Introduction
In
this article we are trying to discuss about Using C# Code behind in U-SQL
script. As we look that every U-SQL script has a C# code behind.
Now
the question is why we are going to use this C# code behind as we can create
function, stored procedure and other thing successfully in U-SQL. The answer is
quite simple. If we want to use the power of C# and the entire library related
to it, we can use the C# code behind.
For an example, we need to create a complex scalar
value function and using C# it is quite easy by using it’s math library inbuilt
functionality.
Case Study
To understand the C# code behind, we are not taking
any complex example. Here we have a CSV file, that have “StudentID”, “StidentName”
,“Marks1”, “Marks2” and “Marks3”.
We
are going to retrieve information from CSV file and try to put the information
to another output CSV file.
We
are doing little transformation work by adding “Marks1”, “Marks2” and “Marks3”
and give it a “Total Marks”.
We
are going to use C# code behind by creating a function name “GetTotalMarks”. It
takes three input marks and returns the total of three input marks.
C# Code
Behind
using Microsoft.Analytics.Interfaces;
using Microsoft.Analytics.Types.Sql;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
namespace TestApplication
{
public static class StudentRecor
{
public static Double GetTotalMarks(int marks_1, int marks_2, int marks_3)
{
return marks_1 + marks_2 + marks_3;
}
}
}
U-SQL
Script
@searchlog =
EXTRACT StudentID int,
StudentName string,
Marks1 int,
Marks2 int,
Marks3 int
FROM "C:/Users/Joydeep/AppData/Local/USQLDataRoot/Input-1/StudentRecords.csv"
USING Extractors.Csv();
@filtering =
SELECT StudentID,
StudentName,
Marks1,
Marks2,
Marks3,
TestApplication.StudentRecor.GetTotalMarks(Marks1, Marks2, Marks3) AS TotalMarks
FROM @searchlog;
OUTPUT @filtering
TO "C:/Users/Joydeep/AppData/Local/USQLDataRoot/output/Output-1/StudentResult.csv"
USING Outputters.Csv();
Please
look at the calling of Function in U-SQL code.
It
is :
<Name Space
Name> . <Class Name>.<Function Name>
Job Graph:
Output
File
