网络应用与开发2

订装线1、利用command对象的ExecuteScalar()方法读出Sample.mdb数据库中stu_info表的记录总数。

Imports System.DataImports System.Data. OleDb ‘第一空Private Sub insert_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles insert.ClickDim objconn As New OleDbConnection‘第二空objconn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data source=" & Server.MapPath("sample.mdb") ‘第三空objconn. Open() ‘第四空Dim mySQL As String = "select count(*) from stu_info"Dim objCmd As New OleDbCommand(mySQL, objconn)Dim totalrow As Integer = objCmd.ExecuteScalar()‘第五空Response.Write("记录总数为：" & totalrow)objconn.Close()End Sub2、往sample.mdb数据库中stu_info表中插入一条记录，表中字段：学号、姓名、专业。

Imports System.DataImports System.Data. System.Data.OleDb‘第一空Private Sub insert_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles insert.ClickDim objconn As New OleDbConnection‘第二空objconn.ConnectionString = "Provider= Microsoft.Jet.OLEDB.4.0;Data source=" & Server.MapPath("sample.mdb") ‘第三空objconn. Open() ‘第四空Dim mysql As Stringmysql = "insert into stu_info(学号,姓名,专业) values('1001','王红','计算机应用')"Dim objcmd As New OleDbCommand(mysql, objconn)objcmd. ExecuteNonQuery()‘第五空objconn.Close()Response.Write("一条记录插入成功")End Sub3、用DataView对象象作为数据列表控件（DataGrid对象）的数据源，显示Sample.mdb 数据库中Stu_info表的信息。

操作如下：添加Sample.mdb到项目中，插入DataGrid控件，属性均为默认，代码如订装线下：Imports System.DataImports System.Data.OleDbPrivate Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.LoadIf Not Page.IsPostBack ThenDim objconn As New OleDbConnectionobjconn.ConnectionString = "Provider=Microsoft.JET.OLEDB.4.0;Data source=" & Server.MapPath("sample.mdb")Dim mysql As Stringmysql = "select * from stu_info"Dim myda As New OleDbDataAdapter (mysql, objconn)‘第一空'声明一个DataSetDim myds As New DataSet‘第二空 '用DataAdapter的FILL方法填充DataSetmyda.Fill(myds, "学生信息表")'定义DataView对象Dim mydv As DataViewmydv = myds.Tables("学生信息表").DefaultView‘第三空DataGrid1.DataSource = mydv ‘第四空DataGrid1. DataBind()‘第五空End IfEnd Sub4、通过DataAdapter对象获取数据库Sample.mdb中表Stu_info中的记录，并填充到DataSet对象中。

Imports System.DataImports System.Data.OleDbPrivate Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.LoadIf Not Page.IsPostBack Then ‘第一空Dim objconn As New OleDbConnection'设置链接字符串objconn.ConnectionString = "Provider=Microsoft.JET.OLEDB.4.0;Data source=" &Server.MapPath("sample.mdb")‘第二空Dim mysql As Stringmysql = "select * from stu_info"订装线'建立DataAdapter对象，并且指定SQL语句Dim myda As New OleDbDataAdapter (mysql, objconn) ‘第三空Dim myds As New DataSet()‘第四空myda. Fill (myds, "stu_info") ‘第五空Response.Write("数据集对象dataset已被填充")End IfEnd Sub5、通过DataAdapter对象获取数据库Sample.mdb中表Stu_info，Teacher_info，Coerse_info中的记录，并填充到DataSet对象中Imports System.DataImports System.Data.OleDbPrivate Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load'在此处放置初始化页的用户代码If Not Page.IsPostBack Then‘第一空Dim objconn As New OleDbConnection'设置链接字符串objconn.ConnectionString = "Provider=Microsoft.JET.OLEDB.4.0;Data source=" & Server.MapPath("sample.mdb")‘第二空objconn.Open()Dim mysql As Stringmysql = "select * from stu_info"'建立第一张表'建立DataAdapter对象，并且指定SQL语句Dim myda As New OleDbDataAdapter(mysql, objconn)Dim myds As New DataSetmyda.Fill(myds, "学生信息表")'建立第二张表mysql = "select * from teacher_info"myda = New oleDbDataAdapter (mysql, objconn)‘第三空 myda.Fill(myds, "教师信息表")'建立第三张表mysql = "select * from course_info"myda = New OleDbDataAdapter(mysql, objconn)myda. Fill (myds, "课程信息表") ‘第四空'输出三个表的表名订装线 Dim i As IntegerFor i = 0 To myds.Tables.Count-1‘第五空 Response.Write(myds.Tables(i).TableName)Response.Write("<p>")Nextobjconn.Close()End IfEnd Sub6、用DataView对象象作为数据列表控件（DataGrid对象）的数据源，显示Sample.mdb 数据库中Stu_info表的信息。

操作如下：添加Sample.mdb到项目中，插入DataGrid控件，属性均为默认，代码如下：Imports System.DataImports System.Data.OleDbPrivate Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.LoadIf Not Page.IsPostBack ThenDim objconn As New OleDbConnectionobjconn.ConnectionString = "Provider=Microsoft.JET.OLEDB.4.0;Data source=" & Server.MapPath("sample.mdb")Dim mysql As Stringmysql = "select * from stu_info"Dim myda As New oleDbDataAdapter (mysql, objconn)‘第一空'声明一个DataSetDim myds As New DataSet ‘第二空'用DataAdapter的FILL方法填充DataSetmyda.Fill(myds, "学生信息表")'定义DataView对象Dim mydv As DataViewmydv = myds.Tables("学生信息表"). DefaultView‘第三空DataGrid1. DataSource = mydv ‘第四空DataGrid1. DataBind() ‘第五空End IfEnd Sub7、新闻管理系统的登录页面：用户名的ID为username，密码的ID为password。