====================================
通用
====================================
连接数据库（拼接连接数据库字符串，调用函数即可）：
Dim Con As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= ATM.mdb"
Dim connConnection As OleDb.OleDbConnection = New OleDb.OleDbConnection
connConnection.ConnectionString = Con
connConnection.Open()验证用户名密码（就是拿着界面上输入的用户名密码 去数据库里面匹配，如果可以找到就通过）：
Private Function UserIsValid() As Boolean
'连接数据库
Dim Con As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= ATM.mdb"
Dim connConnection As OleDb.OleDbConnection = New OleDb.OleDbConnection
connConnection.ConnectionString = Con
connConnection.Open() '验证一下用户名密码是否存在
Dim strSql As String = "select * from AccountInfo where AccountNo = '" & _
Trim(TextBox1.Text) & "' and Password = '" & Trim(TextBox2.Text) & "'"
Dim connCommand As OleDb.OleDbCommand = New OleDb.OleDbCommand(strSql, connConnection)
Dim myReader As OleDb.OleDbDataReader = connCommand.ExecuteReader
'如果有数据
If myReader.HasRows Then
myReader.Read() '读一行数据到reader里面
If Trim(TextBox1.Text) = myReader(1) And Trim(TextBox2.Text) = myReader(2) Then
connConnection.Close()
Return True
Else
connConnection.Close()
Return False
End If
End If
connConnection.Close()
'没数据直接返回错误
Return False
End Function退出(其实就是把所有打开的窗口都隐藏，把登陆窗口显示就可以了)：
For Each f As Form In Application.OpenForms
f.Hide()
frmLogin.Show()
Next====================================
客户
====================================
取款：
'连接数据库
Dim Con As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= ATM.mdb"
Dim connConnection As OleDb.OleDbConnection = New OleDb.OleDbConnection
connConnection.ConnectionString = Con
connConnection.Open()
'修改金额(存钱)
Dim sql As String = "update AccountInfo set Balance = Balance + " + TextBox1.Text + " where AccountNo = '" + frmLogin.TextBox1.Text + "'"
Dim cmd As OleDb.OleDbCommand = New OleDb.OleDbCommand(sql, connConnection)
cmd.ExecuteNonQuery()
'记录操作日志
sql = "insert into AccountAct (AccountNo,Lastopt,Amount) values ('" & Trim(frmLogin.TextBox1.Text) & "','" & Trim(DateTime.Now.ToString()) & "',
" & CType(TextBox1.Text, Double) & ")"
Dim cmd2 As OleDb.OleDbCommand = New OleDb.OleDbCommand(sql, connConnection)
cmd2.ExecuteNonQuery()
connConnection.Close()存款：
'连接数据库
Dim Con As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= ATM.mdb"
Dim connConnection As OleDb.OleDbConnection = New OleDb.OleDbConnection
connConnection.ConnectionString = Con
connConnection.Open()
'修改金额(取钱)
Dim sql As String = "update AccountInfo set Balance = Balance - " + TextBox2.Text + " where AccountNo = '" + frmLogin.TextBox1.Text + "'"
Dim cmd As OleDb.OleDbCommand = New OleDb.OleDbCommand(sql, connConnection)
cmd.ExecuteNonQuery()
'记录操作日志
sql = "insert into AccountAct (AccountNo,Lastopt,Amount) values ('" & Trim(frmLogin.TextBox1.Text) & "','" & Trim(DateTime.Now.ToString()) & "',
" & CType(TextBox1.Text, Integer) & ")"
cmd = New OleDb.OleDbCommand(sql, connConnection)
cmd.ExecuteNonQuery()
connConnection.Close()查询账户：
'连接数据库
Dim Con As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= ATM.mdb"
Dim connConnection As OleDb.OleDbConnection = New OleDb.OleDbConnection
connConnection.ConnectionString = Con
connConnection.Open()
Dim sql As String = "select Balance from AccountInfo where AccountNo = '" + frmLogin.TextBox1.Text + "'"
Dim cmd As OleDb.OleDbCommand = New OleDb.OleDbCommand(sql, connConnection)
Dim myReader As OleDb.OleDbDataReader = cmd.ExecuteReader
If myReader.HasRows Then
myReader.Read()
Label1.Text = myReader(0)
Else
MessageBox.Show("未找到账户信息")
End If
connConnection.Close()===================================
管理员
==================================
记录操作日志：
sql = "insert into AccountAct (AccountNo,Lastopt,Amount) values ('" & Trim(frmLogin.TextBox1.Text) & "','" & Trim(DateTime.Now.ToString()) & "',
" & CType(TextBox1.Text, Integer) & ")"
cmd = New OleDb.OleDbCommand(sql, connConnection)
cmd.ExecuteNonQuery()
connConnection.Close()查看所有操作日志：
'连接数据库
Dim Con As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= ATM.mdb"
Dim connConnection As OleDb.OleDbConnection = New OleDb.OleDbConnection
connConnection.ConnectionString = Con
connConnection.Open()
'把查询的数据取出来放到data set
Dim strSql As String = "select * from AccountAct"
Dim myDataSet As DataSet = New DataSet()
Dim myAdapter As OleDb.OleDbDataAdapter = New OleDb.OleDbDataAdapter(strSql, connConnection)
myAdapter.Fill(myDataSet, "AccountAct")
connConnection.Close()
'把数据从dataset中取出来显示在控件上()
DataGridView1.DataSource = myDataSet.Tables(0)
DataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells查看所有用户账号
'连接数据库
Dim Con As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= ATM.mdb"
Dim connConnection As OleDb.OleDbConnection = New OleDb.OleDbConnection
connConnection.ConnectionString = Con
connConnection.Open()
'把查询的数据取出来放到data set
Dim strSql As String = "select * from AccountInfo"
Dim myDataSet As DataSet = New DataSet()
Dim myAdapter As OleDb.OleDbDataAdapter = New OleDb.OleDbDataAdapter(strSql, connConnection)
myAdapter.Fill(myDataSet, "AccountInfo")
connConnection.Close()
'把数据从dataset中取出来显示在控件上()
DataGridView1.DataSource = myDataSet.Tables(0)
DataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells 以上就是VB 操作ACCESS 实例 练习题--ATM取款机 代码段的内容，更多相关内容请关注PHP中文网（www.php.cn）！
