我在用VB+aceess做图书管理系统，看到代码不懂，请高手帮忙解释下

来源：百度知道 编辑：UC知道 时间：2024/06/14 05:29:19
Option Explicit
Dim rs_addreader As New ADODB.Recordset

Private Sub Command1_Click()
Dim sql As String
If Trim(Combo1.Text) = "" Then
MsgBox "请选择读者种类", vbOKOnly + vbExclamation, ""
Combo1.SetFocus
Exit Sub
End If
If Trim(Text1.Text) = "" Then
MsgBox "读者姓名不能为空", vbOKOnly + vbExclamation, ""
Text1.SetFocus
Exit Sub
End If
If Trim(Text2.Text) = "" Then
MsgBox "读者编号不能为空", vbOKOnly + vbExclamation, ""
Text2.SetFocus
Exit Sub
End If
sql = "select * from 读者信息 where 读者编号='" & Text2.Text & "'"
rs_addreader.Open sql, conn, adOpenKeyset, adLockPessimistic
If rs_addreader.EOF Then
rs_addreader.AddNew
rs_addreader.Fields(0) = Trim(Text1.Text)
rs_addreader.Fields(1) = Trim(Text2.Text)
rs_addreader.Fields(2) = Trim(Co

If Trim(Combo1.Text) = "" Then
MsgBox "请选择读者种类", vbOKOnly + vbExclamation, ""
Combo1.SetFocus
Exit Sub
End If
If Trim(Text1.Text) = "" Then
MsgBox "读者姓名不能为空", vbOKOnly + vbExclamation, ""
Text1.SetFocus
Exit Sub
End If
If Trim(Text2.Text) = "" Then
MsgBox "读者编号不能为空", vbOKOnly + vbExclamation, ""
Text2.SetFocus
Exit Sub
End If
---------------------------------------------------------上面这些就是输入框不能为空，必须填写！！！！

sql = "select * from 读者信息 where 读者编号='" & Text2.Text & "'"
rs_addreader.Open sql, conn, adOpenKeyset, adLockPessimistic
If rs_addreader.EOF Then
rs_addreader.AddNew
rs_addreader.Fields(0) = Trim(Text1.Text)
rs_addreader.Fields(1) = Trim(Text2.Text)
rs_addreader.Fields(2) = Trim(Combo2.Text)
rs_addreader.Fields(3) = Trim(Combo1