Probelm with parallelzing sql query in R

I am new to R and was doing a academic project and i was trying to extract some data from data base. It works normally (without parallelizing )when i parallelize it show some error. i want to get the result for query and check the value is above 100, if so then i must store the result in frame else skip to next id.

while (nflights < number_of_flights) {
query = paste("SELECT longitude AS lon, latitude AS lat,",
            "CONVERT(serial, UNSIGNED) AS serial,",
            nflights, "as flight",
            "FROM ***** m, ***** p",
            "WHERE m.id=p.id",
            "AND serial=******",
            "AND flight=", startID,
            "ORDER BY m.time")
positions <- select(query)// is function written for extracting data
startID <- startID+1

# not enough positions, try next
if (nrow(positions) < positions_per_flight) next

parallelizing query

for (i in seq(nflights, number_of_flights, by=increment)) {

  max_i = if (i+increment-1<number_of_flights) i+increment-1 else number_of_flights

 foreach(f=startID:startID + 10,.combine='rbind',.inorder=FALSE,
             .multicombine=TRUE,.errorhandling="stop") %dopar% {

              con <- dbConnect(MySQL(),user="****", password="********",dbname="******", host="**********")
              query = paste("SELECT longitude AS lon, latitude AS lat,",
                            "CONVERT(serial, UNSIGNED) AS serial,",
                            nflights, "as flight",
                            "FROM ****** m,******  p",
                            "WHERE m.id=p.id",
                            "AND serial=*****",
                            "AND flight=", startID,
                            "ORDER BY m.time")

              positions<-dbGetQuery(ch,query) 
              startID <- startID+1
            #  dbClearResult(positions)
              if (nrow(positions) > positions_per_flight){
                positions <- positions[idc,]
                positions <- cbind(positions, data.frame(i=1:positions_per_flight))
              }
            }

}

i am getting error "Error in { : task 1 failed - "could not find function "dbConnect""" also with dbQuery too"

i installed and import all the packages, it works when i do it serial manner!

any tips??

thanks in advance