VB.Net/Database ADO.net/SqlCommand Delete
Версия от 16:40, 26 мая 2010; (обсуждение)
Delete database record
Imports System
Imports System.Data
Imports System.Data.SqlClient
public class MainClass
Shared Sub Main()
Dim thisConnection As New SqlConnection("server=(local)\SQLEXPRESS;" & _
"integrated security=sspi;database=MyDatabase")
Dim sql As String = "SELECT * FROM Employee"
Dim deleteSql As String = _
"DELETE FROM Employee " & _
"WHERE ID = @ID"
Try
Dim da As New SqlDataAdapter
da.SelectCommand = New SqlCommand(sql, thisConnection)
Dim ds As New DataSet
da.Fill(ds, "Employee")
Dim dt As DataTable = ds.Tables("Employee")
Console.WriteLine("Before altering the dataset")
For Each row As DataRow In dt.Rows
Console.WriteLine("{0} | {1} | {2}", _
row("ID").ToString().PadRight(10), _
row("FirstName").ToString().PadRight(10), _
row("LastName"))
Next
Dim deleteCmd As New SqlCommand(deleteSql, thisConnection)
deleteCmd.Parameters.Add("@ID", _
SqlDbType.Int, 4, "ID")
Dim filter1 As String = _
"firstname = "Joe" and lastname = "Yin""
For Each row As DataRow In dt.Select(filter1)
row.Delete()
Next
da.DeleteCommand = deleteCmd
da.Update(ds, "employee")
Console.WriteLine("After altering the dataset")
For Each row As DataRow In dt.Rows
Console.WriteLine("{0} | {1} | {2}", _
row("ID").ToString().PadRight(10), _
row("FirstName").ToString().PadRight(10), _
row("LastName"))
Next
Catch ex As SqlException
Console.WriteLine("Error: " & ex.ToString())
Finally
thisConnection.Close()
Console.WriteLine("Connection Closed")
End Try
End Sub
End Class
Execute Delete command and check the result
Imports System
Imports System.Data
Imports System.Data.SqlClient
public class MainClass
Shared Sub Main()
Dim thisConnection As New SqlConnection("server=(local)\SQLEXPRESS;" & _
"integrated security=sspi;database=MyDatabase")
"Create Command object
Dim nonqueryCommand As SqlCommand = thisConnection.CreateCommand()
Try
" Open Connection
thisConnection.Open()
Console.WriteLine("Connection Opened")
"Create Command objects
Dim scalarCommand As New SqlCommand("SELECT COUNT(*) FROM Employee", thisConnection)
" Execute Scalar Query
Console.WriteLine("Before INSERT, Number of Employees = {0}", _
scalarCommand.ExecuteScalar())
" Set up and execute DELETE Command
nonqueryCommand.rumandText = _
"DELETE FROM Employee WHERE " & _
"Firstname="A" AND Lastname="A""
Console.WriteLine("Executing {0}", nonqueryCommand.rumandText)
Console.WriteLine("Number of rows affected : {0}", _
nonqueryCommand.ExecuteNonQuery())
" Execute Scalar Query
Console.WriteLine("After Delete, Number of Employee = {0}", _
scalarCommand.ExecuteScalar())
Catch ex As SqlException
" Display error
Console.WriteLine("Error: " & ex.ToString())
Finally
" Close Connection
thisConnection.Close()
Console.WriteLine("Connection Closed")
End Try
End Sub
End Class