Expand the caveat about models in migrations in the rails guide. #7050
Conversation
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I'm not sure if this documentation change is enough to address the issue in #6939. Do you think it would be helpful to be more explicit? |
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This is not informative enough. It might make people think there is some latency for new database fields to be considered, when it's only a simple in memory cache. |
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Good point. Ok, I've tried to expand it at the bottom of the existing section. I initially went overboard with code examples, but I think that it's not important enough to warrant a huge section for itself, I just want to make the point that using models is iffy and can lead to subtle and complicated problems, and that this should be handled with care. I'd be happy to tweak further if you have any good ideas. |
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I feel this is a bit too verbose, but I'm ok to merge. Please either rebase & squash the commits into one, Or make these changes in docrails. Thanks. |
This is an attempt to address issue #6939, where an earlier migration added a column to the database, and a later migration uses a model and references that column. When both migrations were run together with `rake db:migrate` the column information in memory still referenced the old table structure. Running the migrations separately fixed this, as a new connection was then established before referencing the model. Explicitly calling `reset_column_information` is a more reliable workaround.
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Thank you. I've rebased and squashed the commits. |
Expand the caveat about models in migrations in the rails guide.
This is an attempt to address issue #6939, where an earlier migration
added a column to the database, and a later migration uses a model and
references that column.
When both migrations were run together with
rake db:migratethe columninformation in memory still referenced the old table structure.
Running the migrations separately fixed this, as a new connection was
then established before referencing the model. Explicitly calling
reset_column_informationis a more reliable workaround.