flesh out general Collector/Mapper interaction

co3/co3.py

@@ -9,6 +9,7 @@ managing hierarchical document relations, format conversions, and syntactical co
 
 import inspect
 import logging
+from collections import defaultdict
 from functools import wraps, partial
 
 #from localsys.db.schema import tables
@@ -40,6 +41,17 @@ def collate(action_key, action_groups=None):
 class FormatRegistryMeta(type):
     def __new__(cls, name, bases, attrs):
         action_registry = {}
+        group_registry  = defaultdict(list)
+
+        def register_action(method):
+            nonlocal action_registry, group_registry
+
+            if hasattr(method, '_action_data'):
+                action_key, action_groups = method._action_data
+                action_registry[action_key] = (method, action_groups)
+
+                for action_group in action_groups:
+                    group_registry[action_group].append(action_key)
 
         # add registered superclass methods; iterate over bases (usually just one), then
         # that base's chain down (reversed), then methods from each subclass
@@ -47,18 +59,15 @@ class FormatRegistryMeta(type):
             for _class in reversed(base.mro()):
                 methods = inspect.getmembers(_class, predicate=inspect.isfunction)
                 for _, method in methods:
-                    if hasattr(method, '_action_data'):
+                    register_action(method)
-                        action_key, action_groups = method._action_data
-                        action_registry[action_key] = (method, action_groups)
 
         # add final registered formats for the current class, overwriting any found in
         # superclass chain
         for attr_name, attr_value in attrs.items():
-            if hasattr(attr_value, '_action_data'):
+            register_action(attr_value)
-                action_key, action_groups = attr_value._action_data
-                action_registry[action_key] = (method, action_groups)
 
-        attrs['action_map'] = action_registry
+        attrs['action_registry'] = action_registry
+        attrs['group_registry']  = group_registry
 
         return super().__new__(cls, name, bases, attrs)
 
@@ -98,11 +107,25 @@ class CO3(metaclass=FormatRegistryMeta):
         '''
         return []
 
+    def collation_attributes(self, action_key, action_group):
+        '''
+        Return "connective" collation component data, possibly dependent on
+        instance-specific attributes and the action arguments. This is typically the
+        auxiliary structure that may be needed to attach to responses from registered
+        `collate` calls to complete inserts.
+
+        Note: this method is primarily used by `Mapper.collect()`, and is called just
+        prior to collector send-off for collation inserts and injected alongside collation
+        data. Common structure in collation components can make this function easy to
+        define, independent of action group for instance.
+        '''
+        return {}
+
     def collate(self, action_key, *action_args, **action_kwargs):
-        if action_key not in self.action_map:
+        if action_key not in self.action_registry:
             logger.debug(f'Collation for {action_key} not supported')
             return None
         else:
-            return self.action_map[action_key](self)
+            return self.action_registry[action_key][0](self)
 
 

co3/collector.py

@@ -29,32 +29,42 @@ from uuid import uuid4
 import sqlalchemy as sa
 
 from co3 import util
+from co3.schema import Schema
 from co3.component import Component
-#from localsys.db.schema import tables
 
 
 logger = logging.getLogger(__name__)
 
 class Collector[C: Component, M: 'Mapper[C]']:
-    def __init__(self):
+    def __init__(self, schema: Schema[C]):
+        self.schema = schema
+
         self._inserts = defaultdict(lambda: defaultdict(list))
 
     @property
     def inserts(self):
         return self._inserts_from_receipts()
 
-    def _inserts_from_receipts(self, receipts=None, pop=False):
+    def _inserts_from_receipts(self, receipts: list=None, pop=False):
+        '''
+        Group up added inserts by Component, often to be used directly for bulk insertion.
+        Optionally provide a list of `receipts` to group up only the corresponding subset of
+        inserts, and `pop` to remove encountered receipts from the internal store.
+        '''
         inserts = defaultdict(list)
         
         if receipts is None:
             receipts = list(self._inserts.keys())
 
         for receipt in receipts:
-            if pop: insert_dict = self._inserts.pop(receipt, {})
+            if pop:
-            else:   insert_dict = self._inserts[receipt]
+                receipt_tuple = self._inserts.pop(receipt, None)
+            else:
+                receipt_tuple = self._inserts.get(receipt, None)
 
-            for table, insert_list in insert_dict.items():
+            if receipt_tuple is not None:
-                inserts[table].extend(insert_list)
+                component, insert_data = receipt_tuple
+                inserts[component].append(insert_data)
 
         return dict(inserts)
 
@@ -62,24 +72,33 @@ class Collector[C: Component, M: 'Mapper[C]']:
         self._inserts = defaultdict(lambda: defaultdict(list))
 
     def _generate_unique_receipt(self):
-        return str(uuid4())
+        receipt = str(uuid4())
+        while receipt in self._inserts:
+            receipt = str(uuid4())
 
-    def add_insert(self, table_name, insert_dict, receipts=None):
+        return receipt
+
+    def add_insert(
+        self,
+        component   : C,
+        insert_data : dict,
+        receipts    : list | None = None,
+    ):
         '''
-        TODO: formalize table_name mapping; at class level provide a `table_map`, or provide
+        Parameters:
-        the table object itself to this method
+            component:   Component from registered schema
+            insert_data: dict with (possibly raw/incomplete) insert data
+            receipts:    optional list to which generated receipt should be appended.
+                         Accommodates the common receipt list aggregation pattern.
         '''
-        if table_name not in tables.table_map:
+        if component not in self.schema:
             #logger.debug(f'Inserts provided for non-existent table {table_name}')
             return None
 
         receipt = self._generate_unique_receipt()
-
+        self._inserts[receipt] = (
-        self._inserts[receipt][table_name].append(
+            component,
-            utils.db.prepare_insert(
+            component.prepare_insert_data(insert_data),
-                tables.table_map[table_name], 
-                insert_dict
-            )
         )
 
         if receipts is not None:

co3/component.py

@@ -14,6 +14,12 @@ class Component[T]:
         self.schema = schema
         schema.add_component(self)
 
+    def __str__(self):
+        return f'<Component ({self.__class__.__name__})> {self.name}'
+
+    def __repr__(self):
+        return f'<Component ({self.__class__.__name__})> {self.name}'
+
     def get_attributes(self):
         raise NotImplementedError
 

co3/components/__init__.py

@@ -3,7 +3,7 @@ from abc import ABCMeta, abstractmethod
 
 import sqlalchemy as sa
 
-from co3.util.types import TableLike
+from co3.util.types import SQLTableLike
 from co3.component import Component
 
 
@@ -54,14 +54,46 @@ class Relation[T](ComposableComponent[T]):
     ):
         return self
 
-class SQLTable(Relation[TableLike]):
+class SQLTable(Relation[SQLTableLike]):
     @classmethod
     def from_table(cls, table: sa.Table, schema: 'SQLSchema'):
         return cls(table.name, table, schema)
 
-    def get_attributes(self):
+    def get_attributes(self) -> tuple:
         return tuple(self.obj.columns)
 
+    def get_column_defaults(self, include_all=True):
+        '''
+        Provide column:default pairs for a provided SQLAlchemy table.
+
+        Parameters:
+            table: SQLAlchemy table
+            include_all: whether to include all columns, even those without explicit defaults
+        '''
+        default_values = {}
+        for column in self.get_attributes():
+            if column.default is not None:
+                default_values[column.name] = column.default.arg
+            elif column.nullable:
+                default_values[column.name] = None
+            else:
+                # assume empty string if include_all and col has no explicit default 
+                # and isn't nullable
+                if include_all and column.name != 'id':
+                    default_values[column.name] = ''
+
+        return default_values
+
+    def prepare_insert_data(self, insert_data: dict) -> dict:
+        '''
+        Modifies insert dictionary with full table column defaults
+        '''
+        insert_dict = self.get_column_defaults()
+        insert_dict.update(
+            { k:v for k,v in insert_data.items() if k in insert_dict }
+        )
+
+        return insert_dict
 
 # key-value stores
 class Dictionary(Relation[dict]):

co3/mapper.py

@@ -11,12 +11,23 @@ mapper = Mapper[sa.Table]()
 
 mapper.attach(
     Type,
-    attributes=TypeTable,
+    attr_comp=TypeTable,
-    collation=CollateTable,
+    coll_comp=CollateTable,
-    collation_groups={
+    coll_groups={
         'name': NameConversions
     }
 )
+
+Development log:
+    - Overruled design decision: Mappers were previously designed to map from a specific
+      CO3 hierarchy to a specific Schema. The intention was to allow only related types to
+      be attached to a single schema, at least under a particular Mapper. The type
+      restriction has since been removed, however, as it isn't particularly well-founded.
+      During `collect()`, a particular instance collects data from both its attributes and
+      its collation actions. It then repeats the same upward for parent types (part of the
+      same type hierarchy), and down to components (often not part of the same type
+      hierarchy). As such, to fully collect from a type, the Mapper needs to leave
+      registration open to various types, not just those part of the same hierarchy.
 '''
 from typing import Callable, Self
 from collections import defaultdict
@@ -32,15 +43,34 @@ class Mapper[C: Component]:
     '''
     Mapper base class for housing schema components and managing relationships between CO3
     types and storage components (of type C).
+
+    Mappers are responsible for two primary tasks:
+
+    1. Attaching CO3 types to database Components from within a single schema
+    2. Facilitating collection of Component-related insertion data from instances of
+       attached CO3 types
+
+    Additionally, the Mapper manages its own Collector and Composer instances. The
+    Collector receives the inserts from `.collect()` calls, and will subsequently be
+    "dropped off" at an appropriate Database's Manager to actually perform the requested
+    inserts (hence why we tie Mappers to Schemas one-to-one). 
+
+    Dev note: the Composer needs reconsideration, or at least its positioning directly in
+    this class. It may be more appropriate to have at the Schema level, or even just
+    dissolved altogether if arbitrary named Components can be attached to schemas.
     '''
     _collector_cls: type[Collector[C, Self]] = Collector[C, Self]
     _composer_cls:  type[Composer[C, Self]]  = Composer[C, Self]
 
-    def __init__(self, co3_root: type[CO3], schema: Schema):
+    def __init__(self, schema: Schema[C]):
-        self.co3_root = co3_root
+        '''
-        self.schema   = schema
+        Parameters:
+            schema: Schema object holding the set of components eligible as attachment
+                    targets for registered CO3 types
+        '''
+        self.schema = schema
 
-        self.collector = self._collector_cls()
+        self.collector = self._collector_cls(schema)
         self.composer  = self._composer_cls()
 
         self.attribute_comps:  dict[type[CO3], C] = {}
@@ -78,12 +108,6 @@ class Mapper[C: Component]:
             coll_groups: storage components for named collation groups; dict mapping group
                          names to components
         '''
-        # check for type compatibility with CO3 root
-        if not issubclass(type_ref, self.co3_root):
-            raise TypeError(
-                f'Type ref {type_ref} not a subclass of Mapper CO3 root {self.co3_root}'
-            )
-
         # check attribute component in registered schema
         attr_comp = self._check_component(attr_comp)
         self.attribute_comps[type_ref] = attr_comp
@@ -100,35 +124,54 @@ class Mapper[C: Component]:
 
             self.collation_groups[type_ref].update(coll_groups)
 
-    def attach_hierarchy(
+    def attach_many(
         self,
-        type_ref: type[CO3],
+        type_list: list[type[CO3]],
-        obj_name_map: Callable[[type[CO3]], str],
+        attr_name_map: Callable[[type[CO3]], str],
+        coll_name_map: Callable[[type[CO3], str|None], str] | None = None,
     ):
-        pass
+        '''
+        Auto-register a set of types to the Mapper's attached Schema. Associations are
+        made from types to both attribute and collation component names, through
+        `attr_name_map` and `coll_name_map`, respectively. Collation targets are inferred
+        through the registered groups in each type.
 
-    def get_connective_data(
+        Parameters:
+            type_ref:      reference to CO3 type
+            attr_name_map: function mapping from types/classes to attribute component names
+                           in the attached Mapper Schema
+            coll_name_map: function mapping from types/classes & action groups to
+                           collation component names in the attached Mapper Schema. `None`
+                           is passed as the action group to retrieve the default
+                           collection target.
+        '''
+        for _type in type_list:
+            attr_comp = attr_name_map(_type)
+            coll_groups = {}
+            for action_group in _type.group_registry:
+                coll_groups[action_group] = coll_name_map(_type, action_group)
+
+            self.attach(_type, attr_comp, coll_groups=coll_groups)
+
+    def get_attribute_comp(
         self,
-        type_instance: CO3,
+        type_ref: type[CO3]
-        action_key,
+    ) -> C | None:
-        action_group=None,
-    ) -> dict:
-        '''
-        Return data relevant for connecting collation entries to primary storage
-        containers. This is typically some combination of the action key and a unique
-        identifier from the target CO3 instance to form a unique key for inserts from
-        actions. This is called just prior to collector send-off for collation inserts and
-        injected alongside collation data.
-        '''
-        return {}
-
-    def get_attribute_comp(self, type_ref: CO3) -> C | None:
         return self.attribute_comps.get(type_ref, None)
 
-    def get_collation_comp(self, type_ref: CO3, group=str | None) -> C | None:
+    def get_collation_comp(
-        return self.collation_group.get(type_ref, {}).get(group, None)
+        self,
+        type_ref: type[CO3],
+        group=str | None
+    ) -> C | None:
+        return self.collation_groups.get(type_ref, {}).get(group, None)
 
-    def collect(self, obj, action_keys=None) -> dict:
+    def collect(
+        self,
+        obj: CO3,
+        action_keys: list[str]=None,
+        action_groups: list[str]=None,
+    ) -> list:
         '''
         Stages inserts up the inheritance chain, and down through components.
 
@@ -166,7 +209,7 @@ class Mapper[C: Component]:
                 if collation_data is None:
                     continue
 
-                _, action_groups = obj.action_map[action_key]
+                _, action_groups = obj.action_registry[action_key]
                 for action_group in action_groups:
                     collation_component = self.get_collation_comp(_cls, group=action_group)
 
@@ -174,9 +217,9 @@ class Mapper[C: Component]:
                         continue
 
                     # gather connective data for collation components
-                    connective_data = self.get_connective_data(_cls, action_key, action_group)
+                    connective_data = obj.collation_attributes(action_key, action_group)
 
-                    collector.add_insert(
+                    self.collector.add_insert(
                         collation_component,
                         {
                             **connective_data,
@@ -186,7 +229,7 @@ class Mapper[C: Component]:
                     )
 
         # handle components
-        for comp in self.components:
+        for comp in [c for c in obj.components if isinstance(c, CO3)]:
             receipts.extend(comp.collect(collector, formats=formats))
 
         return receipts

co3/schema.py

@@ -3,14 +3,19 @@ Schema
 
 Collection of related storage components, often representing the data structure of an
 entire database. Some databases support multiple schemas, however. In general, a Schema
-can wrap up a relevant subset of tables within a single database, so long as
+can wrap up an associated subset of components within a single database, so long as
-`Manager.recreate()` supports creating components in separate calls.
+`Manager.recreate()` supports creating components in separate calls (even if the
+associated database doesn't explicitly support multiple schemas).
 
 Schema objects are used to:
 
 - Semantically group related storage components
 - Tell databases what components to create/remove together
 - Provide target contexts for connected CO3 type systems within Mappers
+
+with particular emphasis on the latter. Mappers associate exactly one CO3 type hierarchy
+with exactly one Schema. This is an intentional point of simplification in the CO3
+operational model.
 '''
 
 from co3.component import Component

co3/util/db.py

@@ -125,18 +125,6 @@ def sa_exec_explicit(engine, stmt, bind_params=None):
             trans.rollback()  # rollback the transaction explicitly
             raise
 
-def prepare_insert(table, value_dict):
-    '''
-    Modifies insert dictionary with full table column defaults
-    '''
-    insert_dict = get_column_defaults(table)
-    #insert_dict.update(value_dict)
-    insert_dict.update(
-        { k:v for k,v in value_dict.items() if k in insert_dict }
-    )
-
-    return insert_dict
-
 def deferred_fkey(target, **kwargs):
     return sa.ForeignKey(
         target,
@@ -152,27 +140,6 @@ def deferred_cd_fkey(target, **kwargs):
     '''
     return deferred_fkey(target, ondelete='CASCADE', **kwargs)
 
-def get_column_defaults(table, include_all=True):
-    '''
-    Provide column:default pairs for a provided SQLAlchemy table.
-
-    Parameters:
-        table: SQLAlchemy table
-        include_all: whether to include all columns, even those without explicit defaults
-    '''
-    default_values = {}
-    for column in table.columns:
-        if column.default is not None:
-            default_values[column.name] = column.default.arg
-        elif column.nullable:
-            default_values[column.name] = None
-        else:
-            # assume empty string if include_all and col has no explicit default 
-            # and isn't nullable
-            if include_all and column.name != 'id':
-                default_values[column.name] = ''
-
-    return default_values
 
 def get_column_names_str_table(engine, table: str):
     col_sql = f'PRAGMA table_info({table});'

co3/util/types.py

@@ -3,4 +3,4 @@ from typing import TypeVar
 import sqlalchemy as sa
 
 
-TableLike = TypeVar('TableLike', bound=sa.Table | sa.Subquery | sa.Join)
+SQLTableLike = TypeVar('SQLTableLike', bound=sa.Table | sa.Subquery | sa.Join)

examples/.ipynb_checkpoints/vegetables-checkpoint.py

@@ -1,9 +1,12 @@
+'''
+just remembered tomatos aren't vegetables. whoops
+'''
 import random
 
 import sqlalchemy as sa
 
 from co3.schemas import SQLSchema
-from co3 import CO3, collate
+from co3 import CO3, collate, Mapper
 from co3 import util
 
 
@@ -20,6 +23,12 @@ class Tomato(Vegetable):
     @property
     def attributes(self):
         return vars(self)
+        
+    def collation_attributes(self, action_key, action_grounp):
+        return {
+            'name': self.name,
+            'state': action_key,
+        }
 
     @collate('ripe', action_groups=['aging'])
     def ripen(self):
@@ -39,42 +48,58 @@ class Tomato(Vegetable):
             'pieces': random.randint(2, 12)
         }
 
+type_list = [Vegetable, Tomato]
+
 '''
 VEGETABLE
 |
 TOMATO -- AGING
        |
        -- COOKING
+
+Note: foreign keys need to represent values that could be known by objects _without_ first interacting
+with a DB. This is slightly non-standard, given how common it is to depend on another table's integer ID
+(typically a value assigned by the DB using an autoincrement, for example, and not specified explicitly 
+within the insertion body). As a result, SQLTable components need to be able to operate by another unique
+key when expected to connect to other tables in the hierarchy. Below we use `name` with a UNIQUE constraint
+for this purpose. Note that having an integer `id` is still perfectly okay so that a table can manage
+uniqueness of its own rows by default.
 '''
 metadata = sa.MetaData()
 vegetable_table = sa.Table(
     'vegetable',
     metadata,
     sa.Column('id',    sa.Integer, primary_key=True),
-    sa.Column('name',  sa.String),
+    sa.Column('name',  sa.String, unique=True),
+    
     sa.Column('color', sa.String),
 )
 tomato_table = sa.Table(
     'tomato',
     metadata,
     sa.Column('id',   sa.Integer, primary_key=True),
-    sa.Column('vegetable_id',   sa.Integer, util.db.deferred_cd_fkey('vegetables.id')),
+    sa.Column('name', sa.String, util.db.deferred_cd_fkey('vegetable.name'), unique=True),
+    
     sa.Column('radius', sa.Integer),
 )
 tomato_aging_table = sa.Table(
     'tomato_aging_states',
     metadata,
     sa.Column('id',   sa.Integer, primary_key=True),
-    sa.Column('vegetable_id',   sa.Integer, util.db.deferred_cd_fkey('vegetables.id')),
+    sa.Column('name', sa.String, util.db.deferred_cd_fkey('tomato.name'), unique=True),
+    
     sa.Column('state', sa.String),
-    sa.Column('age', sa.Integer),
+    sa.Column('age',   sa.Integer),
 )
 tomato_cooking_table = sa.Table(
     'tomato_cooking_states',
     metadata,
     sa.Column('id',   sa.Integer, primary_key=True),
-    sa.Column('vegetable_id',   sa.Integer, util.db.deferred_cd_fkey('vegetables.id')),
+    sa.Column('name', sa.String, util.db.deferred_cd_fkey('tomato.name'), unique=True),
-    sa.Column('state', sa.String),
+    
+    sa.Column('state',  sa.String),
     sa.Column('pieces', sa.Integer),
 )
-vegetable_schema = SQLSchema.from_metadata(metadata)
+vegetable_schema = SQLSchema.from_metadata(metadata)
+vegetable_mapper = Mapper(vegetable_schema)
+

examples/mapper.ipynb

@@ -16,8 +16,6 @@
     }
    ],
    "source": [
-    "from co3 import Mapper\n",
-    "\n",
     "import vegetables"
    ]
   },
@@ -31,13 +29,38 @@
     "- Need connective function (type to collation) and attribute map. Do we need to this with a subclass? If a func is passed in on init, I can type it appropriately I guess `Callable[[type[CO3],str,str|None],dict]`"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "ef733715-bb75-4263-b216-45e778a06b21",
+   "metadata": {},
+   "source": [
+    "## Usage\n",
+    "The Mapper's primary job is to associate class hierarchies with database components. This can be done in a few ways:\n",
+    "\n",
+    "1. Manually attaching a type reference to a Component\n",
+    "2. Attaching a type reference to a Component's name as registered in a schema\n",
+    "3. Automatically register the CO3 heirarchy to matching schema component names (through transformation)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "d2672422-3596-4eab-ac44-5da617f74b80",
+   "metadata": {
+    "jp-MarkdownHeadingCollapsed": true
+   },
+   "source": [
+    "## Explicit example steps"
+   ]
+  },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 2,
    "id": "7d80f7b9-7458-4ad4-8c1a-3ea56e796b4e",
    "metadata": {},
    "outputs": [],
    "source": [
+    "from co3 import Mapper\n",
+    "\n",
     "vegetable_mapper = Mapper(\n",
     "    vegetables.Vegetable,\n",
     "    vegetables.vegetable_schema\n",
@@ -46,21 +69,34 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 3,
    "id": "d24d31b4-c4a6-4a1e-8bea-c44378aadfdd",
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'\\nvegetable_mapper.attach(\\n    vegetables.Vegetable,\\n    vegetables.vegetable_table,\\n)\\n'"
+      ]
+     },
+     "execution_count": 3,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "# not valid; tables need to be wrapped in CO3 Components\n",
+    "'''\n",
     "vegetable_mapper.attach(\n",
     "    vegetables.Vegetable,\n",
     "    vegetables.vegetable_table,\n",
-    ")"
+    ")\n",
+    "'''"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": 4,
    "id": "f9408562-bf50-4522-909c-318557f85948",
    "metadata": {},
    "outputs": [],
@@ -78,7 +114,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": 5,
    "id": "05fdd404-87ee-4187-832f-2305272758ae",
    "metadata": {},
    "outputs": [],
@@ -96,21 +132,43 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 6,
    "id": "e9b6af49-a69d-41cc-beae-1b6f171cd2f5",
    "metadata": {},
    "outputs": [],
    "source": [
     "# attach entire type hierarchy w/ type->name map\n",
     "vegetable_mapper.attach_hierarchy(\n",
-    "# this might make more sense during init\n",
+    "    # this might make more sense during init\n",
-    "    lambda x:x.__name__.lower())\n",
+    "    vegetables.Vegetable,\n",
+    "    lambda x:x.__name__.lower()\n",
     ")"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": 9,
+   "id": "0fb45a86-5c9b-41b1-a3ab-5691444f175e",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "<co3.components.SQLTable at 0x7f2012b23f80>"
+      ]
+     },
+     "execution_count": 9,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "vegetable_mapper.get_collation_comp(vegetables.Tomato, 'cooking')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
    "id": "2e4336ab-5b5f-484d-815d-164d4b6f40a0",
    "metadata": {},
    "outputs": [
@@ -118,16 +176,16 @@
      "data": {
       "text/plain": [
        "{'co3_root': vegetables.Vegetable,\n",
-       " 'schema': <co3.schemas.SQLSchema at 0x74ac03f5c8c0>,\n",
+       " 'schema': <co3.schemas.SQLSchema at 0x732074224aa0>,\n",
-       " 'collector': <co3.collector.Collector at 0x74ac0357ae70>,\n",
+       " 'collector': <co3.collector.Collector at 0x7320757da120>,\n",
-       " 'composer': <co3.composer.Composer at 0x74ac0357a4b0>,\n",
+       " 'composer': <co3.composer.Composer at 0x7320757da9c0>,\n",
-       " 'attribute_comps': {vegetables.Tomato: <co3.components.SQLTable at 0x74ac09d4a720>},\n",
+       " 'attribute_comps': {vegetables.Tomato: <co3.components.SQLTable at 0x732074224cb0>},\n",
        " 'collation_groups': defaultdict(dict,\n",
-       "             {vegetables.Tomato: {'aging': <co3.components.SQLTable at 0x74ac03f5cad0>,\n",
+       "             {vegetables.Tomato: {'aging': <co3.components.SQLTable at 0x732074224ce0>,\n",
-       "               'cooking': <co3.components.SQLTable at 0x74ac03f5cb00>}})}"
+       "               'cooking': <co3.components.SQLTable at 0x732074224d10>}})}"
       ]
      },
-     "execution_count": 9,
+     "execution_count": 7,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -137,40 +195,187 @@
    ]
   },
   {
-   "cell_type": "code",
+   "cell_type": "markdown",
-   "execution_count": 10,
+   "id": "47859e25-b803-4459-a581-f10bbcfac716",
-   "id": "c16786d4-0b71-42d9-97f7-7893c542104e",
    "metadata": {},
-   "outputs": [],
    "source": [
-    "tomato = vegetables.Tomato('t1', 5)"
+    "## Holistic attachment"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 11,
+   "execution_count": 2,
-   "id": "884d6753-c763-4e71-824a-711436e203e1",
+   "id": "70c9baed-b870-4021-8949-9b713d863de6",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def attr_name_map(cls):\n",
+    "    return f'{cls.__name__.lower()}'\n",
+    "\n",
+    "def coll_name_map(cls, action_group):\n",
+    "    return f'{cls.__name__.lower()}_{action_group}_states'\n",
+    "\n",
+    "vegetables.vegetable_mapper.attach_many(\n",
+    "    vegetables.type_list,\n",
+    "    attr_name_map,\n",
+    "    coll_name_map,\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "c16786d4-0b71-42d9-97f7-7893c542104e",
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "<vegetables.Tomato at 0x74ac082bacc0>"
+       "{'age': 4}"
       ]
      },
-     "execution_count": 11,
+     "execution_count": 3,
      "metadata": {},
      "output_type": "execute_result"
     }
    ],
    "source": [
-    "tomato"
+    "# create new CO3 descendant\n",
+    "tomato = vegetables.Tomato('t1', 5)\n",
+    "\n",
+    "# test a register collation action\n",
+    "tomato.collate('ripe')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "d7fa94ca-3ecd-4ee3-b0dc-f3b2b65ee47c",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "<Component (SQLTable)> tomato"
+      ]
+     },
+     "execution_count": 4,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "vegetables.vegetable_mapper.get_attribute_comp(vegetables.Tomato)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "1adc3bc5-957f-4b5a-bc2c-2d172675826d",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{'schema': <co3.schemas.SQLSchema at 0x7ab568224e60>,\n",
+       " 'collector': <co3.collector.Collector at 0x7ab568225190>,\n",
+       " 'composer': <co3.composer.Composer at 0x7ab5682251c0>,\n",
+       " 'attribute_comps': {vegetables.Vegetable: <Component (SQLTable)> vegetable,\n",
+       "  vegetables.Tomato: <Component (SQLTable)> tomato},\n",
+       " 'collation_groups': defaultdict(dict,\n",
+       "             {vegetables.Vegetable: {},\n",
+       "              vegetables.Tomato: {'aging': <Component (SQLTable)> tomato_aging_states,\n",
+       "               'cooking': <Component (SQLTable)> tomato_cooking_states}})}"
+      ]
+     },
+     "execution_count": 5,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "vars(vegetables.vegetable_mapper)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "id": "f32d1f65-9b1d-4600-b396-8551fbd1fcf7",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "['3bf42abc-8a12-452f-baf6-38a05fc5d420',\n",
+       " '271b7b84-846e-4d1d-87f6-bcabc90a7b55',\n",
+       " 'f9fc5d16-c5cb-47a7-9eca-7df8a3ba5d10']"
+      ]
+     },
+     "execution_count": 6,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "vegetables.vegetable_mapper.collect(tomato, ['ripe'])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "id": "380dfbea-90cc-49fc-aef1-ebb342872632",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "defaultdict(<function co3.collector.Collector.__init__.<locals>.<lambda>()>,\n",
+       "            {'3bf42abc-8a12-452f-baf6-38a05fc5d420': (<Component (SQLTable)> vegetable,\n",
+       "              {'name': 't1', 'color': 'red'}),\n",
+       "             '271b7b84-846e-4d1d-87f6-bcabc90a7b55': (<Component (SQLTable)> tomato,\n",
+       "              {'name': 't1', 'radius': 5}),\n",
+       "             'f9fc5d16-c5cb-47a7-9eca-7df8a3ba5d10': (<Component (SQLTable)> tomato_aging_states,\n",
+       "              {'name': 't1', 'state': 'ripe', 'age': 1})})"
+      ]
+     },
+     "execution_count": 7,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "vegetables.vegetable_mapper.collector._inserts"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "id": "905bb2a9-9c22-4187-be15-3dd32d206e26",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{<Component (SQLTable)> vegetable: [{'name': 't1', 'color': 'red'}],\n",
+       " <Component (SQLTable)> tomato: [{'name': 't1', 'radius': 5}],\n",
+       " <Component (SQLTable)> tomato_aging_states: [{'name': 't1',\n",
+       "   'state': 'ripe',\n",
+       "   'age': 1}]}"
+      ]
+     },
+     "execution_count": 8,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "vegetables.vegetable_mapper.collector.inserts"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "137d0bf1-940d-448c-91e9-01e7fc4f31b4",
+   "id": "d166b9af-e3ba-4750-9dcb-d8d4e08fe4d3",
    "metadata": {},
    "outputs": [],
    "source": []

examples/vegetables.py

@@ -1,9 +1,12 @@
+'''
+just remembered tomatos aren't vegetables. whoops
+'''
 import random
 
 import sqlalchemy as sa
 
 from co3.schemas import SQLSchema
-from co3 import CO3, collate
+from co3 import CO3, collate, Mapper
 from co3 import util
 
 
@@ -20,6 +23,12 @@ class Tomato(Vegetable):
     @property
     def attributes(self):
         return vars(self)
+        
+    def collation_attributes(self, action_key, action_grounp):
+        return {
+            'name': self.name,
+            'state': action_key,
+        }
 
     @collate('ripe', action_groups=['aging'])
     def ripen(self):
@@ -39,42 +48,58 @@ class Tomato(Vegetable):
             'pieces': random.randint(2, 12)
         }
 
+type_list = [Vegetable, Tomato]
+
 '''
 VEGETABLE
 |
 TOMATO -- AGING
        |
        -- COOKING
+
+Note: foreign keys need to represent values that could be known by objects _without_ first interacting
+with a DB. This is slightly non-standard, given how common it is to depend on another table's integer ID
+(typically a value assigned by the DB using an autoincrement, for example, and not specified explicitly 
+within the insertion body). As a result, SQLTable components need to be able to operate by another unique
+key when expected to connect to other tables in the hierarchy. Below we use `name` with a UNIQUE constraint
+for this purpose. Note that having an integer `id` is still perfectly okay so that a table can manage
+uniqueness of its own rows by default.
 '''
 metadata = sa.MetaData()
 vegetable_table = sa.Table(
     'vegetable',
     metadata,
     sa.Column('id',    sa.Integer, primary_key=True),
-    sa.Column('name',  sa.String),
+    sa.Column('name',  sa.String, unique=True),
+    
     sa.Column('color', sa.String),
 )
 tomato_table = sa.Table(
     'tomato',
     metadata,
     sa.Column('id',   sa.Integer, primary_key=True),
-    sa.Column('vegetable_id',   sa.Integer, util.db.deferred_cd_fkey('vegetables.id')),
+    sa.Column('name', sa.String, util.db.deferred_cd_fkey('vegetable.name'), unique=True),
+    
     sa.Column('radius', sa.Integer),
 )
 tomato_aging_table = sa.Table(
     'tomato_aging_states',
     metadata,
     sa.Column('id',   sa.Integer, primary_key=True),
-    sa.Column('vegetable_id',   sa.Integer, util.db.deferred_cd_fkey('vegetables.id')),
+    sa.Column('name', sa.String, util.db.deferred_cd_fkey('tomato.name'), unique=True),
+    
     sa.Column('state', sa.String),
-    sa.Column('age', sa.Integer),
+    sa.Column('age',   sa.Integer),
 )
 tomato_cooking_table = sa.Table(
     'tomato_cooking_states',
     metadata,
     sa.Column('id',   sa.Integer, primary_key=True),
-    sa.Column('vegetable_id',   sa.Integer, util.db.deferred_cd_fkey('vegetables.id')),
+    sa.Column('name', sa.String, util.db.deferred_cd_fkey('tomato.name'), unique=True),
-    sa.Column('state', sa.String),
+    
+    sa.Column('state',  sa.String),
     sa.Column('pieces', sa.Integer),
 )
-vegetable_schema = SQLSchema.from_metadata(metadata)
+vegetable_schema = SQLSchema.from_metadata(metadata)
+vegetable_mapper = Mapper(vegetable_schema)
+