更新查询不起作用 vb net

Question

当我尝试使用以下查询更新数据库时，我收到消息“更新成功”，但事实并非如此，我的数据仍然和以前一样。

Public Function alterar() As Boolean
    Dim cd As New npgSqlCommand
    Dim query As String = ""

    Try
       query &= "UPDATE [Caixa] SET Recibo = '" & iRecibo & "' ,  CentroCusto = '" & sCentroCusto & "' ,  Data = '" & sData & "' , Dia = '" & sDia & "' , _
       Mes ='" & sMes & "', Ano = '" & sAno & "' , CentroCustoResumo = '" & sCentroCustoResumo & "' , CodSubCentroCusto ='" & sCodSubCentroCusto & "', _
        DescSubCentroCusto ='" & sDescSubCentroCusto & "', Eventos ='" & sEventos & "', Historico = '" & sHistorico & "' , _
       Dinheiro = '" & sDinheiro & "', Cheque = '" & sCheque & "', Cartao = '" & sCartao & "', DepositoDireto = '" & sDepositoDireto & "', _
       Total ='" & sTotal &  "' WHERE Recibo = '" & iRecibo.ToString()

        If Conexao.NonQuery(cd) Then
            sStatus = "O Recibo " & iRecibo & " foi alterado com sucesso!"
            Return True
        End If
    Catch ex As Exception
        sStatus = ex.Message
    End Try
    Return True
End Function

Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
    Dim c As New Caixa()
    Try
        If TextBox1.Text <> "" Then
            c.Recibo = CInt(TextBox1.Text)

            If c.excluir() Then
                MessageBox.Show(c.Status)
                CaixaLoad()
            Else
                MessageBox.Show(c.Status)
            End If
        Else
            MessageBox.Show("Nenhum registro selecionado!")
        End If
    Catch ex As Exception
        'MessageBox.Show(ex.Message)
    End Try
End Sub

我的查询有什么问题？

Answer 1

修复代码

试试下面的代码，（1）我用cmd.ExecuteNonQuery()代替Conexao.NonQuery(cd)，（2）query字符串没有分配给cmd命令，（3）[]括号没有使用在 postgresql 中，如果需要，您必须使用双引号。 (4) 使用 npgsqlcommand 类时推荐使用Using

Public Function alterar() As Boolean

    Dim query As String = ""
    Try

       query = "UPDATE Caixa SET Recibo = '" & iRecibo & "' ,  CentroCusto = '" & sCentroCusto & "' ,  Data = '" & sData & "' , Dia = '" & sDia & "' , " &  _
       "Mes ='" & sMes & "', Ano = '" & sAno & "' , CentroCustoResumo = '" & sCentroCustoResumo & "' , CodSubCentroCusto ='" & sCodSubCentroCusto & "', " &  _
       "DescSubCentroCusto ='" & sDescSubCentroCusto & "', Eventos ='" & sEventos & "', Historico = '" & sHistorico & "' , " & _
       "Dinheiro = '" & sDinheiro & "', Cheque = '" & sCheque & "', Cartao = '" & sCartao & "', DepositoDireto = '" & sDepositoDireto & "', " & _
       "Total ='" & sTotal &  "' WHERE Recibo = '" & iRecibo.ToString & "'"

        Using cmd As New npgSqlCommand

            cmd.CommandText = query
            cmd.Connection = conn 

            cmd.ExecuteNonQuery()
            sStatus = "O Recibo " & iRecibo & " foi alterado com sucesso!"

        End Using

        Return True



    Catch ex As Exception
        sStatus = ex.Message
        Return False
    End Try

End Function

参数化查询

建议使用参数化查询以获得更好的安全性（更安全地防止 sql 注入）和更好的性能，您可以关注这些类似的问题以获取更多信息：

• Update command using Npgsql postgres and C#

参考文献

• Npgsql Documentation
• Quoting columns with spaces in PostgreSQL?