Update declarative_styles.rst: Update code example to attrs TNG usage. (#8072)

* Update declarative_styles.rst

Update docs to new style usage of attrs.
This is the default since December 2021.
While the old style still works, the newer one looks much nicer and is likely to be dominant pretty quickly. Imho.

* Update declarative_styles.rst

* Update declarative_styles.rst

diff --git a/doc/build/orm/declarative_styles.rst b/doc/build/orm/declarative_styles.rst
index e39456c52a41728c1dc91fc227ec718343089a52..e9af7b4d325d9a5942f5884a1438d45911064ac7 100644 (file)
--- a/doc/build/orm/declarative_styles.rst
+++ b/doc/build/orm/declarative_styles.rst
@@ -195,19 +195,20 @@ Declarative Mapping with Dataclasses and Attrs
 The dataclasses_ module, added in Python 3.7, provides a ``@dataclass`` class
 decorator to automatically generate boilerplate definitions of ``__init__()``,
 ``__eq__()``, ``__repr()__``, etc. methods. Another very popular library that does
-the same, and much more, is attrs_.  Both libraries make use of class
-decorators in order to scan a class for attributes that define the class'
-behavior, which are then used to generate methods, documentation, and annotations.
+the same, and much more, is attrs_, which uses the ``@define`` decorator.
+Both libraries make use of class decorators in order to scan a class for
+attributes that define the class' behavior, which are then used to generate
+methods, documentation, and annotations.
 
 The :meth:`_orm.registry.mapped` class decorator allows the declarative mapping
 of a class to occur after the class has been fully constructed, allowing the
 class to be processed by other class decorators first.  The ``@dataclass``
-and ``@attr.s`` decorators may therefore be applied first before the
+and ``@define`` decorators may therefore be applied first before the
 ORM mapping process proceeds via the :meth:`_orm.registry.mapped` decorator
 or via the :meth:`_orm.registry.map_imperatively` method discussed in a
 later section.
 
-Mapping with ``@dataclass`` or ``@attr.s`` may be used in a straightforward
+Mapping with ``@dataclass`` or ``@define`` may be used in a straightforward
 way with :ref:`orm_imperative_table_configuration` style, where the
 the :class:`_schema.Table`, which means that it is defined separately and
 associated with the class via the ``__table__``.   For dataclasses specifically,
@@ -223,9 +224,13 @@ is to be mapped to a :class:`_schema.Column`, checks explicitly if the
 attribute is part of a Dataclasses setup, and if so will **replace**
 the class-bound dataclass attribute with its usual mapped
 properties.  The ``__init__`` method created by ``@dataclass`` is left
-intact.   In contrast, the ``@attr.s`` decorator actually removes its
-own class-bound attributes after the decorator runs, so that SQLAlchemy's
-mapping process takes over these attributes without any issue.
+intact. The ``@define`` decorator of attrs_ by default replaces the annotated class
+with a new __slots__ based class, which is not supported. When using the old
+style annotation ``@attr.s`` or using ``define(slots=False)``, the class
+does not get replaced. Furthermore attrs removes its own class-bound attributes
+after the decorator runs, so that SQLAlchemy's mapping process takes over these
+attributes without any issue. Both decorators, ``@attr.s`` and ``@define(slots=False)``
+work with SQLAlchemy.
 
 .. versionadded:: 1.4 Added support for direct mapping of Python dataclasses,
    where the :class:`_orm.Mapper` will now detect attributes that are specific
@@ -438,7 +443,7 @@ came from a mixin that is itself a dataclass, the form would be::
 Example Three - attrs with Imperative Table
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-A mapping using ``@attr.s``, in conjunction with imperative table::
+A mapping using ``@define`` from attrs_, in conjunction with imperative table::
 
     import attr
     from sqlalchemy.orm import registry
@@ -450,7 +455,7 @@ A mapping using ``@attr.s``, in conjunction with imperative table::
 
 
     @mapper_registry.mapped
-    @attr.s
+    @define(slots=False)
     class User:
         __table__ = Table(
             "user",
@@ -460,11 +465,11 @@ A mapping using ``@attr.s``, in conjunction with imperative table::
             Column("fullname", String(50)),
             Column("nickname", String(12)),
         )
-        id = attr.ib()
-        name = attr.ib()
-        fullname = attr.ib()
-        nickname = attr.ib()
-        addresses = attr.ib()
+        id: int
+        name: str
+        fullname: str
+        nickname: str
+        addresses: List[Address]
 
 
     # other classes...