Hi There, So I have a bit of an (admittedly unusual) question:
I understand that the Interval type is designed to operate using datetime.timedelta on those SQL engines that natively support the Interval data type (eg PostgreSQL). I also understand that when operating on SQL engines that do *not* natively support the Interval data type, SQLAlchemy coerces datetime.timedelta values to datetime.datetime values relative to the epoch date. Is my understanding so far correct? If so, here is the crux of the situation: given an ORM model class with an Interval attribute, when introspecting either that model class (i.e. the class of the model itself) OR when introspecting an instance of that model class (presumably navigating across InstrumentedAttributes and related Comparators) how can one differentiate between: A) an attribute that is still a native Interval type, B) a “converted” Interval (now represented as a DATETIME type), and C) a native DATETIME type that does not have any relationship to intervals I’m almost certain there’s a mechanism to do this differentiation by navigating the internals, but I'm having trouble putting my finger on how best to accomplish this. My overall objective is to use this differentiation to do appropriate datetime / timedelta arithmetic and conversion based on whether the timedelta is to be persisted to the DB as a native Interval type, or as a datetime relative to the epoch time. Any help or guidance would be much appreciated! All the best, Chris Sent from my iPhone -- 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/CACng_W8AwxAZp1ODeBBTsh%2B1v0hRcet%2Bw6cvdOmsfxwp8WRSLw%40mail.gmail.com.
