I made registration on SAP ID Service to check how their sandbox works.
How it's possible to connect to the sandbox data tables by using R?
The examples I found:
library ("RODBC")
# 1
ch <- odbcConnect("data source name", uid = "test_hana" , pwd = "test12")
sqlQuery(ch, "SELECT * FROM '_SYS_BIC'.'BILLING_DATA'")
# 2
ch <- odbcConnect("HANA_TK", uid="xxxx", pwd="xxxx")
odbcQuery(ch, "SELECT table_name from SYS.CS_TABLES_ where schema_name = 'SFLIGHT'")
tables <- sqlGetResults(ch)
odbcClose(ch)
Both not work. And, it's unclear how to have access to at least one SAP table in the sandbox.
Any ideas are welcome!
You need to setup ODBC connection into HANA in system settings, here is how or here, and then you must install and load RODBC package in R:
> install.packages("RODBC")
> library("RODBC")
Then connect to HANA through the connection string:
> channel <- odbcConnect(“data source name”,uid=”test_hana”,pwd=”test12″);
and pull data like this:
> sqlQuery(channel, ‘SELECT * FROM “_SYS_BIC”.”BILLING_DATA” ‘)
Related
I have my ODBC query to connect to Teradata and just wonder if I can read in the SQL file as oppose to have SQL code in? I am trying to find R function for Python's pd.read_sql_query(f, con) where f is my SQL file with code.
So for my connection, it would change from:
con <- function(){
query <- paste0("
SELECT * FROM table1
")
print(queryData(query))
}
con<- data.frame(con())
to
con <- function(){
query <- "SQL_code.sql"
print(queryData(query))
}
con<- data.frame(con())
read your sql from a file:
sql_query <- read.delim('/path/SQL_code.sql', header = FALSE) %>% as.character()
then define the connection and use it:
library(DBI)
db <- dbConnect(...)
dbGetQuery(db, sql_query)
If I understand your question correctly, you could try something like this?
library(DBI)
library(readr)
df <- dbGetQuery(con, statement = read_file('SQL_code.sql'))
# con is your connection
If it does not solve your problem, there may be some solutions here: How to read the contents of an .sql file into an R script to run a query?
I am sure this question is very basic, but this is the first time I am using R connected to a server, so a few things still confuse me.
I used ODBC Data Sources on Windows to create a DNS, and used
con <- dbConnect(odbc::odbc(), "TEST_SERVER")
this worked, and now under the connection tab I can see the server, and if I double click I can see the databases and tables that exist in the server. How would I go about reading something inside one of those databases?
For Example, if the database name is db1, and the table name is t1, what is the code needed to read that table into local memory? I would prefer using dbplyr as I am familiar with the syntax. I am just unsure how to refer to a particular database and table after making the connection to the server.
I haven't used dbplyr before, but you can query the database using dbGetQuery.
test <- dbGetQuery(
con,
"SELECT *
FROM db1.t1
"
)
You can also pass the database into the connection string.
con <- dbConnect(
drv = odbc(),
dsn = "TEST_SERVER",
database = "db1"
)
And then your query would just be "SELECT * FROM t1".
EDIT: To query the table using dbplyr:
tbl1 <- tbl(con, "t1")
qry <- tbl1 %>% head() %>% collect()
I like to use RODBC-
con <- RODBC::odbcConnect(dsn = 'your_dsn',
uid = 'userid',
pwd = 'password')
table_output <- RODBC::sqlQuery(con, 'SELECT * FROM Table')
Using sparklyr I access a table from Oracle via JDBC in the following manner:
tbl_sample_stuff <- spark_read_jdbc(
sc = sc,
name = "tbl_spark_some_table",
options = list(
url = "jdbc:oracle:thin:#//my.host.with.data:0000/my.host.service.details",
driver = "oracle.jdbc.OracleDriver",
user = "MY_USERNAME",
password = "SOME_PASSWORD",
# dbtable = "(SELECT * FROM TABLE WHERE FIELD > 10) ALIAS"),
dbtable = "some_table"
),
memory = FALSE
)
The sample_stuff table is accessible. For instance running glimpse(tbl_sample_stuff) produces the required results.
Questions
Let's say I want to derive a simple count per group using the code below:
dta_tbl_sample_stuff_category <- tbl_sample_stuff %>%
count(category_variable) %>%
collect()
As a consequence my Spark 1.6.3 delivers the following job:
What is actually going on there, why there is a one collect job running first for a long period of time (~ 7 mins)? My view would be that the optimal approach would initially run some SQL like SELECT COUNT(category_variable) FROM table GROUP BY category_variable on that data and then collected the results. It feels to me that this job is downloading the data first and then aggregating, is that correct?
What's the optimal way of using JDBC connection via sparklyr. In particular, I would like to know:
What's wise in terms of creating temporary tables? Should I always create temporary tables for data I may want to analyse frequently?
Other details
I'm adding Oracle driver via
configDef$sparklyr.jars.default <- ora_jar_drv
Rest is typical connection to Spark cluster managed on Yarn returned as sc object to R session.
I have a connection to our database:
con <- dbConnect(odbc::odbc(), "myHive")
I know this is successful because when I run it, in the top right of RStudio I can see all of our databases and tables.
My question is, how can I select a specific database table combination? The documentation shows a user sleecting a single table, "flights" but I need to do the equivilent of somedatabase.sometable.
Tried:
mytable <- tbl(con, "somedb.sometable")
Error in new_result(connection#ptr, statement) :
nanodbc/nanodbc.cpp:1344: 42S02: [Hortonworks][SQLEngine] (31740) Table or view not found: HIVE..dp_enterprise.uds_order
Then tried:
mytable <- tbl(con, "somedb::sometable")
Error in new_result(connection#ptr, statement) :
nanodbc/nanodbc.cpp:1344: 42S02: [Hortonworks][SQLEngine] (31740) Table or view not found: HIVE..somedb::sometable
I tried removing the quotes "" too.
Within the connections pane of RStudio I can see somedb.sometable. It's there! How can I save it to variable mytable?
You select the database when creating the connection and the table when creating the tbl (with the from argument).
There is no standard interface to dbConnect, so the exact way to pass the database name depends on the DBDriver you use. Indeed DBI::dbConnect is simply a generic dispatching to the driver-specific dbConnect.
In your case, the driver is odbc so you can check out the documentation for odbc::dbConnect and you'll see the relevant argument is database.
This will work:
con <- dbConnect(odbc::odbc(), "myHive", database = "somedb")
df <- tbl(con, from = "sometable")
With most other drivers (e.g. RMariaDB, RMySQL, RPostgres, RSQLite), the argument is called dbname, so you'd do this:
con <- dbConnect(RMariaDB::MariaDB(), dbname = "somedb")
df <- tbl(con, from = "sometable")
I think I found it, use in_schema
mytable <- tbl(con, in_schema("somedb", "sometable"))
This returns a list not a tbl though so I'm not sure.
I am trying to add a new column to a table extracted from a MS Access database (*.accdb) and save it back again to MS Access using sqlSave(), but R-Studio shows FATAL ERROR and restarts.
install.packages("RODBC")
library("RODBC")
conn <- odbcConnect("TEST01", believeNRows=FALSE)
Departments <- sqlQuery(conn, "select * from Departments")
Departments$New <- c(2,2,2,2,2,2)
sqlSave(conn, dat=Departments, 'Departments', append=FALSE, rownames=FALSE)
The program seems to encounter a problem and crushes after a few seconds.
Does anyone know how to solve this problem?