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MongoDB salesdroids rely heavily on you having a low familiarity with other database tech to spin themselves as the only game in town. "Being led astray" isn't

MongoDB salesdroids rely heavily on you having a low familiarity with other database tech to spin themselves as the only game in town. "Being led astray" isn't a passive, ambient occurence, and it makes sense to push back against it.

afiori 2y ago
On the other hand I know of multiple databases where all tables had attribute_1, attribute_2,..., attribute_5 columns Just in Case™ But more seriously the one feature I like in MongoDB is the pipeline API, where you can express a complex query with multiple filters/aggregations/transformations/joins as a list of simple steps. There are some use cases where it is very ergonomic (even if I suspect that mongo can easily lose indexes along the steps so pretty performance might not be super intuitive)
- regularfry 2y ago
  It's honestly difficult to see how this is relevant. There's a difference between just not knowing any better and being misled for money.
- afiori 2y ago
  I forgot about what I hate about mongo, so I will rant here about it: its data model is close enough but different enough from json to be both annoying and dangerous. The empty string is a valid json key but not a mongo document key. Mongo uses $operator keys to serialize its datatypes to json but does not sanitise the result: which means that {"foo":100000000000000000} and {"foo":{"$longInteger":"100000000000000000"}} will have a collision with the json export format. (Even if you choose the fully explicit Canonical format as there is no $document operator to wrap ambiguous documents) So if your plan is to dump json to mongo you should plan for that (also sometimes $operators are evaluated sometimes they are not, it depends on each method and the documentation does not tell you ) The official client (both csv and json) is unable to export a collection if a field is both a value field both an atomic value and an object, so a collection with two documents: {a:1} and {a:{b:1}} will cause problems of you try to export it. My colleagues have other issues with the json DSL and how most operators exist in 2-3 different forms with different syntax or how the syntax {$operator:{arg1:..., arg2:...}} is unintuitive but I actually sort of like it.

afiori 2y ago

On the other hand I know of multiple databases where all tables had attribute_1, attribute_2,..., attribute_5 columns Just in Case™ But more seriously the one feature I like in MongoDB is the pipeline API, where you can express a complex query with multiple filters/aggregations/transformations/joins as a list of simple steps. There are some use cases where it is very ergonomic (even if I suspect that mongo can easily lose indexes along the steps so pretty performance might not be super intuitive)

regularfry 2y ago
It's honestly difficult to see how this is relevant. There's a difference between just not knowing any better and being misled for money.
afiori 2y ago
I forgot about what I hate about mongo, so I will rant here about it: its data model is close enough but different enough from json to be both annoying and dangerous. The empty string is a valid json key but not a mongo document key. Mongo uses $operator keys to serialize its datatypes to json but does not sanitise the result: which means that {"foo":100000000000000000} and {"foo":{"$longInteger":"100000000000000000"}} will have a collision with the json export format. (Even if you choose the fully explicit Canonical format as there is no $document operator to wrap ambiguous documents) So if your plan is to dump json to mongo you should plan for that (also sometimes $operators are evaluated sometimes they are not, it depends on each method and the documentation does not tell you ) The official client (both csv and json) is unable to export a collection if a field is both a value field both an atomic value and an object, so a collection with two documents: {a:1} and {a:{b:1}} will cause problems of you try to export it. My colleagues have other issues with the json DSL and how most operators exist in 2-3 different forms with different syntax or how the syntax {$operator:{arg1:..., arg2:...}} is unintuitive but I actually sort of like it.