implement primary keys

src/grung/examples.py

@@ -18,7 +18,7 @@ class User(Record):
     def fields(cls):
         return [
             *super().fields(),
-            Field("name"),
+            Field("name", primary_key=True),
             Integer("number", default=0),
             Field("email", unique=True),
             Password("password"),
@@ -33,7 +33,7 @@ class Group(Record):
     def fields(cls):
         return [
             *super().fields(),
-            Field("name", unique=True),
+            Field("name", primary_key=True),
             Collection("members", User),
             Collection("groups", Group),
             BackReference("parent", Group),
@@ -43,8 +43,8 @@ class Group(Record):
 class Album(Record):
     @classmethod
     def fields(cls):
-        return [
-            *super().fields(),
+        inherited = [f for f in super().fields() if f.name != "name"]
+        return inherited + [
             Field("name"),
             Dict("credits"),
             List("tracks"),
@@ -55,8 +55,8 @@ class Album(Record):
 class Artist(User):
     @classmethod
     def fields(cls):
-        return [
-            *super().fields(),
+        inherited = [f for f in super().fields() if f.name != "name"]
+        return inherited + [
             Field("name"),
             RecordDict("albums", Album),
         ]

src/grung/types.py

@@ -14,7 +14,7 @@ from tinydb import TinyDB, where
 
 from grung.exceptions import PointerReferenceError
 
-Metadata = namedtuple("Metadata", ["table", "fields", "backrefs"])
+Metadata = namedtuple("Metadata", ["table", "fields", "backrefs", "primary_key"])
 
 
 @dataclass
@@ -27,6 +27,7 @@ class Field:
     value_type: type = str
     default: str = None
     unique: bool = False
+    primary_key: bool = False
 
     def before_insert(self, value: value_type, db: TinyDB, record: Record) -> None:
         pass
@@ -71,7 +72,7 @@ class List(Field):
     def serialize(self, values: list) -> Dict[(str, str)]:
         return values
 
-    def deserialize(self, values: lsit, db: TinyDB, recurse: bool = False) -> typing.List[str]:
+    def deserialize(self, values: list, db: TinyDB, recurse: bool = False) -> typing.List[str]:
         return values
 
 
@@ -150,8 +151,22 @@ class Record(typing.Dict[(str, Field)]):
     def __init__(self, raw_doc: dict = {}, doc_id: int = None, **params):
         self.doc_id = doc_id
         fields = self.__class__.fields()
+
+        pkey = [field for field in fields if field.primary_key]
+        if len(pkey) > 1:
+            raise Exception(f"Cannnot have more than one primary key: {pkey}")
+        elif pkey:
+            pkey = pkey[0]
+        else:
+            # 1% collision rate at ~2M records
+            pkey = Field("uid", default=nanoid.generate(size=8), primary_key=True)
+            fields.append(pkey)
+
+        pkey.unique = True
+
         self._metadata = Metadata(
             table=self.__class__.__name__,
+            primary_key=pkey.name,
             fields={f.name: f for f in fields},
             backrefs=lambda value_type: (
                 field for field in fields if type(field) == BackReference and field.value_type == value_type
@@ -160,11 +175,8 @@ class Record(typing.Dict[(str, Field)]):
         super().__init__(dict({field.name: field.default for field in fields}, **raw_doc, **params))
 
     @classmethod
-    def fields(self):
-        return [
-            # 1% collision rate at ~2M records
-            Field("uid", default=nanoid.generate(size=8), unique=True)
-        ]
+    def fields(cls):
+        return []
 
     def serialize(self):
         """
@@ -204,7 +216,7 @@ class Record(typing.Dict[(str, Field)]):
     def __getattr__(self, attr_name):
         if attr_name in self:
             return self.get(attr_name)
-        return super().__getattr__(attr_name)
+        raise AttributeError(f"No such attribute: {attr_name}")
 
     def __hash__(self):
         return hash(str(dict(self)))
@@ -242,7 +254,7 @@ class Pointer(Field):
         if value:
             if not value.doc_id:
                 raise PointerReferenceError(value)
-            return f"{value._metadata.table}::{value.uid}"
+            return f"{value._metadata.table}::{value._metadata.primary_key}::{value[value._metadata.primary_key]}"
         return None
 
     @classmethod
@@ -250,11 +262,12 @@ class Pointer(Field):
         if not value:
             return
         elif type(value) == str:
-            pt, puid = value.split("::")
-            if puid:
-                rec = db.table(pt).get(where("uid") == puid, recurse=recurse)
+            table_name, pkey, pval = value.split("::")
+            if pval:
+                table = db.table(table_name)
+                rec = table.get(where(pkey) == pval, recurse=recurse)
                 if not rec:
-                    raise PointerReferenceError(f"Expected a {pt} with uid=={puid} but did not find one!")
+                    raise PointerReferenceError(f"Expected a {table_name} with {pkey}=={pval} but did not find one!")
                 return rec
         return value