execute <- function()

in R/R/executeInSQL.R [222:325]

• 77 lines of code
• 14 McCabe index (conditional complexity)

execute <- function(connection, script, ...)
{
    queryResult <- NULL

    # Check if the connection is a connection string or an odbc connection object (S4 object)
    #
    if (class(connection) == "character")
    {
        if (nchar(connection) < 1)
        {
            stop(paste0("Invalid connection string: ", connection), call. = FALSE)
        }
    }
    else if (typeof(connection) != "S4")
    {
        stop("Invalid connection string has to be a character string or odbc handle", call. = FALSE)
    }

    tryCatch(
    {
        # If we have a connection string, connect, then disconnect on exit.
        # If we have an actual connection object, use it but don't disconnect on exit.
        #
        if (class(connection) == "character")
        {
            hodbc <- connectToServer(connection)
            on.exit(dbDisconnect(hodbc), add = TRUE)
        }
        else
        {
            hodbc <- connection
        }

        queryResult <- dbSendQuery(hodbc, script)

        # Bind parameterized queries
        #
        if(length(list(...)) != 0)
        {
            dbBind(queryResult, ...)
        }

        res <- dbFetch(queryResult)

        binVal <- res$returnVal
    },
    error = function(e)
    {
        stop(paste0("Error in SQL Execution: ", e, "\n"))
    },
    finally =
    {
        if (!is.null(queryResult))
        {
            dbClearResult(queryResult)
        }
    })

    binVal <- res$returnVal

    if (!is.null(binVal))
    {
        resVal <- unserialize(unlist(lapply(lapply(as.character(binVal),as.hexmode), as.raw)))
        len <- length(resVal)

        # Each piece of the returned value is a different part of the output
        # 1. The result of the function
        # 2. The output of the function (e.g. from print())
        # 3. The warnings of the function
        # 4. The errors of the function
        # We raise warnings and errors, print any output, and return the actual function results to the user
        #
        if (len > 1)
        {
            output <- resVal[[2]]
            for (o in output)
            {
                cat(paste0(o,"\n"))
            }
        }

        if (len > 2)
        {
            warnings <- resVal[[3]]
            for (w in warnings)
            {
                warning(w)
            }
        }

        if (len > 3)
        {
            errors <- resVal[[4]]
            for (e in errors)
            {
                stop(paste0("Error in script: ", e))
            }
        }

        res <- resVal
    }

    return(res)
}