我是VB.NET和SQL中的新成员。我想更新我的数据库中的记录。我在我的数据库中做了一个假人。更新vb.net中的SQL语句
实施例中的值是:ID = 1,姓名=蛋白酶,年龄= 21
以我接口在VB.NET制成,我更新的值例如:名称= txtName.Text和年龄= txtAge.Text其中ID = 1。这是我的主要形式。在我的主窗体中,我有“查看”按钮,通知单击该按钮,将弹出新窗体,并查看用户更新的值。该程序没有任何错误,只是当我想再次更新SQL中的值时,它会记录BUT,当我再次单击“查看”按钮时,它会显示以前由用户输入的内容(运行界面时的第一次更新)。应该是什么解决方案?
这是我的代码:
的MainForm:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
SQLConnection.ConnectionString = ServerString
Try
If SQLConnection.State = ConnectionState.Closed Then
SQLConnection.Open()
MessageBox.Show("Successful connection")
Else
'SQLConnection.Close()
MessageBox.Show("Connection is closed")
End If
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub
Public Sub SaveNames(ByRef SQLStatement As String)
Dim cmd As MySqlCommand = New MySqlCommand
With cmd
.CommandText = SQLStatement
.CommandType = CommandType.Text
.Connection = SQLConnection
.ExecuteNonQuery()
End With
MsgBox("Successfully Added!")
End Sub
Private Sub cmdSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSave.Click
Dim date_now As String
date_now = Format(dtpDate.Value, "yyyy-MM-dd")
Dim SQLStatement As String = "UPDATE people SET name='" & txtName.Text & "', date ='" & date_now & "' WHERE 1"
SaveNames(SQLStatement)
End Sub
表2:(其中更新后的数据会被视为)
Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
SQLConnection.ConnectionString = ServerString
Try
If SQLConnection.State = ConnectionState.Closed Then
SQLConnection.Open()
'====retrieve/update values in database=============
Dim SQLStatement As String = "SELECT name, date FROM people"
ViewInfos(SQLStatement)
Else
'SQLConnection.Close()
MessageBox.Show("Connection is closed")
End If
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub
Public Sub ViewInfos(ByRef SQLStatement As String)
Dim cmd As MySqlCommand = New MySqlCommand
With cmd
.CommandText = SQLStatement
.CommandType = CommandType.Text
.Connection = SQLConnection
.ExecuteNonQuery()
End With
'--read the records in database in phpmyadmin gui---
Dim myReader As MySqlDataReader = cmd.ExecuteReader
If myReader.Read Then
lblName.Text = myReader.GetString(0)
lblDate.Text = myReader.GetString(1)
End If
myReader.Close()
MsgBox("Records Successfully Retrieved")
End Sub
任何帮助,将不胜感激。谢谢!
只是一个旁注:总是紧密联系立即(最好使用语句)。连接池实际上不会关闭它,但将其标记为_usable_。 – 2012-07-27 16:42:14
我认为它应该是Dim SQLStatement As String =“UPDATE people SET name ='”&txtName.Text&“',date ='”&date_now&''WHERE ID = 1“ – Mithrandir 2012-07-27 16:44:33
Noooo,不要连接字符串做sql语句! – King 2012-07-27 16:54:13