> but make it hard to make changes to the data structure later. What happens if that int should actually be a float? Now you have to write a migration that makes fundamental changes to the structure of the data and hope there are no negative side effects.
This is often stated, but it's not true. RDBMS make it easier to make changes to the data structure precisely because you only have to write migration and after that you are guaranteed to only ever get the data out of database in the new format. Which means your application code doesn't accumulate the cruft of dealing with two possible database data formats.
I strongly disagree that this pattern makes it easier to make changes. It makes it easier to use the data (because you know this data will always be this type), but changing the data is harder than if it did not enforce a type.
I'm not arguing that un-typed data in a DB is easy to use or a good idea, just that it's harder to change the structure of RDBMS if you didn't plan properly from the beginning.
Basically: I think data is hard and I wish there were better tools for interacting with it.
This is often stated, but it's not true. RDBMS make it easier to make changes to the data structure precisely because you only have to write migration and after that you are guaranteed to only ever get the data out of database in the new format. Which means your application code doesn't accumulate the cruft of dealing with two possible database data formats.