R/clear.R

In nicolewhite/RNeo4j: Neo4j Driver for R

#' Clear the Database
#' 
#' Delete all nodes, relationships, constraints, and indexes from Neo4j.
#' 
#' @param graph A graph object.
#' @param input A logical constant. If \code{FALSE}, do not require user input for confirmation.
#' 
#' @examples 
#' \dontrun{
#' graph = startGraph("http://localhost:7474/db/data/")
#' clear(graph)
#' }
#' 
#' @export
clear = function(graph, input = TRUE) UseMethod("clear")

#' @export
clear.graph = function(graph, input = TRUE) {
  stopifnot(is.logical(input))
  
  if(input == FALSE) {
    answer = "Y"
  } else{
    message("You are about to delete all nodes, relationships, indexes, and constraints from the graph database. Are you sure? Y/N")
    answer = scan(what = character(), nmax = 1, quiet = TRUE)
  }

  if(answer == "Y") {
    suppressMessages(dropConstraint(graph, all = TRUE))
    suppressMessages(dropIndex(graph, all = TRUE))
    query = "MATCH (n) OPTIONAL MATCH (n)-[r]-() DELETE n,r"
    suppressMessages(cypher(graph, query))
    
  } else if(answer == "N") {
    stop("Delete aborted.")
  }
  else {
    stop("You must answer Y or N.")
  }
}