Generates the summary of a server-side object

Generates the summary of a server-side object.

ds.summary(x = NULL, datasources = NULL)

Arguments

x

a character string specifying the name of a numeric or factor variable.

datasources

a list of DSConnection-class objects obtained after login. If the datasources argument is not specified the default set of connections will be used: see datashield.connections_default.

Value

ds.summary returns to the client-side the class and size of the server-side object. Also other information is returned depending on the class of the object. For example, potentially disclosive information such as the minimum and maximum values of numeric vectors are not returned. The summary is given for each study separately.

Details

This function provides some insight about an object. Unlike the similar native R summary function only a limited class of objects can be used as input to reduce the risk of disclosure. For example, the minimum and the maximum values of a numeric vector are not given to the client because they are potentially disclosive.

server functions called: isValidDS, dimDS and colnamesDS

Author

DataSHIELD Development Team

Examples

if (FALSE) { # \dontrun{

  ## Version 6, for version 5 see the Wiki 
  
  # Connecting to the Opal servers

  require('DSI')
  require('DSOpal')
  require('dsBaseClient')

  builder <- DSI::newDSLoginBuilder()
  builder$append(server = "study1", 
                 url = "http://192.168.56.100:8080/", 
                 user = "administrator", password = "datashield_test&", 
                 table = "CNSIM.CNSIM1", driver = "OpalDriver")
  builder$append(server = "study2", 
                 url = "http://192.168.56.100:8080/", 
                 user = "administrator", password = "datashield_test&", 
                 table = "CNSIM.CNSIM2", driver = "OpalDriver")
  builder$append(server = "study3",
                 url = "http://192.168.56.100:8080/", 
                 user = "administrator", password = "datashield_test&", 
                 table = "CNSIM.CNSIM3", driver = "OpalDriver")
  logindata <- builder$build()

  # Log onto the remote Opal training servers
  connections <- DSI::datashield.login(logins = logindata, assign = TRUE, symbol = "D") 
  
  #Calculate the summary of a numeric variable
  
  ds.summary(x = "D$LAB_TSC",
             datasources = connections)
 
  #Calculate the summary of a factor variable

  ds.summary(x = "D$PM_BMI_CATEGORICAL",
             datasources = connections)
                                
  # Clear the Datashield R sessions and logout  
  datashield.logout(connections) 

} # }