vb.net – 从数据库中删除时,SQL逻辑错误或缺少数据库没有此类表

Public con As SQLiteConnection = New SQLiteConnection("Data Source=trancebeats.s3db")

并在表单加载时打开连接

插入新值：

Public Sub InsertNewCatSub()
        prUpdate.Value = 0
        prUpdate.Maximum = 1
        lblUpdateResults.Text = prUpdate.Value & " of " & prUpdate.Maximum & " Checked"
        lblUpdateResults.ForeColor = Color.Red
        TotUpd = 0
        TotNew = 0
        Dim filename1 = Path.GetFileNameWithoutExtension(NewCat)
        Dim filename2 = filename1.Replace("[", "")
        Dim filename3 = filename2.Replace("]", "")
        Dim filename4 = Path.GetDirectoryName(NewCat)
        If con.State = ConnectionState.Closed Then
            con.Open()
        End If
        Dim Querytxt As String = "Select * from trancebeats Where Cat = '" & filename3 & "' Group By Cat"
        Dim Adp As SQLiteDataAdapter = New SQLiteDataAdapter
        Dim Cmd As SQLiteCommand = New SQLiteCommand
        Dim TableNewCat As New DataTable
        TableNewCat.Rows.Clear()
        Dim i As Integer

        With Cmd
            .CommandText = Querytxt
            .Connection = con
        End With

        With Adp
            .SelectCommand = Cmd
            .Fill(TableNewCat)
        End With
        If TableNewCat.Rows.Count > 0 Then
            For i = 0 To TableNewCat.Rows.Count - 1
                If filename3 = TableNewCat.Rows(i)("Cat") Then
                    MsgBox("Cat. Already Exists!!!")
                Else
                    GoTo write_new_cat
                End If
            Next
        Else
write_new_cat:
            Try
                Dim file As String = NewCat
                Dim filepath As String = file.Substring(0, file.LastIndexOf("\"))
                Dim lines As New List(Of String)
                lines.AddRange(System.IO.File.ReadAllLines(NewCat))

                For co As Integer = 0 To lines.Count - 1
                    If lines(co).Length > 0 Then
                        Try
                            Dim a1() As String = lines(co).Split("|")

                            Dim Cat As String = a1(0)
                            Dim Title As String = a1(1)
                            Dim Artist As String = a1(2)
                            Dim Album As String = a1(3)
                            Dim Year As String = a1(4)
                            Dim Genre As String = a1(5)
                            Dim Publisher As String = a1(6)
                            Dim Site As String = a1(7)
                            Dim MP3File As String = filepath & "\" & a1(8)
                            Dim Cover As String = filepath & "\[" & Cat & "].jpg"
                            Dim CmdwrtN As SQLiteCommand = New SQLiteCommand
                            With CmdwrtN
                                .CommandText = "Insert Into trancebeats Values('" _
                                & Cat & "', '" & Title & "', '" & Artist & "', '" & Album & "', " & Year & ", '" & Genre & "', '" & Publisher & "', '" & Site & "', '" & filepath.Replace("'", "''") & "', '" & Cover.Replace("'", "''") & "', '" & MP3File.Replace("'", "''") & "')"
                                .Connection = con
                                .ExecuteScalar()
                            End With
                        Catch ex As Exception
                            MsgBox(ex.Message & NewCat)
                        End Try
                    End If
                Next
                TotNew += 1
            Catch ex As Exception
                MessageBox.Show(ex.ToString, "Error Reading File " & NewCat)
            End Try
            btnClear.Enabled = True
        End If
        con.Close()
        prUpdate.Value += 1
        lblUpdateResults.Text = prUpdate.Value & " of " & prUpdate.Maximum & " Checked"
    End Sub

从数据库删除所有内容

Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
    If con.State = ConnectionState.Closed Then
        con.Open()
    End If

    Dim Querytxt As String = "Delete from trancebeats"
    Dim Cmd As SQLiteCommand = New SQLiteCommand
    Try
        With Cmd
            .CommandText = Querytxt
            .Connection = con
            .ExecuteScalar()
            MsgBox("Data Cleared")
            Dim pn As Panel
            pn = Me.Controls.Item("pnNew")
            Me.Controls.Remove(pn)
            flResults.Controls.Clear()
            btnClear.Enabled = False
        End With
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try

End Sub

当我清除数据库
我从文件中插入一个新行
然后当我尝试清除数据库时
它给了我一个错误：

SQL逻辑错误或缺少数据库没有这样的表：trancebeats

在我的情况下,事实证明我的连接字符串将数据库指定为相对路径：

'URI=file: mydatabase.sqlite'

一切正常,直到我在我的应用程序中使用’OpenFileDialog’.这会更改当前目录,并抛出连接字符串.快速修复,在连接字符串中使用数据库的绝对路径：

'URI=file: C:\Test\mydatabase.sqlite'