用vb開數據庫代碼一問

Question

Private Sub Form_Load()
Set cn = New ADODB.Connection
cn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & App.Path & "\\db1.mdb"
cn.CursorLocation = adUseClient
cn.Open
Set rsCD = New ADODB.Recordset
SQLString = "Select strUserID as 原因 , strUserModel as 消費 from tabcar where val(strUserID) >= 4 "
rsCD.Open SQLString, cn, adOpenStatic, adLockOptimistic
Set dtg.DataSource = rsCD
End Sub

呢條其實係咩意思呢 請在無句後面加上註釋 唔該灑

Answer 1

Private Sub Form_Load()
Set cn = New ADODB.Connection ' 建立cn物件為adoconnection物件
cn.ConnectionString = "Provider=M icrosoft.Jet.OLEDB.4 .0;Data Source=" & App.Path & "\db1.mdb" ' 設定cn 的連線字串, 是用mdac jet engine 4.0, 而該access db是為於該程式碼的同一位置, 而該檔案名稱是db1.mdb.
cn.CursorLocation = adUseClient ' 設定cursor 的方法, 設定為於客戶端執行.
cn.Open ' 開啟資料庫, 亦可當作是連接資料庫.
Set rsCD = New ADODB.Recordset ' 建立rscd為adodb.recordset物件.
SQLString = "Select strUserID as 原因 , strUserModel as 消費 from tabcar where val(strUserID) >= 4 " ' 設定select statement, 而這statement將會是rscd拿取資料的準則.
rsCD.Open SQLString, cn, adOpenStatic, adLockOptimistic ' 以cn 連線, 擷取資料庫的資料, adopenstatic 是指cursortype, 該recordset是複製自資料庫, 而當你更改任何東西, 其他使用者是看不見的, adlockotpimistic代表當執行update時只會lock 會更改的記錄.
Set dtg.DataSource = rsCD ' 設定一datagrid的資料來源為rscd
End Sub