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  2. Rename (relational algebra) - Wikipedia

    en.wikipedia.org/wiki/Rename_(relational_algebra)

    In relational algebra, a rename is a unary operation written as / where: . R is a relation; a and b are attribute names; b is an attribute of R; The result is identical to R except that the b attribute in all tuples is renamed to a. [1]

  3. dplyr - Wikipedia

    en.wikipedia.org/wiki/Dplyr

    rename(), which enables a user to alter the column names for variables, often to improve ease of use and intuitive understanding of a dataset; slice_max() , which returns a data subset that contains the rows with the highest number of values for some particular variable;

  4. List of price index formulas - Wikipedia

    en.wikipedia.org/wiki/List_of_price_index_formulas

    The Marshall-Edgeworth index, credited to Marshall (1887) and Edgeworth (1925), [11] is a weighted relative of current period to base period sets of prices. This index uses the arithmetic average of the current and based period quantities for weighting. It is considered a pseudo-superlative formula and is symmetric. [12]

  5. Pivot table - Wikipedia

    en.wikipedia.org/wiki/Pivot_table

    Column labels are used to apply a filter to one or more columns that have to be shown in the pivot table. For instance if the "Salesperson" field is dragged to this area, then the table constructed will have values from the column "Sales Person", i.e., one will have a number of columns equal to the number of "Salesperson". There will also be ...

  6. Aggregate function - Wikipedia

    en.wikipedia.org/wiki/Aggregate_function

    Common aggregate functions include: Average (i.e., arithmetic mean) Count; Maximum; Median; Minimum; Mode; Range; Sum; Others include: Nanmean (mean ignoring NaN values, also known as "nil" or "null") Stddev; Formally, an aggregate function takes as input a set, a multiset (bag), or a list from some input domain I and outputs an element of an ...

  7. Aggregate (data warehouse) - Wikipedia

    en.wikipedia.org/wiki/Aggregate_(data_warehouse)

    An aggregate is a type of summary used in dimensional models of data warehouses to shorten the time it takes to provide answers to typical queries on large sets of data. The reason why aggregates can make such a dramatic increase in the performance of a data warehouse is the reduction of the number of rows to be accessed when responding to a query.

  8. Rename - Wikipedia

    en.wikipedia.org/wiki/Rename

    Rename may refer to: Rename (computing), rename of a file on a computer; RENAME (command), command to rename a file in various operating systems; Rename (relational algebra), unary operation in relational algebra; Company renaming, rename of a product; Name change, rename of a person; Geographical renaming, rename of a geographical location

  9. Database index - Wikipedia

    en.wikipedia.org/wiki/Database_index

    The data rows may be spread throughout the table regardless of the value of the indexed column or expression. The non-clustered index tree contains the index keys in sorted order, with the leaf level of the index containing the pointer to the record (page and the row number in the data page in page-organized engines; row offset in file ...