正在更新远程访问服务器

Question

在创建我的程序时，我发现用包提供本地数据库会更可靠，而不是为每个实例连接到远程数据库。

以下是我关于如何做到这一点的想法，但我希望它能为它找到的每个不同的主机自动发生，而不是选择每个成员并按下按钮。这是我不知道如何实现的事情。

Imports System.Data.OleDb
Public Class Form1    
Dim con as oledbconnection = new oledbconnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source='.localDB.accdb'")
Dim rem as oledbconnection = new oledbconnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source='\serverremote.accdb'")
dim da as new oledbdataadaptor
dim dt as new datatable
dim dt2 as new datatable
Dim Str as string
Dim cmd as new oledbcommand(str, con)
Private Sub Form1_load
con.open()
da.SelectCommand = New OleDbCommand("select distinct Host from Logs")
da.fill(dt)
con.close
Combobox1.datasource = dt
Combobox1.displaymember = "Host"
End Sub
Private Sub button1_click
con.open()
Dim cmd As New OleDbCommand("select * from local where host=@host;", con)
cmd.parameters.addwithvalue("@host", combobox1.text.tostring)
da.fill(dt2)
con.close()
rem.open()
Dim cmd1 As New OleDbCommand("update remote set col1=@col1 where ID=@ID;", con)
cmd1.parameters.addwithvalue("@col1", dt2.rows(0).item(1).tostring)
cmd1.parameters.addwithvalue("@ID", dt2.rows(0).item(0).tostring)
rem.close()
End Sub
End Class

任何想法都将不胜感激。

*需要注意的是，我意识到JET提供了同步功能，但数据库必须是2007-10格式，所以ACE是唯一的选择。

Answer 1

首先，OleDbCommand不接受命名参数，因此您需要使用?引用它们，并按照它们出现的顺序传递参数。

Dim cmd As New OleDbCommand("select * from local where host = ?", con)
cmd.parameters.Add(combobox1.Text.ToString)

完成后，您需要用SQL语句的结果填充DataSet

    Dim DA As New OleDbDataAdapter(cmd)
    Dim DS As New DataSet
    DA.Fill(DS, "hosts")

更新

为了有一个与你相同的代码，我会做一些类似的

Imports System.Data.OleDb
Public Class Form1
Dim con as oledbconnection = new oledbconnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source='.localDB.accdb'")
Dim rem as oledbconnection = new oledbconnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source='\serverremote.accdb'")
dim dt as New DataTable
Dim Str as String
Dim cmd as New OleDbCommand(str, con)

Private Sub Form1_load
con.open()
da.SelectCommand = New OleDbCommand("select distinct Host from Logs")
da.fill(dt)
con.close

For Each DR as DataRow In DT.Rows
con.open()
Dim cmd As New OleDbCommand("select * from local where host= ? ", con)
cmd.Parameters.Add(DR.Item(0))
Dim DA As New SqlClient.SqlDataAdapter(cmd)
Dim DS As New DataSet
da.Fill(DS,"hosts")
con.close()
rem.open()
Dim cmd As New OleDbCommand("update remote set col1=? where ID=?", rem)
cmd.Parameters.Add(DS.Tables("hosts").Rows(0).Item(1).ToString)
cmd.Parameters.Add(DS.Tables("hosts").Rows(0).Item(0).ToString)
cmd.ExecuteNonQuery()
rem.close()
Next
End Sub
End Class