Gordon Linoff
2020-11-28 20:37:28
No. In all databases that I know of, the primary key index is a B-tree index. Finding a particular element in such an index is an O(log n) operation, not O(1).
Note that for the sizes of databases, O(log n) is pretty close to O(1). After all, the log of one billion is only about 30 (base 2).