Refactor updates of relations tables.

[plomtask] / plomtask / db.py

diff --git a/plomtask/db.py b/plomtask/db.py
index 2cc1d64d54576a46a0b9c7edb513abaa28d4008e..bf633e2c9826f464c690b03b75dfda4a33df7234 100644 (file)
--- a/plomtask/db.py
+++ b/plomtask/db.py
@@ -67,6 +67,20 @@ class DatabaseConnection:
         """Close DB connection."""
         self.conn.close()
 
+    def rewrite_relations(self, table_name: str, key: str, target: int,
+                          rows: list[list[Any]]) -> None:
+        """Rewrite relations in table_name to target, with rows values."""
+        self.exec(f'DELETE FROM {table_name} WHERE {key} = ?', (target,))
+        for row in rows:
+            values = tuple([target] + row)
+            q_marks = self.__class__.q_marks_from_values(values)
+            self.exec(f'INSERT INTO {table_name} VALUES {q_marks}', values)
+
+    @staticmethod
+    def q_marks_from_values(values: tuple[Any]) -> str:
+        """Return placeholder to insert values into SQL code."""
+        return '(' + ','.join(['?'] * len(values)) + ')'
+
 
 class BaseModel:
     """Template for most of the models we use/derive from the DB."""
@@ -76,7 +90,8 @@ class BaseModel:
     id_type: type[Any] = int
 
     @classmethod
-    def from_table_row(cls, db_conn: DatabaseConnection, row: Row) -> Any:
+    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)
@@ -84,6 +99,25 @@ class BaseModel:
         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."""
         if (id_ is not None) and id_ < 1:
@@ -94,11 +128,11 @@ class BaseModel:
     def save_core(self, db_conn: DatabaseConnection,
                   update_with_lastrowid: bool = True) -> None:
         """Write bare-bones self (sans connected items), ensuring self.id_."""
-        q_marks = ','.join(['?'] * (len(self.to_save) + 1))
         values = tuple([self.id_] + [getattr(self, key)
                                      for key in self.to_save])
+        q_marks = DatabaseConnection.q_marks_from_values(values)
         table_name = self.table_name
-        cursor = db_conn.exec(f'REPLACE INTO {table_name} VALUES ({q_marks})',
+        cursor = db_conn.exec(f'REPLACE INTO {table_name} VALUES {q_marks}',
                               values)
         if update_with_lastrowid:
             self.id_ = cursor.lastrowid