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HomeDatabaseMysql TutorialVB.net数据库编程(03):一个SQLserver连接查询的简单例子

这个例子,由于在ADO.net入门已经专门学了,再次进行复习 一下。 主要掌握连接字串的情况。 过程就是: 1、引用System.Data.SqlClient。而Access中引用 的是System.Data.OleDB.所以是有区别的 2、相关连接、适配器、数据集。 3、DataGridView绑定显示。 连接

这个例子,由于在ADO.net入门已经专门学了,再次进行复习 一下。


主要掌握连接字串的情况。

过程就是:

1、引用System.Data.SqlClient。而Access中引用 的是System.Data.OleDB.所以是有区别的

2、相关连接、适配器、数据集。

3、DataGridView绑定显示。


连接字串如下:

Data Source                     IP地址或计算名(数据库所在位置的),如果是本地计算机可以用(local)或直接用.来代替,或者本地IP:127.0.0.1代替。

Initial  Catalog                  数据库名

Integrated Security      安全连接情况(真或假),若是Windows验证方式则为真,若是用户名及密码登录则为假。

User ID                         上项为假时,提供用户名

Password                     ...................,提供密码。


因此,就上面五项就瓮中保证了字串。

如:本地上Sales数据库,用户名为sa,密码为123456,各项之间用分号隔开,则字串为如下:

Data Source=(Local);Initial Catalog=Sales;Integrated Security=False;User ID=sa;Password=123456;

因为在本地所以用了(Local),还可直接用点号来代替,同时若本地计算机名为Zheng,还可用Zheng。


下面正题:

在SQlServer2012中建立一个Sales数据库,再在其中建立一个表grade.情况如下:

VB.net数据库编程(03):一个SQLserver连接查询的简单例子



打开VS2012,建立一个窗体,添加一DataGridView控件,双击窗体建立代码:

Imports System.Data.SqlClient

Public Class Form1
    Dim cn As SqlConnection
    Dim da As SqlDataAdapter
    Dim ds As DataSet
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim cnStr As String = "Data Source=(local);Initial Catalog=Sales;Integrated Security=False;User ID=sa;Password=123456;"
        cn = New SqlConnection(cnStr)
        da = New SqlDataAdapter("select * from grade", cn)
        ds = New DataSet()
        da.Fill(ds, "grade")
        DataGridView1.DataSource = ds.Tables("grade")
    End Sub
End Class

运行结果如下:

VB.net数据库编程(03):一个SQLserver连接查询的简单例子


本例只须记住SQlserver连接时,连接字串的“5个”关键值就行了。



===================================================


细节:

da.Fill(ds, "xxx")
DataGridView1.DataSource = ds.Tables("xxx")

这两句的xxx表示表名,  这个表名与原数据库的表名可以不一样。

因为这里是DataSet结果集中的表了,不是原数据库中的,用户自己定义的表名,因此可以任意命名,但这两名应保持一致。


一般都不会自己 再定义,如果有特殊情况时,这个自定义情况就可发挥作用。


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