heh. reading the SQLA docs cover to cover is not particularly useful for beginners either... :)
On Mar 22, 2014, at 6:12 PM, Bao Niu <niuba...@gmail.com> wrote: > Hi Michael, > Just a quick line, version table is not something particularly useful for > beginner users, am I right? Thanks. > > > On Sat, Mar 22, 2014 at 2:52 PM, Michael Bayer <mike...@zzzcomputing.com> > wrote: > when you're using an event such as before_flush() to check on > attributes.get_history() so that you can see that a new "version" needs to be > inserted into a version table, you need the old value of the attribute in > order to compare. see the versioned_history example. > > > On Mar 22, 2014, at 4:34 PM, Bao Niu <niuba...@gmail.com> wrote: > >> In the documentation for sqlalchemy.orm.column_property, there is a section >> explaining the *active_history* flag. It is very terse. I think it is very >> useful but just cannot think of a scenario where I would ever want to use >> *previous* value when I'm setting a new value. Could someone use plain >> language to explain it a bit more? Thanks. >> >> (I sometimes find reading SA documentations is like reading Bible, you know >> the content is good for you, but you cannot easily figure out how. Group >> study really helps:) >> >> -- >> 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 http://groups.google.com/group/sqlalchemy. >> For more options, visit https://groups.google.com/d/optout. > > > -- > 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/Yvj8q4fv9oE/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 http://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. > > > -- > 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 http://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. -- 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 http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
