主题：怎样改代码定义到外部数据库

'编号生成'
Public _BizCodeBuilder As BizCodeBuilder

'不重复编号上传用,这里的用法比较简单,没有做复杂的编号规则处理'
Public Class BizCodeBuilder
    Private _bizcode As DataTable '直接把编号表取出到内存'
    Private _codelock As New Object
   
    Public Sub New(sjy As String)
        Dim cmd1 As New SQLCommand
        cmd1.C    '  外部数据库

        cmd1.commandText = "Selec t  * From {网络编号} "
        Dim sql = cmd1.commandText

' Dim sql = "Selec t * From {网络编号} "     ' 内部数据库

        _bizcode = Functions.Execute("Cmd_GetDataTable", sjy, sql, True)
    End Sub
   
    Public Function GetNextCode(s_name As String,Optional s_prefix As String = Nothing) As String
        SyncLock _codelock '使用锁处理并发
        Dim dr As DataRow = _bizcode.Find(CExp("BizName='{0}'", s_name))
        If dr Is Nothing Then
            '建议先在编号表中维护好需要产生编号的表,不用默认生成的编号规则'
            dr = _bizcode.AddNew()
            dr("BizName") = s_name
            dr("MaxValue") = 1
            If String.IsNullOrEmpty(s_prefix) Then s_prefix = Date.now.ToString("mmss") & "BH"
            dr("Prefix") = s_prefix
            dr("Mark") = "yyyyMMdd"
            dr("MarkValue") = Date.Today.ToString("yyyyMMdd")
            dr("Length") = 4
        Else
            '这里的处理规则是按时间进行重新编号,至于是按年,月还是日,在掩码中体现'
            If dr("MarkValue") <> Date.Today.ToString(dr("Mark")) Then
                dr("MaxValue") = 1
                dr("MarkValue") = Date.Today.ToString(dr("Mark"))
            Else
                dr("MaxValue") = dr("MaxValue") + 1
            End If
        End If
        dr.Save()
        Return dr("Prefix") & dr("MarkValue") & "-" & Format(dr("MaxValue"),"0000") '顺序号只取4位'
        End SyncLock
    End Function
End Class

请问怎样修改代码定义到外部数据库