R Extension

define function <function name>[<language name>] return <return type> {

   <operation of the function>

• function name: The name of the function.
• language name: The language of the script. In this scenario, it should be R.
• return type: The return type of the function (int, long, float, double, string, bool or object).
• operation of the function: The logic of the function.

define function concatFunction[R] return string {

   return(paste(data, collapse=""));

};

The above function takes n (variable) number of strings, concatenates them and returns the output. Input parameters are automatically input as an array.

A stream can be defined as follows.

define stream TempStream(deviceID long, roomNo int, temp double);

The eval script defined above can be used in this stream as follows.

from TempStream

select concatFunction(roomNo,deviceID) as id, temp  

insert into DeviceTempStream;