form1.frm

vb与access数据库的操作实例

VERSION 5.00
Begin VB.Form Form1 
   BorderStyle     =   1  'Fixed Single
   Caption         =   "TestFields"
   ClientHeight    =   2415
   ClientLeft      =   45
   ClientTop       =   330
   ClientWidth     =   4590
   LinkTopic       =   "Form1"
   MaxButton       =   0   'False
   MinButton       =   0   'False
   ScaleHeight     =   2415
   ScaleWidth      =   4590
   StartUpPosition =   2  '屏幕中心
   Begin VB.CommandButton Command1 
      Caption         =   "关 闭"
      Height          =   495
      Left            =   1628
      TabIndex        =   1
      Top             =   1680
      Width           =   1335
   End
   Begin VB.Label Label1 
      AutoSize        =   -1  'True
      Caption         =   "此实例用来演示Fields集合的功能"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   240
      Left            =   360
      TabIndex        =   0
      Top             =   480
      Width           =   3870
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub Command1_Click()
  Unload Me
End Sub

Private Sub Form_Load()
  '创建Connection对象cnn，关键New用于创建新对象
  Dim cnn As New ADODB.Connection
  '创建Recordset对象rs1
  Dim rs1 As New ADODB.Recordset
  '设置查询记录集的SQL语句
  Dim varSource As String
  varSource = "SELECT * FROM Departments ORDER BY DepId"
  
  If Dir(App.Path + "\人事.mdb") <> "" Then
    '设置连接字符串ConnectionString属性
    cnn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" _
               + " Data Source=" + App.Path + "\人事.mdb; "
    '打开到数据库的连接
    cnn.Open
    '设置rs1的ActiveConnection属性，指定与其关联的数据库连接
    Set rs1.ActiveConnection = cnn
    '设置游标类型
    rs1.CursorType = adOpenStatic
    '打开记录集，将从表Departments中读取的结果集保存到记录集rs1中
    rs1.Open varSource
    '显示表HOTELMAN.RoomType的字段数
    MsgBox "表Departments共有 " + Trim(rs1.Fields.Count) + " 个字段"
    '使用循环语句，依次读取各字段的属性值
    i = 0
    Do While i < rs1.Fields.Count
      '显示字段的属性
      MsgBox "第" + Trim(i + 1) + "个字段的名称为:" + Trim(rs1.Fields(i).Name) _
             + Chr(13) + "字段定义长度为:" + Trim(rs1.Fields(i).DefinedSize) _
             + Chr(13) + "字段实际长度为:" + Trim(rs1.Fields(i).ActualSize)
      '如果当前记录存在则显示当前字段的值，否则显示无当前值
      If rs1.EOF = False Then
        MsgBox "此字段的当前值为:" + Trim(rs1.Fields(i).Value)
      Else
        MsgBox "此字段没有当前值"
      End If
      '读取下一个字段
      i = i + 1
    Loop
    
    '关闭记录集
    rs1.Close
    '关闭cnn对象
    cnn.Close
  Else
    MsgBox ("找不到人事数据库")
  End If
End Sub