - self.column.server_default = self + if parent._user_defined_nullable is NULL_UNSPECIFIED: + parent.nullable = False + + parent.server_default = self def _as_for_update(self, for_update): return self |