X-Git-Url: https://plomlompom.com/repos/berlin_corona.txt?a=blobdiff_plain;f=plomtask%2Fdb.py;h=982ddfe3b96915d4ffc8bd8d4bce264671c09069;hb=10af8a54a17047a4554d4b8d051a238271c74906;hp=34b5887c0204532ea6a32ade0eed6ccea92fbbaa;hpb=704c00a101fc1922158a3a71a043562d34b696ad;p=plomtask

diff --git a/plomtask/db.py b/plomtask/db.py
index 34b5887..982ddfe 100644
--- a/plomtask/db.py
+++ b/plomtask/db.py
@@ -130,6 +130,23 @@ class BaseModel(Generic[BaseModelId]):
             raise HandledException(msg)
         self.id_ = id_
 
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, self.__class__):
+            return False
+        to_hash_me = tuple([self.id_] +
+                           [getattr(self, name) for name in self.to_save])
+        to_hash_other = tuple([other.id_] +
+                              [getattr(other, name) for name in other.to_save])
+        return hash(to_hash_me) == hash(to_hash_other)
+
+    def __lt__(self, other: Any) -> bool:
+        if not isinstance(other, self.__class__):
+            msg = 'cannot compare to object of different class'
+            raise HandledException(msg)
+        assert isinstance(self.id_, int)
+        assert isinstance(other.id_, int)
+        return self.id_ < other.id_
+
     @classmethod
     def get_cached(cls: type[BaseModelInstance],
                    id_: BaseModelId) -> BaseModelInstance | None:
@@ -179,27 +196,26 @@ class BaseModel(Generic[BaseModelId]):
         obj.cache()
         return obj
 
-    @classmethod
-    def _by_id(cls, db_conn: DatabaseConnection,
-               id_: BaseModelId) -> Self | None:
-        """Return instance found by ID, or None, and if from cache or not."""
-        obj = cls.get_cached(id_)
-        if not obj:
-            for row in db_conn.row_where(cls.table_name, 'id', id_):
-                obj = cls.from_table_row(db_conn, row)
-                obj.cache()
-                break
-        return obj
-
     @classmethod
     def by_id(cls, db_conn: DatabaseConnection,
               id_: BaseModelId | None,
               # pylint: disable=unused-argument
               create: bool = False) -> Self:
-        """Retrieve by id_, on failure throw NotFoundException."""
+        """Retrieve by id_, on failure throw NotFoundException.
+
+        First try to get from cls.cache_, only then check DB; if found,
+        put into cache.
+
+        If create=True, make anew (but do not cache yet).
+        """
         obj = None
         if id_ is not None:
-            obj = cls._by_id(db_conn, id_)
+            obj = cls.get_cached(id_)
+            if not obj:
+                for row in db_conn.row_where(cls.table_name, 'id', id_):
+                    obj = cls.from_table_row(db_conn, row)
+                    obj.cache()
+                    break
         if obj:
             return obj
         if create:
@@ -210,7 +226,13 @@ class BaseModel(Generic[BaseModelId]):
     @classmethod
     def all(cls: type[BaseModelInstance],
             db_conn: DatabaseConnection) -> list[BaseModelInstance]:
-        """Collect all objects of class."""
+        """Collect all objects of class into list.
+
+        Note that this primarily returns the contents of the cache, and only
+        _expands_ that by additional findings in the DB. This assumes the
+        cache is always instantly cleaned of any items that would be removed
+        from the DB.
+        """
         items: dict[BaseModelId, BaseModelInstance] = {}
         for k, v in cls.get_cache().items():
             assert isinstance(v, cls)
@@ -223,16 +245,6 @@ class BaseModel(Generic[BaseModelId]):
                 items[item.id_] = item
         return list(items.values())
 
-    def __eq__(self, other: object) -> bool:
-        if not isinstance(other, self.__class__):
-            msg = 'cannot compare to object of different class'
-            raise HandledException(msg)
-        to_hash_me = tuple([self.id_] +
-                           [getattr(self, name) for name in self.to_save])
-        to_hash_other = tuple([other.id_] +
-                              [getattr(other, name) for name in other.to_save])
-        return hash(to_hash_me) == hash(to_hash_other)
-
     def save_core(self, db_conn: DatabaseConnection) -> None:
         """Write bare-bones self (sans connected items), ensuring self.id_.
 
@@ -255,7 +267,8 @@ class BaseModel(Generic[BaseModelId]):
         self.cache()
 
     def remove(self, db_conn: DatabaseConnection) -> None:
-        """Remove from DB."""
-        assert isinstance(self.id_, int | str)
+        """Remove from DB and cache."""
+        if self.id_ is None or self.__class__.get_cached(self.id_) is None:
+            raise HandledException('cannot remove unsaved item')
         self.uncache()
         db_conn.delete_where(self.table_name, 'id', self.id_)