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I disagree with his conclusion which equates the database to functional programming. Relational algebra is a third paradigm on the same level as, and different

I disagree with his conclusion which equates the database to functional programming. Relational algebra is a third paradigm on the same level as, and different from, OOP and FP. I remember seeing an article pointing out that the database is the "mutable global variable in the middle of your functional program". Also both functional programming and object oriented programming make much more use of hierarchical organization and implementation hiding than do relational databases.

lenticular 8y ago
Relational algebra is essentially the same thing as logic programming, which is a separate paradigm. However, typeclasses get you a lot closer to the way normalized databases structure data than OOP does. Not that typeclasses are specifically FP, but they are currently only found in FP languages.
snidane 8y ago
This is exactly where typical pure lambda-calculus based programming falls short. Lambda calculus afaik doesn't have the concept of IO, so it has to be bolted on in the programming languages as an afterthought. I believe more powerful formalism has to be used. For example pi calculus or petri nets. In both you can represent the 'global variable database' as a process sitting somewhere and you communicate with it using channels or as a message passing in general. Lambda calculus is too constraining, because everything is a deterministic function and it can't model exactly this scenario. Another use case hard to model in lambda calculus is time. Eg. run some function after N seconds. Or plain 'sleep' function. When you now look at programming languages in terms of, let's say, Petri nets, you see clearly how OOP (Alan Kay's message passing) is the part where you send messages between processes and FP is contents of a particular process. Other than that, there are two types of OOP I noticed. 1. Alan Kay message passing. Originated from people trying to implement simulations 2. OOP as modules (Java, C++), aka 'Dog implements Animal' OOP. In this paradigm people try to come up with ontologies, ie. hierarchical models of data dependencies. Instead of using actual modules, people use classes for some reason. Then you can see module-like features implemented on classes, eg. private and public modifiers of methods. 'Dog implements Animal' should be modeled as 'Module Dog depends on module Animal'

lenticular 8y ago

Relational algebra is essentially the same thing as logic programming, which is a separate paradigm. However, typeclasses get you a lot closer to the way normalized databases structure data than OOP does. Not that typeclasses are specifically FP, but they are currently only found in FP languages.

snidane 8y ago

This is exactly where typical pure lambda-calculus based programming falls short. Lambda calculus afaik doesn't have the concept of IO, so it has to be bolted on in the programming languages as an afterthought. I believe more powerful formalism has to be used. For example pi calculus or petri nets. In both you can represent the 'global variable database' as a process sitting somewhere and you communicate with it using channels or as a message passing in general. Lambda calculus is too constraining, because everything is a deterministic function and it can't model exactly this scenario. Another use case hard to model in lambda calculus is time. Eg. run some function after N seconds. Or plain 'sleep' function. When you now look at programming languages in terms of, let's say, Petri nets, you see clearly how OOP (Alan Kay's message passing) is the part where you send messages between processes and FP is contents of a particular process. Other than that, there are two types of OOP I noticed. 1. Alan Kay message passing. Originated from people trying to implement simulations 2. OOP as modules (Java, C++), aka 'Dog implements Animal' OOP. In this paradigm people try to come up with ontologies, ie. hierarchical models of data dependencies. Instead of using actual modules, people use classes for some reason. Then you can see module-like features implemented on classes, eg. private and public modifiers of methods. 'Dog implements Animal' should be modeled as 'Module Dog depends on module Animal'