Not on my end ! The openstack code I referred towards is regex based but works very well.
On Sun, Aug 5, 2018, 4:08 PM Kevin Isaac <ke...@zephony.com> wrote: > Any updates to this Michael? I've been researching about this but couldn't > find a better solution than parsing the error message with regex. Would > love to hear if there's a better way of doing this. > > On Saturday, December 20, 2014 at 12:52:49 AM UTC+5:30, Michael Bayer > wrote: >> >> >> >> alchemy1 <veeruk...@hotmail.com> wrote: >> >> I'm using ORM and I've defined a unique constraint on a column, and I >> want to prevent inserting another row with the same value for that column. >> For example if you don't want 2 users with the same name. >> >> One way to prevent it would be to take the provided name and query the >> user table to see if anyone has that name, and if not then insert the >> record. The problem with this is that in between checking for the name and >> inserting the name, someone else could have inserted a record with that >> name. So is there any advantage to doing this? Is there any better way to >> do it? >> >> If not, I suppose you'd want to handle the IntegrityError that SQLAlchemy >> throws when it detects a unique constraint violation. But since >> IntegrityError handles several types of types of violations, would checking >> the string of the error message be the only way to ensure you're handling >> the correct error condition, so that you can put a specific message like "A >> user with that name already exists"? >> >> sqlalchemy.exc.IntegrityError: (IntegrityError) duplicate key value violates >> unique constraint "name_of_constraint" >> >> If so, how can I use metadata to get the name of the particular >> constraint I have in mind, so that I can search for it in the error message >> string? I've tried looking through the MetaData API and have got this far >> but I am stuck. I can't seem to find the constraint name set on the name >> column here. >> >> Base.metadata.tables.user.c.name >> User.name.info >> >> >> yes, the non-standardization of DBAPI errors is something SQLAlchemy as >> yet has not tried to solve, though in very recent releases it has begun to >> provide hooks so that these solutions can be rolled more liberally. The >> way I’ve solved this in Openstack looks like this: >> >> >> https://github.com/openstack/oslo.db/blob/0265aa4e01270b8fc7cab1266b8602e1921c9ddb/oslo/db/sqlalchemy/exc_filters.py#L93 >> >> that regular expression is built upon a larger system that ultimately >> makes use of the SQLAlchemy handle_error() event, which is new in recent >> 0.9 series. You can see that we pull the columns out of the exception >> message itself. >> >> >> >> >> >> -- >> 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 post to this group, send email to sqlal...@googlegroups.com. >> Visit this group at http://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. > -- 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.
