Delete Command

Delete Command

 

Add a Button control to the Web Forms page and paste the following code.

Private Sub Delete_Click(ByVal sender As System.Object, ByVal e As_ System.EventArgs) Handles Delete.Click Try myConn = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;_ Data Source=C:\sandeep\books.mdb;") myConn.Open() myComm = New OleDbCommand("Delete from Table1 where isbn=192435211", myConn) Dim sa As Integer = myComm.ExecuteNonQuery() Response.Write("Records deleted" & " " & sa) Catch End Try End Sub

System.Data.SqlClient The System.Data.SqlClient namespace provides classes that are required to connect to SQL Server. Let's take a look at the classes provided by System.Data.SqlClient. SqlConnection Class The SqlConnection class represents a connection to SQL Server data source. SqlCommand Class The SqlCommand class represents a SQL statement or stored procedure for use in a database with SQL Server. SqlDataReader The SqlDataReader class creates a data reader to be used with SQL Server. SqlDataAdapter The SqlDataAdapter class represents a bridge between the dataset and the SQL Server database. It includes the Select, Insert, Delete and Update commands for loading and updating the data. Code Samples The following code samples will put the System.Data.SqlClient namespace and the classes within it to work. Select Command Open a new Web Forms page, add a Button to it and paste the following code. The following code will display data from Discounts table in Pubs sample database. Imports System.Data.SqlClient Dim myConnection As SqlConnection Dim myCommand As SqlCommand Private Sub Page_Load(ByVal sender As System.Object, ByVal e As_ System.EventArgs) Handles MyBase.Load End Sub Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As_ System.EventArgs) Handles Button1.Click myConnection = New SqlConnection("server=localhost;uid=sa;pwd=;database=pubs") 'establishing connection. you need to provide password for sql server Try myConnection.Open() 'opening the connection myCommand = New SqlCommand("Select * from discounts", myConnection) Dim dr As SqlDataReader = myCommand.ExecuteReader() While dr.Read() 'reading from the datareader Response.Write(dr(0).ToString()) Response.Write(dr(1).ToString()) Response.Write(dr(2).ToString()) Response.Write(dr(3).ToString()) Response.Write(dr(4).ToString()) 'displaying data from the table End While dr.Close() myConnection.Close() Catch End Try End Sub Insert Command Add a Button control to the Web Forms page and paste the following code. The following code will insert a record into the Jobs table in Pubs sample database. Private Sub Button2_Click(ByVal sender As System.Object, ByVal e_ As System.EventArgs) Handles Button2.Click Dim ra As Integer myConnection = New SqlConnection("server=localhost;uid=sa;pwd=;database=pubs") 'you need to provide password for sql server myConnection.Open() myCommand = New SqlCommand("Insert into Jobs values 12,'IT Manager',100,300 ", myConnection) ra= myCommand.ExecuteNonQuery() 'Since no value is returned we use ExecuteNonQuery Response.Write("Records Inserted" & ra) myConnection.Close() End Sub Delete Command Add a Button to the Web Forms page and paste the following code. The following code will delete a record from the Authors table in Pubs sample database. Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As_ System.EventArgs) Handles Button3.Click Dim ss As Integer myConnection = New SqlConnection("server=localhost;uid=sa;pwd=;database=pubs") myConnection.Open() myCommand = New SqlCommand("Delete from Authors where city='Oakland' ", myConnection) ss = myCommand.ExecuteNonQuery() Response.Write("Records affected" & ss) myConnection.Close() End Sub Update Command Add a Button to the Web Forms page and paste the following code. The following code will update a record in Authors table. Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As_ System.EventArgs) Handles Button4.Click Dim sss As Integer myConnection = New SqlConnection("server=localhost;uid=sa;pwd=;database=pubs") myConnection.Open() myCommand = New SqlCommand("Update Authors Set city='Oakland' where city='San Jose' ",_ myConnection) sss = myCommand.ExecuteNonQuery() Response.Write("Records affected" & sss) myConnection.Close() End Sub