howiezhao commented on PR #1292:
URL:
https://github.com/apache/cassandra-python-driver/pull/1292#issuecomment-4387923680
> Would prefer something more concise, maybe something like...
>
> `.. warning::
>
> **Avoid "Round-Tripping" data using string formatting.**
>
> Never use f-strings or `%` to insert data—especially driver-returned
collections (maps, sets, lists)—back into a CQL query.
>
> **The Gotcha:** The driver's collection objects use Python's `repr()`
formatting for nested values. This automatically doubles backslashes (e.g., `\`
becomes `\\`). Because CQL does not use backslashes as escape characters,
Cassandra will store those extra backslashes literally, **corrupting your
data.**
>
> **The Fix:** Always use **prepared statements**. They transmit data in a
binary format that bypasses Python's string serialization entirely.
>
> .. code-block:: python
>
> ```
> # BAD: f-strings cause double-escaping/corruption
> session.execute(f"UPDATE t SET my_map={row.my_map} WHERE id=1")
>
> # GOOD: Prepared statements preserve data exactly
> stmt = session.prepare("UPDATE t SET my_map=? WHERE id=1")
> session.execute(stmt, [row.my_map])`
> ```
Hi @bschoening good suggestion, updated
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