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  2. Aggregate function - Wikipedia

    en.wikipedia.org/wiki/Aggregate_function

    The input and output domains may be the same, such as for SUM, or may be different, such as for COUNT. Aggregate functions occur commonly in numerous programming languages, in spreadsheets, and in relational algebra. The listagg function, as defined in the SQL:2016 standard [2] aggregates data from multiple rows into a single concatenated string.

  3. Associative array - Wikipedia

    en.wikipedia.org/wiki/Associative_array

    This technique is simple and fast, with each dictionary operation taking constant time. However, the space requirement for this structure is the size of the entire keyspace, making it impractical unless the keyspace is small. [5] The two major approaches for implementing dictionaries are a hash table or a search tree. [3] [4] [5] [6]

  4. Sparse dictionary learning - Wikipedia

    en.wikipedia.org/wiki/Sparse_dictionary_learning

    Sparse dictionary learning (also known as sparse coding or SDL) is a representation learning method which aims to find a sparse representation of the input data in the form of a linear combination of basic elements as well as those basic elements themselves. These elements are called atoms, and they compose a dictionary.

  5. Data dictionary - Wikipedia

    en.wikipedia.org/wiki/Data_dictionary

    The terms data dictionary and data repository indicate a more general software utility than a catalogue. A catalogue is closely coupled with the DBMS software. It provides the information stored in it to the user and the DBA, but it is mainly accessed by the various software modules of the DBMS itself, such as DDL and DML compilers, the query optimiser, the transaction processor, report ...

  6. Checksum - Wikipedia

    en.wikipedia.org/wiki/Checksum

    Sum complement [ edit ] A variant of the previous algorithm is to add all the "words" as unsigned binary numbers, discarding any overflow bits, and append the two's complement of the total as the checksum.

  7. Algebraic data type - Wikipedia

    en.wikipedia.org/wiki/Algebraic_data_type

    The set of all possible values of a sum type is the set-theoretic sum, i.e., the disjoint union, of the sets of all possible values of its variants. Enumerated types are a special case of sum types in which the constructors take no arguments, as exactly one value is defined for each constructor.

  8. Lexicographic order - Wikipedia

    en.wikipedia.org/wiki/Lexicographic_order

    In mathematics, the lexicographic or lexicographical order (also known as lexical order, or dictionary order) is a generalization of the alphabetical order of the dictionaries to sequences of ordered symbols or, more generally, of elements of a totally ordered set. There are several variants and generalizations of the lexicographical ordering.

  9. Maximum subarray problem - Wikipedia

    en.wikipedia.org/wiki/Maximum_subarray_problem

    Maximum subarray problems arise in many fields, such as genomic sequence analysis and computer vision.. Genomic sequence analysis employs maximum subarray algorithms to identify important biological segments of protein sequences that have unusual properties, by assigning scores to points within the sequence that are positive when a motif to be recognized is present, and negative when it is not ...