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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;
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]
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.
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Near the bottom of the left column, click New Folder. 2. Enter a new folder name. 3. Click the Save icon. Create a subfolder. 1. Mouse over the folder you want to add ...
Attributes are commonly represented as columns, tuples as rows, and relations as tables. A table is specified as a list of column definitions, each of which specifies a unique column name and the type of the values that are permitted for that column. An attribute value is the entry in a specific column and row.
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