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Comment by hackits | Hacker News Reader

Our current manager wants to transition over to NoSQL, as he doesn't see any value having to constantly update JPA Repositories and dependencies when a column is added or removed from the database table.

I recommended that JPA Repositories shouldn't be stored at the lowest level of Maven jar package's eg... we have a very deep nested Maven pom dependencies (about 6 layers deep) of which the JPA repositories are defined in the lowest of lowest levels. Granted I gave references to research papers from Google that JPA Repositories and Hibernate ORM should be at the project layer (due to their nature of changing rapidly).

Turns out, still going with the NoSQL solution. Although it seems like everyone have convinced themselves that NoSQL is faster development processes than a simple table with constraints.

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In the projects I've worked on that require frequent table modification, I came to the opinion that the correct approach would be to store the data where the columns/values are stored in a table or set of tables based on types and linked together with a relationship to the original table as the parent. The big downside I could see is performance, but maybe I'm falsely assuming that this would still be faster than NoSQL? (I haven't actually used nosql however.) But, for my projects, the performance hit should/would not be a problem.

Since my experience is probably just limited, I'm curious if there is an easy to explain example where this is incorrect? (Or I guess maybe most people disagree with me and see my above opinion as always/most of the time incorrect)

This is correct if I understand you. Basically, when people add something new to a schema, they're generally tacitly also admitting it's optional. Optional fields should not exist on the same table as non-optional fields, because then you have to allow everything to be null or a specially designated value.

I will agree with your approach. With any large system or government database schema adding another table and then adding a relation to the necessary reports is 100x better than changing the parent table.

I've seen too often jobs being quoted for clients for simply adding a column to table blow out to 4-5 month development tasks. Turns out the table was being used by an old C/C++ program with oracle C bindings. That had to be updated, and that in turn caused another application to stop working.

Leaf node dependencies should be very stable. Otherwise you spend all your time rebuilding or at least rerunning integration tests. I work at a company that has achieved the opposite of that with not one but two libraries, and deployment is a miserable experience.

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