thanks, indeed mysql 8 reorders the keys https://stackoverflow.com/a/48382771
On Wed, Jan 6, 2021, at 11:10 AM, yoch....@gmail.com wrote: > Thank you for your answer. > > I'm using MySQL 8 with pymysql. > > The `data` column has JSON type, and it seems that MySQL is actually > reordering keys. > > > Le mercredi 6 janvier 2021 à 15:31:49 UTC+2, Mike Bayer a écrit : >> __ >> perhaps Python's json encoder does not maintain ordering? I don't know >> either. Can you set echo='debug' on your create_engine() and examine the >> parameters being passed as well as the data being returned? also I'm not >> seeing which database backend or driver you're using which may be >> significant (particularly if its PostgreSQL which has a fully native JSON >> datatype). >> >> >> On Wed, Jan 6, 2021, at 7:39 AM, yoch....@gmail.com wrote: >>> Hi, >>> >>> I have a problem with a custom JSON type, which is not preserving keys >>> order, despite that I'm using python 3.8. >>> >>> Here is the type definition and usage: >>> >>> ``` >>> import json >>> from sqlalchemy import Column, Integer >>> from sqlalchemy.types import TypeDecorator, TEXT >>> from sqlalchemy.ext.mutable import MutableDict >>> >>> class JSONType(TypeDecorator): >>> impl = TEXT >>> >>> def process_bind_param(self, value, dialect): >>> if value is not None: >>> value = json.dumps(value) >>> return value >>> >>> def process_result_value(self, value, dialect): >>> if value is not None: >>> value = json.loads(value) >>> return value >>> >>> JSONDict = MutableDict.as_mutable(JSONType) >>> >>> Base = automap_base() >>> >>> class Picture(Base): >>> __tablename__ = 'picture' >>> id = Column(Integer, primary_key=True) >>> data = Column(JSONDict) >>> ``` >>> >>> When I'm storing values in the data field (values are nested elements of >>> different types), store the picture in database and reload it, the keys >>> order of data dict is not preserved. I'm don't understand why, because the >>> version of python I'm using is supposed to keep the dict insertion order. >>> >>> Have you some idea how to solve that ? The JSON keys order is important for >>> my application. >>> >>> Thank you >>> >>> >>> -- >>> 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/2023e849-37d4-43e5-bd1f-02829474c62bn%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/sqlalchemy/2023e849-37d4-43e5-bd1f-02829474c62bn%40googlegroups.com?utm_medium=email&utm_source=footer>. >> > > -- > 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+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/88cc9e20-834d-4df3-9879-7ceb213f0449n%40googlegroups.com > > <https://groups.google.com/d/msgid/sqlalchemy/88cc9e20-834d-4df3-9879-7ceb213f0449n%40googlegroups.com?utm_medium=email&utm_source=footer>. -- 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+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/bc9122a0-5304-4894-858e-64cc7dcf5506%40www.fastmail.com.
