[okennedy]

From a practical standpoint for most database systems, sort of? One might say that there's a functional dependency from the 'time' to the 'precipitation' attribute, and providing that information to the optimizer might affect its decisions... but at the level of data storage and query evaluation runtimes, there's not a huge difference.

From a data modeling and query optimization perspective, however, there's some value in distinguishing attributes uniquely related to identity (e.g., keys, or group-by attributes) and attributes that we're only interested in computing statistics over. This makes it easier to automatically create e.g., data cubes or similar indexes, and many useful statistics can be modeled using a nice mathematical structure like a ring or semiring [1], who's properties (commutativity, associativity, distributivity) are very helpful when optimizing queries.

Classical Datalog, in particular, is entirely based on the former type of attribute; value (dependent) attributes always need to be hacked in, in some way.

[1] https://dl.acm.org/doi/10.1145/1265530.1265535