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  2. Set operations (SQL) - Wikipedia

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

    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 (,) times in the result set. Notably, the Oracle platform provides a MINUS operator which is functionally equivalent to the SQL standard EXCEPT DISTINCT operator. [3]

  3. Oracle machine - Wikipedia

    en.wikipedia.org/wiki/Oracle_machine

    An oracle machine can be conceived as a Turing machine connected to an oracle. The oracle, in this context, is an entity capable of solving some problem, which for example may be a decision problem or a function problem. The problem does not have to be computable; the oracle is not assumed to be a Turing machine or computer program.

  4. Relational algebra - Wikipedia

    en.wikipedia.org/wiki/Relational_algebra

    The relational algebra uses set union, set difference, and Cartesian product from set theory, and adds additional constraints to these operators to create new ones.. For set union and set difference, the two relations involved must be union-compatible—that is, the two relations must have the same set of attributes.

  5. Oracle complexity (optimization) - Wikipedia

    en.wikipedia.org/wiki/Oracle_complexity...

    ation, oracle complexity is a standard theoretical framework to study the computational requirements for solving classes of optimization problems. It is suitable for analyzing iterative algorithms which proceed by computing local information about the objective function at various points (such as the function's value, gradient , Hessian etc.).

  6. Disjoint-set data structure - Wikipedia

    en.wikipedia.org/wiki/Disjoint-set_data_structure

    MakeSet creates 8 singletons. After some operations of Union, some sets are grouped together. The operation Union(x, y) replaces the set containing x and the set containing y with their union. Union first uses Find to determine the roots of the trees containing x and y. If the roots are the same, there is nothing more to do.

  7. Java virtual machine - Wikipedia

    en.wikipedia.org/wiki/Java_virtual_machine

    A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally describes what is required in a JVM implementation.

  8. Operator (computer programming) - Wikipedia

    en.wikipedia.org/wiki/Operator_(computer...

    The scope resolution and element access operators (as in Foo::Bar and a.b, respectively) operate on identifier names; not values. In C, for instance, the array indexing operator can be used for both read access as well as assignment. In the following example, the increment operator reads the element value of an array and then assigns the ...

  9. Union type - Wikipedia

    en.wikipedia.org/wiki/Union_type

    The memory layout of unions in Rust is undefined by default, [8] but a union with the #[repr(C)] attribute will be laid out in memory exactly like the equivalent union in C. [9] Reading the fields of a union can only be done within an unsafe function or block, as the compiler cannot guarantee that the data in the union will be valid for the ...