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  2. Set operations (SQL) - Wikipedia

    en.wikipedia.org/wiki/Set_operations_(SQL)

    For purposes of row elimination and duplicate removal, the EXCEPT operator does not distinguish between NULLs. The EXCEPT ALL operator does not remove duplicates, but if a row appears X times in the first query and Y times in the second, it will appear max ( X − Y , 0 ) {\displaystyle \max(X-Y,0)} times in the result set.

  3. Skip list - Wikipedia

    en.wikipedia.org/wiki/Skip_list

    A schematic picture of the skip list data structure. Each box with an arrow represents a pointer and a row is a linked list giving a sparse subsequence; the numbered boxes (in yellow) at the bottom represent the ordered data sequence. Searching proceeds downwards from the sparsest subsequence at the top until consecutive elements bracketing the ...

  4. List of pythonid species and subspecies - Wikipedia

    en.wikipedia.org/wiki/List_of_pythonid_species...

    This is a list of all extant genera, species, and subspecies of the snakes of the family Pythonidae, otherwise referred to as pythonids or true pythons.It follows the taxonomy currently provided by ITIS, [1] which is based on the continuing work of Roy McDiarmid [2] and has been updated with additional recently described species.

  5. Null (SQL) - Wikipedia

    en.wikipedia.org/wiki/Null_(SQL)

    Although Don Chamberlin recognized nulls (alongside duplicate rows) as one of the most controversial features of SQL, he defended the design of Nulls in SQL invoking the pragmatic arguments that it was the least expensive form of system support for missing information, saving the programmer from many duplicative application-level checks (see ...

  6. List of set identities and relations - Wikipedia

    en.wikipedia.org/wiki/List_of_set_identities_and...

    Throughout this article, capital letters (such as ,,,,, and ) will denote sets.On the left hand side of an identity, typically, will be the leftmost set, will be the middle set, and

  7. Plex Inc. - Wikipedia

    en.wikipedia.org/wiki/Plex_Inc.

    Plex Inc. is an American software company that runs its namesake over-the-top ad-supported streaming television service, and allows discussion and discovery of content on major subscription streaming services.

  8. Binary search - Wikipedia

    en.wikipedia.org/wiki/Binary_search

    Binary search Visualization of the binary search algorithm where 7 is the target value Class Search algorithm Data structure Array Worst-case performance O (log n) Best-case performance O (1) Average performance O (log n) Worst-case space complexity O (1) Optimal Yes In computer science, binary search, also known as half-interval search, logarithmic search, or binary chop, is a search ...

  9. Lock (computer science) - Wikipedia

    en.wikipedia.org/wiki/Lock_(computer_science)

    The more fine-grained the available locks, the less likely one process/thread will request a lock held by the other. (For example, locking a row rather than the entire table, or locking a cell rather than the entire row); deadlock: the situation when each of at least two tasks is waiting for a lock that the other task holds. Unless something is ...