Problem using Quantmod and MySQL

On Mon, Mar 30, 2015 at 9:59 AM, Joshua Ulrich <josh.m.ulrich at gmail.com>
wrote:

On Mon, Mar 30, 2015 at 11:49 AM, Mark Knecht <markknecht at gmail.com>

wrote:

On Mon, Mar 30, 2015 at 9:25 AM, Joshua Ulrich <josh.m.ulrich at gmail.com>

wrote:

On Sun, Mar 29, 2015 at 5:37 PM, Joshua Ulrich <

josh.m.ulrich at gmail.com> wrote:

On Sun, Mar 29, 2015 at 1:50 PM, Ueli Hofstetter
<uelihofstetter at gmail.com> wrote:

I have some problems loading symbols from an mysql db using

getSymbols.

Instead of repeating the issue, here is a link to the description on
stackoverflow

http://stackoverflow.com/questions/29333330/quantmod-error-loading-symbols-from-mysql-db

Any help is greatly appreciated

The "character" method for dbConnect was removed in the 0.10 release
of RMySQL. I'm not sure whether or not this was intentional. It was
not mentioned in the release notes.

It was removed intentionally.  I do not have a MySQL database
available for testing, so I would really appreciate some help from
those who use this functionality.  Can someone please try this
suggested edit:
https://github.com/rstats-db/RMySQL/issues/62#issuecomment-87692704

And provide feedback at:

https://github.com/joshuaulrich/quantmod/issues/45

Thanks!
Josh


--
Joshua Ulrich  |  about.me/joshuaulrich
FOSS Trading  |  www.fosstrading.com

questions should go.

I'm happy to try it out but a little confused as to all the locations
I need to edit. Help me clear this up and I'll try it out immediately.

The failure is coming when I'm trying to get the data using the

following code:

if (DownloadNewData){

+   if (!UseMySQL){
+     for (i in 1:length(TestSym)){
+       print(paste("From ",SymbolSrc," -- ",TestSym[i]))
+       getSymbolsCont(TestSym[i], from = DataStart, to = DataEnd,
adjust = MyAdjust, src=SymbolSrc)
+     }
+   } else {
+     for (i in 1:length(TestSym)){
+       print(paste("From MySQL -- ",TestSym[i]))
+ #      getSymbols(TestSym[i], src="MySQL")
+       getSymbols(TestSym[i], src="MySQL", user="mark",
password="MyTempPassword", dbname=dbName)
+       assign(TestSym[i],

get(TestSym[i])[paste0(DataStart,"/",DataEnd)])

+     }
+     dbDisconnect(dbc)
+   }
+ }
[1] "From MySQL --  SPY"
 Show Traceback

 Rerun with Debug

Error in (function (classes, fdef, mtable)  :
  unable to find an inherited method for function ?dbConnect? for
signature ?"character"?


Am I correct that the suggestion is to edit two lines?

First, I use

library(RMySQL)

Is the first edit to change this to

requireNamespace("RMySQL", quietly = TRUE)

or do I add this to my code somewhere and keep the library command?

No, you shouldn't need to change anything in your code.

Later in my code I have:

if (UseMySQL){
  if (MyAdjust) { dbName = paste0(dbName, "Adjust")}
  dbc = dbConnect(MySQL(), dbname=dbName)
#  setDefaults(getSymbols.MySQL, user="mark",
password="MyTempPassword", dbname=dbName)
}

This would be where the second edit goes?

dbConnect("MySQL", ...) to dbConnect(RMySQL::MySQL, ...)

No. Again, you shouldn't need to change your code.  The change
required is on L614 of getSymbols.R.

Thanks,
Mark

--
Joshua Ulrich  |  about.me/joshuaulrich
FOSS Trading  |  www.fosstrading.com

In that case I'll leave it to someone else to test. I don't want to
mess with non-production libraries. My skill set in this code isn't
good.

Good luck,
Mark