Retrieve rows from a database table in VB.NET

This article describes how to use ado.net to connect to a database and retrieve the rows from the database table.
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This article describes how to use ado.net to connect to a database and retrieve the row from the database table.To do that we use DataAdapter to retrieve the data from the database and place the data into DataSet. To fill the data into the DataSet use Fill method.

Creating connection object

To create a connection we pass the connection string as a parameter in connection object.
 

Dim str As String = "Data Source=.;uid=sa;pwd=123;database=master"

Dim con As New SqlConnection(str)

The above string defines the connection string which is used to connect the database with the application.

Now we create a database table and insert some values in this table. Table looks like this.

create table logn

(

username varchar(50),

password varchar(40)

)

go

insert into logn values('monu','mohan')

go

insert into logn values('Rohatash','rohit')

go

insert into logn values('Manoj','singh')

go

select * from logn;

The table looks like this.

d2.gif
 

Table1.gif

DataRow

DataRow represents a row of data in a data table.

Dim dr As DataRow

   For Each dr In ds.Tables(0).Rows

     Dim i As Integer

       For i = 1 To ds.Tables(0).Columns.Count

          Console.Write("{0,12}", dr(i - 1))

Next i

Console.WriteLine("")

For example

Imports System.Data.SqlClient

Module Module1

    Sub Main()

        Dim str As String = "Data Source=.;uid=sa;pwd=123;database=master"

        Dim con As New SqlConnection(str)

        Dim str1 As String = "SELECT * FROM logn"

        Dim cmd As New SqlCommand(str1, con)

        Dim da As New SqlDataAdapter(cmd)

        Dim ds As New DataSet()

        da.Fill(ds, "logn")

        Console.WriteLine("")

        Dim dr As DataRow

        For Each dr In ds.Tables(0).Rows

            Dim i As Integer

            For i = 1 To ds.Tables(0).Columns.Count

                Console.Write("{0,12}", dr(i - 1))

            Next i

            Console.WriteLine("")

        Next

    End Sub

End Module

OUTPUT


d1.gif

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