R/normalise.r

In autodb: Automatic Database Normalisation for Data Frames

#' Create normalised database schemas from functional dependencies
#'
#' Creates a database schema from given functional dependencies, satisfying at
#' least third normal form, using Bernstein's synthesis.
#'
#' This is a wrapper function for applying \code{\link{synthesise}} and
#' \code{\link{autoref}}, in order. For creating relation schemas and foreign
#' key references separately, use these functions directly. See both functions
#' for examples.
#'
#' For details on the synthesis algorithm used, see \code{\link{synthesise}}.
#'
#' @param dependencies a \code{\link{functional_dependency}} object, as given by
#'   \code{\link{discover}}.
#' @param ensure_lossless a logical, TRUE by default. If TRUE, and the
#'   decomposition isn't lossless, an extra relation is added to make the
#'   decomposition lossless.
#' @param reduce_attributes a logical, TRUE by default. If TRUE,
#'   \code{dependencies} are checked for determinant attributes that are made
#'   redundant by the other dependencies. This is redundant if
#'   \code{dependencies} is output from \code{discover}, since there will be no
#'   such redundant attributes.
#' @inheritParams autodb
#'
#' @return A \code{\link{database_schema}} object, containing the synthesis
#'   relation schemas and the created foreign key references.
#' @export
normalise <- function(
  dependencies,
  single_ref = FALSE,
  ensure_lossless = TRUE,
  reduce_attributes = TRUE,
  remove_avoidable = FALSE,
  constants_name = "constants",
  progress = FALSE,
  progress_file = ""
) {
  autoref(
    synthesise(
      dependencies,
      ensure_lossless = ensure_lossless,
      reduce_attributes = reduce_attributes,
      remove_avoidable = remove_avoidable,
      constants_name = constants_name,
      progress = progress,
      progress_file = progress_file
    ),
    single_ref = single_ref
  )
}