Small logical mistake on schema applying.

SlidingSqlite.py

@@ -187,7 +187,7 @@ class SlidingSQLite:
     def _get_connection(self, db_file: str) -> sqlite3.Connection:
         """
         Get a connection to the specified database file.
-        Reuses existing connections when possible.
+        Reuses existing connections when possible and applies schema only if needed.
 
         Args:
             db_file: Path to the database file
@@ -214,8 +214,30 @@ class SlidingSQLite:
                     )
                     conn.execute("PRAGMA journal_mode=WAL;")
                     conn.execute("PRAGMA busy_timeout=5000;")
-                    if db_file != self._get_metadata_db():
-                        conn.executescript(self.schema)
+                    
+                    # Only apply schema if the database is new
+                    if db_file != self._get_metadata_db() and os.path.exists(db_file):
+                        # Check if schema is already applied by testing for a known table
+                        try:
+                            conn.execute("SELECT 1 FROM node_auth LIMIT 1")
+                        except sqlite3.Error:
+                            # Schema not applied yet, apply it
+                            try:
+                                conn.executescript(self.schema)
+                                conn.commit()
+                            except sqlite3.Error as e:
+                                logging.error(f"Failed to apply schema to {db_file}: {e}")
+                                conn.close()
+                                raise DatabaseError(f"Failed to apply schema to {db_file}: {e}")
+                    elif db_file != self._get_metadata_db():
+                        # New file, apply schema
+                        try:
+                            conn.executescript(self.schema)
+                            conn.commit()
+                        except sqlite3.Error as e:
+                            logging.error(f"Failed to apply schema to new {db_file}: {e}")
+                            conn.close()
+                            raise DatabaseError(f"Failed to apply schema to {db_file}: {e}")
 
                     self.connections[db_file] = conn
                 except sqlite3.Error as e:
@@ -262,15 +284,15 @@ class SlidingSQLite:
                         "SELECT id FROM metadata WHERE db_file = ?", (current_db,)
                     )
                     existing = cursor.fetchone()
-                    if existing:
-                        logging.debug(f"Database {current_db} already registered")
-                    else:
+                    if not existing:
                         conn.execute(
                             "INSERT OR IGNORE INTO metadata (db_file, start_time, end_time) VALUES (?, ?, ?)",
                             (current_db, interval_start, interval_end),
                         )
                         conn.commit()
                         logging.debug(f"Registered new database: {current_db}")
+                    else:
+                        logging.debug(f"Database {current_db} already registered")
             except sqlite3.Error as e:
                 logging.error(f"Failed to register current database: {e}")
                 # Continue execution as this is not critical