在vb.net中获取单值表单数据库 [英] fetching single value form database in vb.net

问题描述

我的桌子

id     姓名

1      abc

2      xyz

我输入 1 然后各自的值 abc显示在不同的文本框中???

my table
id       name
1       abc
2       xyz
it i enter 1 then respective value "abc" display in different text box???

Private Sub butsea_Click(sender As Object, e As EventArgs) Handles butsea.Click
 
        Dim dset As New DataSet
        Dim da As SqlDataAdapter
        Dim myCmd As New SqlCommand
 
        Try
       myConn.ConnectionString = "Data Source=THEONE\PARTH;Initial Catalog=testdatabase;Integrated Security=True;"
            myConn.Open()
 
            Dim avalue As String = (InputBox("Input Student Id", "Search Student")).ToString
            txt_id.Text = avalue
            da = New SqlDataAdapter("SELECT * FROM studentdetails where student_id= '" & txt_id.Text & "", myConn)
            If dset.Tables(0).Rows.Count > 0 Then
               'what should i write here
            Else
                MsgBox("No Record Found")
            End If
           
        Catch ex As Exception
            MsgBox(ex.Message)
        Finally
            myConn.Close()
        End Try
 
    End Sub

推荐答案

If dset.Tables(0).Rows.Count > 0 Then
              txt_name.Text = dset.Tables(0).Rows(0)("name").ToString()
            Else
                MsgBox("No Record Found")
            End If

0）不要将数据访问代码放在UI代码中;写一个数据访问层和一个业务逻辑层

1）使用参数化查询，而不是连接

2）不要使用 * 如果你只需要一个值（或几个）

3）不要使用DataSet来获得一个值

4）不要使用DataAdapter获取一个值



5）我建议使用ExecuteScalar

0) Don't put data access code in your UI code; write a Data Access Layer and a business logic layer
1) Use parameterized queries, not concatenation
2) Don't use * if you only want one value (or a few)
3) Don't use a DataSet to get one value
4) Don't use a DataAdapter to get one value

5) I recommend using ExecuteScalar

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