> POSTQUEL allows users to save and query historical data and versions [KATZ85, WOOD83]. By default, data in a relation is never deleted or updated. Conventional retrievals always access the current tuples in the relation. Historical data can be accessed by indicating the desired time when defining a tuple variable.
Or, to put it another way [1]:
"Since one can't change the past, this implies that the database accumulates facts, rather than updates places, and that while the past may be forgotten, it is immutable."
> POSTQUEL allows users to save and query historical data and versions [KATZ85, WOOD83]. By default, data in a relation is never deleted or updated. Conventional retrievals always access the current tuples in the relation. Historical data can be accessed by indicating the desired time when defining a tuple variable.
Or, to put it another way [1]:
"Since one can't change the past, this implies that the database accumulates facts, rather than updates places, and that while the past may be forgotten, it is immutable."
&:)
[1] https://www.infoq.com/articles/Datomic-Information-Model
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