X-Git-Url: https://plomlompom.com/repos/%7B%7B%20web_path%20%7D%7D/decks/%7B%7Bdeck_id%7D%7D/cards/%7B%7B%20card_id%20%7D%7D/delete?a=blobdiff_plain;f=plomtask%2Fdb.py;h=abd8f6181db946b357902a0ec851f51919f37344;hb=5a5d713ce0b223ab2f6ef34c15bb82b614bdda98;hp=dfb388b7ec6ed9317f19a788336025a96e4c745e;hpb=c5fab0b28785bb8f3a8e2b8e455fd679cfe83d25;p=plomtask

diff --git a/plomtask/db.py b/plomtask/db.py
index dfb388b..abd8f61 100644
--- a/plomtask/db.py
+++ b/plomtask/db.py
@@ -1,7 +1,7 @@
 """Database management."""
 from os.path import isfile
 from difflib import Differ
-from sqlite3 import connect as sql_connect, Cursor
+from sqlite3 import connect as sql_connect, Cursor, Row
 from typing import Any, Dict
 from plomtask.exceptions import HandledException
 
@@ -73,6 +73,36 @@ class BaseModel:
     table_name = ''
     to_save: list[str] = []
     id_: None | int | str
+    id_type: type[Any] = int
+
+    @classmethod
+    def from_table_row(cls, db_conn: DatabaseConnection,
+                       row: Row | list[Any]) -> Any:
+        """Make from DB row, write to DB cache."""
+        obj = cls(*row)
+        assert isinstance(obj.id_, cls.id_type)
+        cache = getattr(db_conn, f'cached_{cls.table_name}')
+        cache[obj.id_] = obj
+        return obj
+
+    @classmethod
+    def _by_id(cls,
+               db_conn: DatabaseConnection,
+               id_: int | str) -> tuple[Any, bool]:
+        """Return instance found by ID, or None, and if from cache or not."""
+        from_cache = False
+        obj = None
+        cache = getattr(db_conn, f'cached_{cls.table_name}')
+        if id_ in cache.keys():
+            obj = cache[id_]
+            from_cache = True
+        else:
+            for row in db_conn.exec(f'SELECT * FROM {cls.table_name} '
+                                    'WHERE id = ?', (id_,)):
+                obj = cls.from_table_row(db_conn, row)
+                cache[id_] = obj
+                break
+        return obj, from_cache
 
     def set_int_id(self, id_: int | None) -> None:
         """Set id_ if >= 1 or None, else fail."""