R help - Feb 2010 - Help on R functions

Dear R Experts,
I have written a following function :-

myfunction<- function(servername,dbname,dbtablename){
library(RODBC)
channel <- odbcDriverConnect("driver=SQL Server;server=servername")
initdata<- sqlQuery(channel,paste("select * from  dbname .. 
dbtablename"))
return(dim(initdata))
}
I have written this function which has input  parameters like servername
,dbname and dbtable to connect to Ms SQL server 2005 and get data from the
table.
Now when I run this function using the following command

myfunction("01wh155073","test_DB","test_vikrant")


The variable initdata should contain all the data. But it does not contain
any data and dim(initdata)) is NULL.

I dont know how to pass the strings as parameters  in the function. Do I
have done this correctly?

If I run the same commands directly from the command line I get the expected
data.

library(RODBC)
channel <- odbcDriverConnect("driver=SQL Server;server=01wh155073")
initdata<- sqlQuery(channel,paste("select * from  test_DB .. 
test_vikrant"))
dim(initdata)

Then the initdata contains the data in the table "test_vikrant". My
question
is there a way to write above in a function which contains the above
parameters.
Please Help me...
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On 09/02/2010 7:10 AM, vikrant wrote:
> Dear R Experts,
> I have written a following function :-
> 
> myfunction<- function(servername,dbname,dbtablename){
> library(RODBC)
> channel <- odbcDriverConnect("driver=SQL
Server;server=servername")
> initdata<- sqlQuery(channel,paste("select * from  dbname .. 
dbtablename"))
> return(dim(initdata))
> }
> I have written this function which has input  parameters like servername
> ,dbname and dbtable to connect to Ms SQL server 2005 and get data from the
> table.
> Now when I run this function using the following command
> 
>
myfunction("01wh155073","test_DB","test_vikrant")
> 
> 
> The variable initdata should contain all the data. But it does not contain
> any data and dim(initdata)) is NULL.
> 
> I dont know how to pass the strings as parameters  in the function. Do I
> have done this correctly?
No.  "driver=SQL Server;server=servername" is a literal string.  If
you
want to replace servername with the contents of the servername argument, use

paste("driver=SQL Server;server=", servername, sep="")

and similarly for your query.

Duncan Murdoch
> 
> If I run the same commands directly from the command line I get the
expected
> data.
> 
> library(RODBC)
> channel <- odbcDriverConnect("driver=SQL
Server;server=01wh155073")
> initdata<- sqlQuery(channel,paste("select * from  test_DB .. 
> test_vikrant"))
> dim(initdata)
> 
> Then the initdata contains the data in the table "test_vikrant".
My question
> is there a way to write above in a function which contains the above
> parameters.
> Please Help me...