Main function
The first function called when Vertica runs an R user-defined extension (UDx). It must return a data frame and is defined by the name parameter of the factory function.
Example
FunctionName <- function(input_data_frame, parameters_data_frame) {
# Each column from Vertica is turned into a column in the input data frame.
# This is a brief example of multiplying two columns of the input data frame.
output_data_frame <- data.frame(input_data_frame[, 1] * input_data_frame[, 2])
# The function must return a data frame.
return(output_data_frame)
}
Arguments
input_data_frame |
The data read by the Vertica user-defined extension (UDx). This input must be a data frame. |
parameters_data_frame |
The parameters passed to the Vertica user-defined extension (UDx). This input must be a data frame. If you are passing parameters from your Vertica UDx, defined with USING PARAMETERS, then you must included this in your R UDx. If you are not passing parameters to your R UDx, then this can be omitted from your R UDx. |
Description
The main function takes as input one data frame as the first argument, and if your UDx accepts parameters, a parameter data frame as the second argument. The main function must return a data frame. The factory function converts the intype argument into a data frame for the main function. For example, intype=c("float","float") is converted by the factory function into a two-dimensional matrix.
The function can call other functions defined in your R UDx library file.