spark_write_jdbc(members_df,
name = "Mbrs",
options = list(
url = paste0("jdbc:mysql://",mysql_host,":",mysql_port,"/",dbname),
user = mysql_user,
password = mysql_password),
mode = "append")
Results in the following exception:
Error: java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getDriver(DriverManager.java:315)
The .jar file is in a folder on the server where RStudio is running, config details below. We're able to access MySql via the RMySql package so MySql is working and accessible.
config$`spark.sparklyr.shell.driver-class-path` <- "/dev/shm/temp/mysql-connector-java-5.1.44-bin.jar"
Even if the question is different, I think the answer still applies also to this:
How to use a predicate while reading from JDBC connection?
Code to connect to JDBC MySQL through sparklyr (I made some slight changes to simplify the code a bit, written by Jake Russ)
library(sparklyr)
library(dplyr)
config <- spark_config()
#config$`sparklyr.shell.driver-class-path` <- "E:\\spark232_hadoop27\\jars\\mysql-connector-java-5.1.47-bin.jar"
#in my case, using RStudio and Sparkly this seemed to be optional
sc <- spark_connect(master = "local")
db_tbl <- spark_read_jdbc(sc,
name = "table_name",
options = list(url = "jdbc:mysql://localhost:3306/schema_name",
user = "root",
password = "password",
dbtable = "table_name"))
Related
I have a R Shiny Application which uses MySQL as a datasource. When the application loads and the user logs into the app with their username and password, a database connection interface opens up where the user inputs their MySQL credentials. In order to prevent the app from crashing when the user enters the wrong MySQL connection credential, I am trying to use the following error handling.
# run when Load Data button is clicked
datapms <- eventReactive(input$pull_data, {
req(input$db_user,input$db_user,input$db_password,input$db_name,input$db_host,input$db_port)
progress <- Progress$new(session, min=1, max=15)
on.exit(progress$close())
progress$set(message = 'Pulling data from database',
detail = 'This message will disappear once completed.')
# establish a database connection
tryCatch({
con <- RMySQL::dbConnect(
RMySQL::MySQL(),
user = input$db_user,
password = input$db_password,
dbname = input$db_name,
host = input$db_host
)
}, error = function(e) {
debug_msg(e$message)
})
# construct the SQL statement
sql <- "SELECT * FROM pmsanalytics;"
# Fetch data
pmsanalytics <- tryCatch({
pmsanalytics <- dbGetQuery(conn = con, sql)
}, error = function(e) {
debug_msg(e$message)
})
### display debugging message in R (if local)
### and in the console log (if running in shiny)
debug_msg <- function(...) {
is_local <- Sys.getenv('SHINY_PORT') == ""
in_shiny <- !is.null(shiny::getDefaultReactiveDomain())
txt <- toString(list(...))
if (is_local) message(txt)
if (in_shiny) shinyjs::runjs(sprintf("console.debug(\"%s\")", text))
}
Initially this code was working, and the app was not crashing. However, now, when for example one enters the wrong connection credentials, i am getting the following error message:
Warning: Error in as.character: cannot coerce type 'closure' to vector of type 'character'
138: sprintf
136: debug_msg [C:\PMSAnalytics/app.R#107]
135: value[[3L]] [C:\PMSAnalytics/app.R#211]
134: tryCatchOne
133: tryCatchList
132: tryCatch
131: eventReactiveValueFunc [C:\PMSAnalytics/app.R#202]
Basically, the app crashes because there is no data which it is expecting to get, in other words the reactive datapms() data source it is expecting to get is empty.
Kind assist in reviewing my code to prevent app crashing.
Regards,
Chris
My Shiny App was crushing when wrong connection credentials were passed to the connection string. I then put my connection string within a tryCatch as follows:
,,,
ConnectToDb <- function(){
con <- tryCatch({
dbConnect(MySQL(),
user = input$db_user,
password = input$db_password,
dbname = input$db_name,
host = input$db_host,
port = input$db_port)
print("Connection made")
####
sql <- "SELECT * FROM PMSAnalytics;"
data <- dbGetQuery(con, sql)
# # Disconnect from the DB
dbDisconnect(con)
# # Convert to data.frame
data <- data.frame(data)
data$timestamp <- as_datetime(now())
data
####
}, error = function(e) {
message('Please confirm your login details')
print(e)
},
warning = function(w){
message('A warning has occured')
print(w)
return(NA)
}
)
}
,,,
Now the application does not crush, but however no error messages or warning are passed when wrong credentials are used and neither do I get a connection success. I have checked this site for similar questions, but I seem not to get any. Kindly assist with polishing the code.
Regards,
Chris
I work with showNotification, which directly shows a notification in the shiny UI, you could also use it for the connection success.
Also, Options for this are,
duration = 60 (in this case for 60 seconds)
closeButton = FALSE
For example:
error = function(e) {
showNotification(paste0(e), type = 'error')
}
warning = function(w){
showNotification(paste0(w), type = 'warning')
return(NA)
}
I'm using the R package monitoR and getting an error message that I can't figure out.
I'm trying to upload a correlation template list ("bithTemps") to a MySQL database ("noh") using the dbUploadTemplate command.
dbUploadTemplate(templates = bithTemps,
uid = "root",
pwd = "****",
db.name = "noh",
analyst = 1,
locationID = "2",
date.recorded = "2017/09/07",
recording.equip = "Unknown",
species.code = "BITH",
type = "COR")
This returns:
Error: $ operator is invalid for atomic vectors
I have confirmed the ODBC connection is working, that the template list is functional (i.e., it works when called to other arguments in the package), and that the SQL database has the required entries for analyst, location, and species code.
It seems that this error was actually triggered by a non-functional ODBC connection. This part of the dbUploadTemplate function
species <- RODBC::sqlQuery(dbCon, paste("SELECT `pkSpeciesID`, `fldSpeciesCode` FROM `tblSpecies` WHERE `fldSpeciesCode` = '",
paste(species.code, sep = "", collapse = "' OR `fldSpeciesCode` = '"),
"'", sep = ""))
queries a table in the SQL database and returns an object called 'species'. If the query fails (e.g., because RODBC can't connect) than 'species' is empty, and the following operation
speciesID <- NULL
for (i in 1:length(species.code)) {
speciesID[i] <- species$pkSpeciesID[species$fldSpeciesCode ==
species.code[i]]
}
triggers the error. Fixing the ODBC connection resolves the error.
I was wondering if someone could help with this annoying issue.
I'm trying to create/make multiple connections to different database.
I have a data.frame with 3 connection credentials named conf - It works if I manually enter the connections variable like so:
conn <- dbConnect(MySQL(), user=conf$user, password=conf$passws, host=conf$host, dbname=conf$db)
which ends up creating a single connection.
However, what I want is to be able to refer to the connection as:
conf$conn <- dbConnect(MySQL(), user=conf$user, password=conf$passws, host=conf$host, dbname=conf$db)
here is the error message I'm getting.
Error in rep(value, length.out = nrows) :
attempt to replicate an object of type 'S4'
I think the problem is how I'm adding conf$conn
I used a combination of the pool and config package to solve a similar problem to set up a number of simultaneous PostgreSQL connections. Note that this solution needs a config.yml file with the connection properties for db1 and db2.
library(pool)
library(RPostgreSQL)
connect <- function(cfg) {
config <- config::get(config = cfg)
dbPool(
drv = dbDriver("PostgreSQL", max.con = 100),
dbname = config$dbname,
host = config$host,
port = config$port,
user = config$user,
password = config$password
)
}
conn <- lapply(c("db1", "db2"), connect)
How can I connect to a MySQL database from using Lua programming language?
If a good/popular library exists, what is it?
Minimal woking example for LuaSQL - simple interface from Lua to a DBMS.
package.cpath = package.cpath .. ";/usr/lib/i386-linux-gnu/lua/5.1/?.so"
luasql = require "luasql.mysql"
env = assert (luasql.mysql())
con = assert (env:connect("dbname","user","password"))
cur = assert (con:execute("SHOW TABLES"))
row = cur:fetch ({}, "a")
while row do
print(string.format("Name: %s", row.Tables_in_dbname))
row = cur:fetch (row, "a")
end
Line 1 used if module luasql.mysql not found. Also environment variable LUA_CPATH may be used.
In case your mysql database is remote, you can add host as another optional parameter to connect. Port can follow host as well:
con = assert (env:connect("dbname","user","password","host",port))
From LuaSQL -- Database connectivity for the Lua programming language:
require "luasql.mysql"
env = assert (luasql.mysql())
con = assert (env:connect"my_db")
for id, name, address in rows (con, "select * from contacts") do
print (string.format ("%s: %s", name, address))
end