Connect to MySQL database with RMySQL - r

I am making the move from RSQLite to RMySQL and I am confused by the user and password fields. FWIW, I'm running Windows 7, R 2.12.2, MySQL 5.5 (all 64 bit), and RMySQL 0.7-5.
I installed RMySQL as prescribed in this previous SO question, and as far as I know it works (i.e., I can load the package with library(RMySQL)). But when I try to run the tutorial from the R data import guide, I get a "failed to connect to database..." error. This is the code from the tutorial from the guide:
library(RMySQL) # will load DBI as well
## open a connection to a MySQL database
con <- dbConnect(dbDriver("MySQL"), user = "root", password = "root", dbname = "pookas")
## list the tables in the database
dbListTables(con)
## load a data frame into the database, deleting any existing copy
data(USArrests)
dbWriteTable(con, "arrests", USArrests, overwrite = TRUE)
dbListTables(con)
## get the whole table
dbReadTable(con, "arrests")
## Select from the loaded table
dbGetQuery(con, paste("select row_names, Murder from arrests",
"where Rape > 30 order by Murder"))
dbRemoveTable(con, "arrests")
dbDisconnect(con)
On the second line I get the following error:
> con <- dbConnect(dbDriver("MySQL"), user = "richard", password = "root", dbname = "pookas")
Error in mysqlNewConnection(drv, ...) :
RS-DBI driver: (Failed to connect to database: Error: Access denied for user 'richard'#'localhost' (using password: NO)
)
I have tried with and without user and password and with admin as user. I have also tried using a dbname that I made before with the command line and with one that doesn't exist.
Any tips? Is there a good reference here? Thanks!

That is most likely a setup issue on the server side. Make sure that networked access is enabled.
Also, a local test with the command-line client is not equivalent as that typically uses sockets. The mysql server logs may be helpful.

First try to connect to MySQL server using MySQL Workbench or command line mysql using the same parameter. If it connects then R should also be able to connect.
Typically this issue comes when MySQL server doesn't allow connections from remote machines.

As people have told you, you can try to connect to the host with other application as mysql workbench. How odd! When I have tried in RStudio to connect to my db with your code without indicate the host in the command I haven't been able to connect.
I have needed to indicate the host ( host = 'localhost' ) in the command.

Related

R times out when accessing POSTGRESQL db

I'm using the POSTGRESQL package to access a database and R times out and crashes every time when connecting ("The previous R session was terminated due to an unexpected crash"). Terminal says 'abrt-cli status' timed out.
I've tried accessing the same db through SSH and it works. Our sysadmin thinks the credentials are correct, and says R seems to be working fine for him (although he's doing completely different work that has nothing to do with accessing postgresql databases). I've tried naming the server rather than using 'localhost', just in case, and that doesn't work either. But even if the credentials were wrong, I feel like I'd get an error rather than a crash.
I realize this might have to do with our local configuration, but I'm at the end of my rope. I'd be extremely grateful for any ideas people have.
# Install the package RPostgres
knitr::opts_chunk$set(echo = TRUE)
library(DBI)
library(RPostgreSQL)
library(tidycensus)
# The user needs to input their password
input_password <- rstudioapi::askForPassword("Database password")
db <- [CENSORED, I PROMISE IT'S CORRECT :)]
host_db <- 'localhost'
db_port <- '5432'
db_user <- 'leviem'
db_password <- input_password
drv <- dbDriver("PostgreSQL")
conn <- dbConnect(drv,
dbname = db,
host = host_db,
port = db_port,
user = db_user,
password = db_password)
# List all the tables available
dbListTables(conn)
# Close the connection
dbDisconnect (conn)

RStudio on Windows PostgreSQL SSL Connection with RPostgreSQL

I am having trouble creating an SSL connection using RPostgreSQL to an AWS hosted PostgreSQL database.
Here is what I've tried so far:
Created the PostgreSQL database on AWS.
Set the database parameter "rds.force_ssl" to 1.
Downloaded the AWS public key from https://s3.amazonaws.com/rds-downloads/rds-combined-ca-bundle.pem
Test the connection from a windows command prompt with psql (it works).
Executed the following in R:
library(RPostgreSQL)
cert <- paste0("C:/Users/johnr/Downloads/", "rds-combined-ca-bundle.pem")
dbname <- paste0("dbname=", "flargnog", " ", "sslrootcert=", cert, " ", "sslmode=verify-full")
host <- "xxxxxx.xxxxx.us-region-2.rds.amazonaws.com"
con <- dbConnect(dbDriver("PostgreSQL"), user="username", host=host, port=5432, dbname=dbname, password="abcd1234!")
I receive an error message after executing the last statement:
Error in postgresqlNewConnection(drv, ...) :
RS-DBI driver: (could not connect username#xxxxxx.xxxxx.us-region-2.rds.amazonaws.com on dbname "flargnog"
If I change the rds.force_ssl setting to 0 (and remove the ssl stuff from dbname) the connection works just fine.
I have looked at other posts on Stackoverflow related to this issue. This and this seem to indicate an SSL connection is not possible due to issues with RPostgreSQL. However, this post indicates that you can.
Any guidance would be appreciated!
You can try to ssh to the rds instance using e.g. putty and port-forward your local port 5432 to the remote port 5432. Once the ssh connection is open in R just connect to localhost:5432...
Here is how to port-forward using putty:
http://www.akadia.com/services/ssh_putty.html
Here is how this works via command-line:
https://gist.github.com/magnetikonline/3d239b82265398568f31
P.S.: Make sure your instance is in a security-group that accepts ssh connections - port 22

Acces denied MariaDB Amazon-rds instance RMySQL and OBDC (windows)

I'm trying to connect R with my MariaDB instance (10.0 - Amazon RDS). Connection works fine in HeidiSQL. Both in R and ODBC drivers installation (direct and indirect), next error is prompted:
Error in .local(drv, ...) :
Failed to connect to database: Error: Access denied for user 'user'#'localhost' (using password: YES)
My account is the admin account of this instance, I used the following code:
library(RMySQL)
mySqlCreds <- list(dbhostname = "dbname.rds.amazonaws.com" , dbname="dbnamefull" , username = "user",pass = "secret", port = 3306)
drv <- dbDriver("MySQL")
dbConnect(drv, host=mySqlCreds$dbhostname, dbname=mySqlCreds$dbname, user=mySqlCreds$username, password=mySqlCreds$pass, port = mySqlCreds$port)
Same problem while connecting an ODBC driver in Windows to this instance- finds database, but again no access. Even after modifying instance parameter groups in aws console, log_bin_trust_function_creators to 1, and rebooting the database.
If you know how to solve this issue, please let me know! Thank you in advance!

Connect with rpostgresql

I have build up a postgresql 9.2 database. My table looks like that:
CREATE DATABASE "EURUSD_M1"
WITH OWNER = fadmin
ENCODING = 'UTF8'
TABLESPACE = pg_default
LC_COLLATE = 'German_Germany.1252'
LC_CTYPE = 'German_Germany.1252'
CONNECTION LIMIT = -1;
However when trying to connect thorugh the rpostgresql driver I get:
> drv <- dbDriver("PostgreSQL") ## loads the PostgreSQL driver
> con <- dbConnect(drv, port='5432', dbname='EURUSD_M1',
+ user='fadmin') ## Open a connection
Error in postgresqlNewConnection(drv, ...) :
RS-DBI driver: (could not connect fadmin#local on dbname "EURUSD_M1"
)
btw to specify host = 'localhost' does not change anything! Also fadmin is a superuser in my db!
Here are further connection information:
Any ideas what I am doing wrong?
I appreciate your answers!
RPostgreSQL, just like the psql command-line tool, connect via tcp/ip network interface even when you have the server on the same machine.
For this to work, you must enable network access; see the various PostreSQL HOWTOs and guides. You probably have to edit / alter a file call pg_hba.conf or similar.

Importing files from PostgreSQL to R

I have a large data-set and I will preform some analysis in R software.
While I could not import the data properly to R.
I get this error:
Error in postgresqlNewConnection(drv, ...) : RS-DBI driver: (could not connect User#local on dbname "Intel"
I have used PostgreSQL to open data and somehow manage it. How can I import the existing data in the PostgreSQL to the R software?
drv <- dbDriver("PostgreSQL")
con <- dbConnect(drv, host='localhost', port='5432', dbname='Swiss',
user='postgres', password='123456')
Moreover, "RPostgreSQL" package in R should be installed.
Try the R package RPostgreSQL http://cran.r-project.org/web/packages/RPostgreSQL/ .
You can see how to use it in http://code.google.com/p/rpostgresql/ .
Example:
library(RPostgreSQL)
drv <- dbDriver("PostgreSQL") ## loads the PostgreSQL driver
con <- dbConnect(drv, dbname="R_Project") ## Open a connection
rs <- dbSendQuery(con, "select * from R_Users") ## Submits a statement
fetch(rs,n=-1) ## fetch all elements from the result set
dbGetQuery(con, "select * from R_packages") ## Submit and execute the query
dbDisconnect(con) ## Closes the connection
dbUnloadDriver(drv) # Frees all the resources on the driver
You have to configure two things on the PostgreSQL server before you are able to connect remotely. This is a instruction how to configure this under Linux:
1. Find and configure postgresql.conf to allow the TCP service to accept connections from any host, not only localhost
find / -name "postgresql.conf"
In my linux OS the file is locate in /etc/postgresql/9.6/main/, so I modify it there. Add the line "listen_addresses = '*'" as follows:
/etc/postgresql/9.6/main/postgresql.conf
#listen_addresses = 'localhost' # what IP address(es) to listen on;
# insert the following line
listen_addresses = '*'
2. Find and configure pg_hba.conf to allow to connect with a client from any host
sudo find / -name "pg_hba.conf"
In my linux OS the file is locate in /etc/postgresql/9.6/main/, so I modify it there. Add the line "host all all 0.0.0.0/0" as follows:
sudo nano /etc/postgresql/9.6/main/pg_hba.conf
# Put your actual configuration here
# ----------------------------------
#
# If you want to allow non-local connections, you need to add more
# "host" records. In that case you will also need to make PostgreSQL
# listen on a non-local interface via the listen_addresses
# configuration parameter, or via the -i or -h command line switches.
#
# insert the following line
host all all 0.0.0.0/0 trust
3. Stop and start the server
sudo service postgresql stop
sudo service postgresql start
4. Connect with you client, now it should work.
GOOD LUCK!

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