remove dupe

- Remove redundant declaration of transaction methods (#110, @@bborgesr).

R/DBConnection.R

@@ -311,50 +311,3 @@ setGeneric("dbRemoveTable",
   def = function(conn, name, ...) standardGeneric("dbRemoveTable"),
   valueClass = "logical"
 )
-
-#' Begin/commit/rollback SQL transactions
-#'
-#' Not all database engines implement transaction management, in which case
-#' these methods should not be implemented for the specific
-#' \code{\linkS4class{DBIConnection}} subclass.
-#'
-#' @section Side Effects:
-#' The current transaction on the connections \code{con} is committed or rolled
-#' back.
-#'
-#' @inheritParams dbDisconnect
-#' @return a logical indicating whether the operation succeeded or not.
-#' @examples
-#' \dontrun{
-#' ora <- dbDriver("Oracle")
-#' con <- dbConnect(ora)
-#' rs <- dbSendQuery(con,
-#'       "delete * from PURGE as p where p.wavelength<0.03")
-#' if(dbGetInfo(rs, what = "rowsAffected") > 250){
-#'   warning("dubious deletion -- rolling back transaction")
-#'   dbRollback(con)
-#' }
-#' }
-#' @name transactions
-NULL
-
-#' @export
-#' @rdname transactions
-setGeneric("dbBegin",
-  def = function(conn, ...) standardGeneric("dbBegin"),
-  valueClass = "logical"
-)
-
-#' @export
-#' @rdname transactions
-setGeneric("dbCommit",
-  def = function(conn, ...) standardGeneric("dbCommit"),
-  valueClass = "logical"
-)
-
-#' @export
-#' @rdname transactions
-setGeneric("dbRollback",
-  def = function(conn, ...) standardGeneric("dbRollback"),
-  valueClass = "logical"
-)