


====================================
General
==== ================================
Connect to the database (just splice the connection database string and call the function):
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()
Verify username and password (that is, take the username and password entered on the interface and match it in the database. If it can be found, pass):
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
Exit (actually Just hide all open windows and display the login window):
For Each f As Form In Application.OpenForms f.Hide() frmLogin.Show() Next
====================== ==============
Customer
============================== =======
Withdrawal:
'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()
Deposit:
'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()
Account inquiry:
'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()
=== ================================
admin
========== ========================
Record operation log:
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()
View all operation logs:
'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
View all user accounts
'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
The above is the content of the VB operation ACCESS example practice question-ATM cash machine code segment. For more related content, please pay attention to the PHP Chinese website (www. php.cn)!

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