Refactor database metadata initialization and update JSON download logic for improved clarity and efficiency

db/functions.py

@@ -123,9 +123,9 @@ class settype(object):
                 cursor.execute(text(sql))
         updatesBase.prepare(engine, reflect=True, schema="updates")
         dboBase.prepare(engine, reflect=True, schema="dbo")
-        metadata = sqlalchemy.MetaData("updates")
+        metadata = sqlalchemy.MetaData(schema="updates")
         metadata.reflect(bind=engine)
-        dboMetadata = sqlalchemy.MetaData("dbo")
+        dboMetadata = sqlalchemy.MetaData(schema="dbo")
         dboMetadata.reflect(bind=engine)
         session = Session(engine)
         self.dbengine["engine"] = engine

db/sql.py

@@ -12,27 +12,32 @@ class Dbexec():
     def update_tvupdates(self, engine, available_updates, tablename):
         print('Creating update transaction.')
 
+        # Build batch insert data
         updatelist = [
             {
-                'seriesid': seriesid,
+                'seriesid': str(seriesid),
                 'timestamp': available_updates[seriesid]
             }
             for seriesid in tqdm(
                 available_updates,
-                desc='Updating tvupdates table',
+                desc='Preparing tvupdates records',
                 unit='record'
             )
         ]
 
-        # Commented out code for applying updates for now. Will re-enable later after downloads are verified.
         print('Applying updates to table.')
-        with engine.connect() as conn:
-            conn.execute(text(f"truncate table {tablename}"))
-            for key, value in available_updates.items():
-                seriesid = str(key)
-                timestamp = value
-                conn.execute(text(f"INSERT INTO {tablename} (seriesid, timestamp) VALUES (:seriesid, :timestamp)"), {'seriesid': seriesid, 'timestamp': timestamp})
-            conn.commit()
+        # Use a transactional context; SQLAlchemy Connection.execute accepts
+        # a list of parameter mappings for bulk inserts (it will use the DBAPI
+        # executemany under the hood).
+        with engine.begin() as conn:
+            print(f'Truncating table {tablename} before insert.')
+            conn.execute(text(f"TRUNCATE TABLE {tablename}"))
+            print(f'Inserting {len(updatelist)} records into {tablename}.')
+            if updatelist:
+                conn.execute(
+                    text(f"INSERT INTO {tablename} (seriesid, timestamp) VALUES (:seriesid, :timestamp)"),
+                    updatelist,
+                )
         print('Update of tvupdates table is complete.')
 
     def rawsql_select(self, engine, sqlquery, lprint):