add explanation why conn.execute is used instead of insert.values

Author: jacadzaca

pandas/io/sql.py

@@ -964,6 +964,10 @@ def _execute_insert_multi(self, conn, keys: list[str], data_iter) -> int:
 
         data = [dict(zip(keys, row)) for row in data_iter]
         stmt = insert(self.table)
+        # conn.execute is used here to ensure compatibility with Oracle.
+        # Using stmt.values(data) would produce a multi row insert that
+        # isn't supported by Oracle.
+        # see: https://docs.sqlalchemy.org/en/20/core/dml.html#sqlalchemy.sql.expression.Insert.values
         result = conn.execute(stmt, data)
         return result.rowcount