R packages installation error solved

Most of the common error we are getting below  in R at the time of installing in R packages like(rJava,ggplot2...)

Warning message:
package ‘rJava’ is not available (for R version 3.0.2)

In this post we ll see how to resolve this error.

First login as root user 

and type R and you ll get r prompt

>

then type 

 install.packages("rJava")

it ll ask package mirror location give any one it ll installed without any issue.

To confirm the package installation 

try below line

library(rJava)

It won't throw any message so its installed .

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Install R in Redhat 7.2

Installation of R in redhat is simple.

First download the below file

wget http://public-yum.oracle.com/public-yum-ol7.repo

open the downloaded file and change enabled property into 1

vi public-yum-ol7.repo

[ol7_latest]
enabled=1

[ol7_addons]
enabled=1

[ol7_optional_latest]
enabled = 1

then

 sudo yum install R.x86_64

Now R is installed.. 

typr R you ll get 

R>

error:

If you are getting below error 

Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle

GPG key retrieval failed: [Errno 14] curl#37 - "Couldn't open file /etc/pki/rpm-gpg/RPM-GPG-KEY-oracle"

Try the below command to download oracle gpg file

wget http://public-yum.oracle.com/RPM-GPG-KEY-oracle-ol7 -O /etc/pki/rpm-gpg/RPM-GPG-KEY-oracle

then

sudo yum install R.x86_64

issue has resolved..

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Connect R with MYSQL database

R is simple and has more features.
In this post we can see how write R code to connect Mysql DB which is installed in azure platform.

I am using R studio .

 RJDBC package to connect Mysql.
First install RJDBC  by using following command in R studio

Here we are insert records in table and fetch the result by R script

DB name is Department
Table name is Maths

install.packages("RJDBC")

mydb = dbConnect(MySQL(), user='root', password='root', host='jay_hadoop.cloudapp.net', dbname="Department")

To insert value in Maths table

query1=dbGetQuery(mydb, "INSERT INTO Maths (StudentName, City) VALUES ('Saswath','Bangalore');")

To fetch values from table Maths

table_values <-dbGetQuery(mydb, "select * from Maths")

print(table_values)

You will get 

Saswath   Bangalore

then finally close the connection by

dbDisconnect(mydb)

Results are stored in Dataframe table_values , Now you can write r dataframe code .  RJDBC is easy and simple to connect R with mysql.

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