Getting warning message while using plot function

Question

I have my database table from which i retrieve a column and plot it using plot function.

Here is column of table

 Profit
 1   21200                    
 2   28000
 3   29600
 4   30200
 5   33000
 6   26800
 7   32600
 8   30000
 9   28000
10  34000

Here 60 rows are present but i am showing only 10 rows. when i try to plot the graph i am getting a straight line parallel to x axis but here profit is changing, so i don't think that it should parallel to x-axis.Since table is present in database in aws i am retrieving the profit column from table first then plotting using plot function.Here is plot function

 choices = dbGetQuery(pool,"select Profit from input11;")

plot(Choices, type = "l", lwd = 3, main = "Profit",col = "green", xlab = 
"Number of Overbooking", ylab = "Profit")

i am also getting warning messages here:

 Warning messages:
1: In plot.window(xlim, ylim, log, ...) :
  graphical parameter "type" is obsolete
2: In axis(side = side, at = at, labels = labels, ...) :
 graphical parameter "type" is obsolete
3: In title(xlab = xlab, ylab = ylab, ...) :
  graphical parameter "type" is obsolete

But when i remove type = "l", warning message disappears. But I want the plot in straight line format only.

Answer 1

Based on this R Help thread, the Profit column is class of factor, let's test:

Below works fine, when numeric:

plot(1:10, type = "l")

When we have factors, plots but with warnings:

plot(factor(1:10), type = "l")

Warning messages:
1: In plot.window(xlim, ylim, log = log, ...) :
  graphical parameter "type" is obsolete
2: In axis(if (horiz) 2 else 1, at = at.l, labels = names.arg, lty = axis.lty,  :
  graphical parameter "type" is obsolete
3: In title(main = main, sub = sub, xlab = xlab, ylab = ylab, ...) :
  graphical parameter "type" is obsolete
4: In axis(if (horiz) 1 else 2, cex.axis = cex.axis, ...) :
  graphical parameter "type" is obsolete