row.Row and dict behavior in 2.0

[mkmo...@gmail.com]

Hello,

It looks like in 2.0 we can no longer treat a row.Row as a dict. I have a few cases where I want to do this, such as when I need to get a list of columns, or when I don't know the column name in advance.

    rows = conn.execute(select(t.c.foo)).fetchall()

    rows[0].keys()  # Not Allowed

    rows[0][some_unknown_column]  # not allowed

If we need to treat it as a dict, are we supposed to be calling:

    rows[0]._asdict()

This works, but the only issue is that our IDEs flag this as accessing a protected member of a class. Is there any alternative?

Thanks and best regards,

Matthew

[Mike Bayer]

you have more options here than previously on how to treat rows, as tuples or mappings, either up front or on a per-row basis.  the new API has been  available as of version 1.4.  Relevant links include:

1. announcement of change and rationale

https://docs.sqlalchemy.org/en/14/changelog/migration_14.html#rowproxy-is-no-longer-a-proxy-is-now-called-row-and-behaves-like-an-enhanced-named-tuple

2. migration guide

https://docs.sqlalchemy.org/en/14/changelog/migration_20.html#result-rows-act-like-named-tuples

3. new tutorial coverage

https://docs.sqlalchemy.org/en/14/tutorial/dbapi_transactions.html#fetching-rows

included is background on how to get mappings from a Row or how to get RowMapping objects from a result up front using result.mappings().

Matthew

--

SQLAlchemy -

The Python SQL Toolkit and Object Relational Mapper

 

http://www.sqlalchemy.org/

 

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description.

---

You received this message because you are subscribed to the Google Groups "sqlalchemy" group.

To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/10721070-ecf9-4438-87dc-a9ff6c13c0dan%40googlegroups.com.

[mkmo...@gmail.com]

Hi Mike,

Thanks. I have a few cases where it is easiest if I have a plain dict instead of a RowMapping. For example RowMapping is immutable, and isn't playing nicely with my json encoder.

What is your preferred method to convert to a plain dict?

    Row._asdict()

    dict(RowMapping.items())

    something else?

Thanks and best regards,

Matthew

[Mike Bayer]

On Thu, Jan 12, 2023, at 1:46 PM, mkmo...@gmail.com wrote:

Hi Mike,

Thanks. I have a few cases where it is easiest if I have a plain dict instead of a RowMapping. For example RowMapping is immutable, and isn't playing nicely with my json encoder.

What is your preferred method to convert to a plain dict?

for row in result.mappings():

    d = dict(row)

should do it

the row was not mutable in 1.4, 1.3, etc. either, what did you do then ?

To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/624b2fdc-1c9d-4c3b-9424-f091b4be529an%40googlegroups.com.

[mkmo...@gmail.com]

Hi Mike,

That's much more concise, thank you.

Previously I have always accessed the  `_asdict()` private member.

Thanks and best regards,

Matthew