Updated __tablename__-setting logic.

alchy/model.py

@@ -11,10 +11,10 @@
 from . import query, events
 from .utils import (
     is_sequence,
-    has_primary_key,
     camelcase_to_underscore,
     get_mapper_class,
     merge_declarative_args,
+    should_set_tablename,
 )
 from ._compat import iteritems
 
@@ -37,12 +37,8 @@ class ModelMeta(DeclarativeMeta):
     or :attr:`ModelBase.__events__`.
     """
     def __new__(mcs, name, bases, dct):
-        # Determine if primary key is defined for dct or any of its bases.
-        base_dcts = [dct] + [base.__dict__ for base in bases]
-
-        if (not dct.get('__tablename__') and
-                dct.get('__table__') is None and
-                any([has_primary_key(base) for base in base_dcts])):
+        # Determine if should set __tablename__.
+        if should_set_tablename(bases, dct):
             # Set to underscore version of class name.
             dct['__tablename__'] = camelcase_to_underscore(name)
 
@@ -55,6 +51,7 @@ def __new__(mcs, name, bases, dct):
             dct['__events__'] = {}
 
         if '__bind_key__' not in dct:
+            base_dcts = [dct] + [base.__dict__ for base in bases]
             for base in base_dcts:
                 if '__bind_key__' in base:
                     dct['__bind_key__'] = base['__bind_key__']
@@ -71,8 +68,6 @@ def __init__(cls, name, bases, dct):
 
             events.register(cls, dct)
 
-        base_dcts = [dct] + [base.__dict__ for base in bases]
-
 
 class ModelBase(object):
     """Base class for creating a declarative base for models.

alchy/utils.py

@@ -8,8 +8,9 @@
 from collections import Iterable
 
 from sqlalchemy import Column
+from sqlalchemy.ext.declarative import AbstractConcreteBase
 
-from ._compat import string_types, iteritems, classmethod_func
+from ._compat import string_types, iteritems, itervalues, classmethod_func
 
 
 __all__ = [
@@ -127,3 +128,61 @@ def merge_declarative_args(cls, global_config_key, local_config_key):
     args = unique(args)
 
     return (args, kargs)
+
+
+def should_set_tablename(bases, dct):
+    """Check what values are set by a class and its bases to determine if a
+    tablename should be automatically generated.
+
+    The class and its bases are checked in order of precedence: the class
+    itself then each base in the order they were given at class definition.
+
+    Abstract classes do not generate a tablename, although they may have set
+    or inherited a tablename elsewhere.
+
+    If a class defines a tablename or table, a new one will not be generated.
+    Otherwise, if the class defines a primary key, a new name will be
+    generated.
+
+    This supports:
+
+    * Joined table inheritance without explicitly naming sub-models.
+    * Single table inheritance.
+    * Concrete table inheritance
+    * Inheriting from mixins or abstract models.
+
+    :param bases: base classes of new class
+    :param dct: new class dict
+    :return: True if tablename should be set
+    """
+
+    if '__tablename__' in dct or '__table__' in dct or '__abstract__' in dct:
+        return False
+
+    if has_primary_key(dct):
+        return True
+
+    if '__mapper_args__' in dct:
+        is_concrete = dct.get('__mapper_args__', {}).get('concrete', False)
+    else:
+        is_concrete = dct.get('__global_mapper_args__', {}).get('concrete',
+                                                                False)
+        is_concrete = dct.get('__local_mapper_args__', {}).get('concrete',
+                                                               is_concrete)
+
+    for base in bases:
+        if base is AbstractConcreteBase:
+            return False
+
+        if (not is_concrete) and (hasattr(base, '__tablename__') or
+                                  hasattr(base, '__table__')):
+            return False
+
+        for name in dir(base):
+            if not (name in ('query') or
+                    (name.startswith('__') and name.endswith('__'))):
+                attr = getattr(base, name)
+                if getattr(attr, 'primary_key', False):
+                    return True
+
+    return False

tests/test_model.py

@@ -1,9 +1,9 @@
 
-import sqlalchemy
-from sqlalchemy import orm, Column, types, inspect, Index
+from sqlalchemy import orm, Column, types, inspect, Index, ForeignKey
 from sqlalchemy.orm.exc import UnmappedClassError
+from sqlalchemy.ext.declarative import ConcreteBase, AbstractConcreteBase
 
-from alchy import model, query, manager, events
+from alchy import query
 
 from .base import TestQueryBase
 from . import fixtures
@@ -540,3 +540,78 @@ def test_is_modified(self):
 
         record.refresh()
         self.assertEqual(record.is_modified(), False)
+
+    def test_should_set_tablename(self):
+        class AAA(Model):
+            __abstract__ = True
+            idx = Column(types.Integer(), primary_key=True)
+
+        self.assertEqual(hasattr(AAA, '__tablename__'), False)
+
+        class BBB(AAA):
+            __abstract__ = True
+            b_int = Column(types.Integer())
+
+        self.assertEqual(hasattr(BBB, '__tablename__'), False)
+
+        class CCC(BBB):
+            c_int = Column(types.Integer())
+
+        self.assertEqual(getattr(CCC, '__tablename__'), 'ccc')
+
+        # Joined table inheritance
+        class DDD(CCC):
+            idx = Column(types.Integer(), ForeignKey(CCC.idx),
+                         primary_key=True)
+            d_int = Column(types.Integer())
+
+        self.assertEqual(getattr(DDD, '__tablename__'), 'ddd')
+
+        # Single table inheritance
+        class EEE(BBB):
+            idx = Column(types.Integer(), primary_key=True)
+            e_str = Column(types.String())
+            __global_mapper_args__ = {'polymorphic_on': e_str}
+
+        self.assertEqual(getattr(EEE, '__tablename__'), 'eee')
+
+        class FFF(EEE):
+            f_int = Column(types.Integer())
+            __local_mapper_args__ = {'polymorphic_identity': 'eee_subtype_fff'}
+
+        self.assertEqual(getattr(FFF, '__tablename__'), 'eee')
+
+        # Concrete table inheritance
+        class GGG(CCC):
+            idx = Column(types.Integer(), primary_key=True)
+            g_int = Column(types.Integer())
+            __local_mapper_args__ = {'concrete': True}
+
+        self.assertEqual(getattr(GGG, '__tablename__'), 'ggg')
+
+        # Concrete table inheritance - using ConcreteBase
+        class HHH(ConcreteBase, BBB):
+            h_int = Column(types.Integer())
+            __local_mapper_args__ = {'polymorphic_on': h_int, 'concrete': True}
+
+        self.assertEqual(getattr(HHH, '__tablename__'), 'hhh')
+
+        class III(HHH):
+            idx = Column(types.Integer(), primary_key=True)
+            i_int = Column(types.Integer())
+            __mapper_args__ = {'polymorphic_identity': 2, 'concrete': True}
+
+        self.assertEqual(getattr(III, '__tablename__'), 'iii')
+
+        # Concrete table inheritance - using AbstractConcreteBase
+        class JJJ(AbstractConcreteBase, BBB):
+            pass
+
+        self.assertEqual(hasattr(JJJ, '__tablename__'), False)
+
+        class KKK(JJJ):
+            idx = Column(types.Integer(), primary_key=True)
+            k_int = Column(types.Integer())
+            __mapper_args__ = {'polymorphic_identity': 2, 'concrete': True}
+
+        self.assertEqual(getattr(KKK, '__tablename__'), 'kkk')