Getting Records from a DataBase Using the DataReader Class in FSharp

Introduction:

The DataReader class is used in connected architectures in .NET. It is used for getting records from a Back-end (DataBase) to a Front-end interface control. Now we will create a F# application which will show records from a DataBase in a ListBox. At first we will create a DataBase and insert some records into the DataBase table.

Creating DataBase: We create a DataBase for binding. Here in my example, the DataBase name is student_record, table name is student and Columns are Roll_No and Name. I am using SQL server. I have written code for creating this database. Look at the below SQL statements.

create database student_record

use student_record

create table student
(   Roll_No int primary key,
    Name varchar(20) )

insert into student values(1,'Alok Pandey')

After creating DataBase and table, we start to develop F# application that will show record from DataBase using DataReader class. We follow the following steps for this.

Step 1: We open Visual Studio and create a F# application. 



The application page will look like the below figure.

Step 2: We go to Solution Explorer and Right Click on References. 
 

Step 3: Click on Add References. Then a pop-up window with caption Add Reference will open as below figure.

 

Step 4:Click at .NET on Add Reference window and select System.Windows.Forms, System.Drawing and System.Data with holding down Ctrl key and Click on Ok.



Step 5: Then write the below F# code in the Program.fs file.
 
//Adding NameSpace
 open System
 open System.Windows.Forms
 open System.Data.SqlClient 
 open System.Drawing
 //Connection String
 let constring = @"Data Source=Server_Name;Initial Catalog=student_record;Integrated Security=True"
 //Creating Window Form
 let frm = new Form()
 //Creating ListBox
 let list = new ListBox()
 //Adding Control(ListBox)
 frm.Controls.Add(list)
 //Creating SqlConnection
 let con = new SqlConnection(constring)
 //Open connection
 con.Open()
 //Creating SqlCommand
 let com = new SqlCommand()
 //Command Text
 com.CommandText <- "select name from student"
 //Making Connection
 com.Connection <- con
 //ExecuteReaader
 let dr = com.ExecuteReader()
 //Fetching Record into ListBox from DataBase
 if dr.Read() then
     for i = 0 to (dr.FieldCount - 1) do
     list.Items.Add(dr.Item(i))|>ignore
 //Closing DataReader
     dr.Close()
 //Closing Connection
     con.Close()
 Application.Run(frm)


The code window looks like the below figure.

Step 6: Run the application by pressing the Ctrl+F5 keys.