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0 pointseinhverfr13y ago0 comments

IME SQL schemas do more harm than good

Completely disagree here. The basic tradeoff is between flexible input and flexible output. Without a rigid schema, ad hoc reporting is impossible because you don't have an ability to articulate reporting criteria. I.e. no declarative schema means no declarative reporting query.

I suppose that's ok as long as you never need to report on anything..... Might work....

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3 comments · 1 top-level

lmm13y ago· 2 in thread

I'm not saying don't have a rigid schema, just don't enforce it at the storage layer. If you're doing an ad-hoc report then you wouldn't have indexes in place for it in the SQL case, so I don't see how it's any worse or harder in mongodb.

einhverfrOP13y ago

>If you're doing an ad-hoc report then you wouldn't have indexes in place for it in the SQL case, so I don't see how it's any worse or harder in mongodb.

Only true in a case where you ahve to index everything you might want to search on, like with InnoDB. In PostgreSQL all you really need are your foreign key indexes and a couple (if that) of criteria indexes and you are good. That's more of an InnoDB limitation than a relational limitation. Basically InnoDB tables are primary key indexes and they can only be traversed in key order, not physical order, so sequential scans are painful....

lmm13y ago

If that level of indexing is sufficient I don't see why you can't just do the same thing in mongodb.

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