I see. But still I'm struggling to see the real difference between: Node.parent_id = Node.id vs. Node.id = Node.parent_id
Aren't we just switching around sides here? On Thu, Jul 20, 2017 at 4:47 PM, Mike Bayer <mike...@zzzcomputing.com> wrote: > On Thu, Jul 20, 2017 at 1:34 PM, Jinghui Niu <niujing...@gmail.com> wrote: > > I've been studying sqlalchemy's self referential table. I've read the > > documentation many times and still have difficulties understanding the > > concept of remote_side. Could someone please draw a diagram or use an > > analogy to help explain this concept? I think visualizing is a better way > > but anything helps would be appreciated. Thanks. > > > > > > By the way, in my opinion the word remote is a little vague, as it can be > > interpreted from different angles. Like the word left and rigt, it really > > depends on which direction you are facing, my right could be your left. > > > it's more specific than "left" and "right", because if you have: > > Node.relationship(remote_side=something) -> Node > > the "remote_side" refers specifically to the columns that are not > local to the Node that has the .relationship. > > That is: > > Node.col1 > Node.col2 > Node.relationship: > name='foo' > local_side=Node.col1 > remote_side=Node.col2 > > > You then know that: > > query(Node).join(Node.foo, aliased=True) > > will emit the equivalent of: > > SELECT * FROM node JOIN node AS node_remote ON node.col1 = node_remote.col2 > > > > > > > > I'm > > not really confident in this but I would guess chaing the name from > > remote_side to many_side may help? Correct me if I'm wrong here. > > > > -- > > 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 post to this group, send email to sqlalchemy@googlegroups.com. > > Visit this group at https://groups.google.com/group/sqlalchemy. > > For more options, visit https://groups.google.com/d/optout. > > -- > 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 a topic in the > Google Groups "sqlalchemy" group. > To unsubscribe from this topic, visit https://groups.google.com/d/ > topic/sqlalchemy/e68eFOoG3LQ/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > sqlalchemy+unsubscr...@googlegroups.com. > To post to this group, send email to sqlalchemy@googlegroups.com. > Visit this group at https://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. > -- 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 post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
