建立酒店餐饮管理信息系统,用VB连接用SQL 建立的数据库。数据库已经建立好了,没有问题,但VB运行登录时出现错误:[DBNETLIB][ConnectionOpen(Connect()).]SQL Server 不存在或拒绝访问。源代码是:Private Sub cmdOK_click()
Adodc1.RecordSource = "select * from Table_Users where 用户名='" + Trim(Text1.Text) + "'and 密码='" + Trim(Text2.Text) + "'"
Adodc1.Refresh (显示此处出现错误)
If Adodc1.Recordset.RecordCount > 0 Then
strOk = Adodc1.Recordset.Fields("级别")
If strOk = "系统操作员" Then
frm_main.gkgl.Enabled = True
frm_main.gkxx.Enabled = True
frm_main.gkxxcx.Enabled = True
frm_main.yggl.Enabled = True
frm_main.ygxxgl.Enabled = True
frm_main.ygxxcx.Enabled = True
frm_main.yygl.Enabled = True
frm_main.ycgl.Enabled = True
frm_main.frm_dcd.Enabled = True
frm_main.jzgl.Enabled = True
frm_main.cygl.Enabled = True
frm_main.cd.Enabled = True
frm_main.jclb.Enabled = True
frm_main.cxsz.Enabled = True
frm_main.jcsm.Enabled = True
frm_main.ftgl.Enabled = True
frm_main.ftsz.Enabled = True
frm_main.bmsz.Enabled = True
frm_main.lbsz.Enabled = True
frm_main.xffs.Enabled = True
frm_main.qxgl.Enabled = True
frm_main.yhgl.Enabled = True
frm_main.mmsz.Enabled = True
frm_main.qxsz.Enabled = True
frm_main.sjbf.Enabled = True
frm_main.sjhf.Enabled = True
ElseIf strOk = "普通操作员" Then
frm_main.gkgl.Enabled = True
frm_main.gkxx.Enabled = True
frm_main.gkxxcx.Enabled = True
frm_main.yggl.Enabled = True
frm_main.ygxxgl.Enabled = True
frm_main.ygxxcx.Enabled = True
frm_main.yygl.Enabled = True
frm_main.ycgl.Enabled = True
frm_main.frm_dcd.Enabled = True
frm_main.jzgl.Enabled = True
frm_main.cygl.Enabled = True
frm_main.cd.Enabled = True
frm_main.jclb.Enabled = True
frm_main.cxsz.Enabled = True
frm_main.jcsm.Enabled = True
frm_main.ftgl.Enabled = True
frm_main.ftsz.Enabled = True
frm_main.bmsz.Enabled = True
frm_main.lbsz.Enabled = True
frm_main.xffs.Enabled = True
frm_main.qxgl.Enabled = False
frm_main.yhgl.Enabled = False
frm_main.mmsz.Enabled = False
frm_main.qxsz.Enabled = False
frm_main.sjbf.Enabled = False
frm_main.sjhf.Enabled = False
End If
Unload Me
Load frm_main
frm_main.Show
Else
MsgBox "输入错误,请重新输入!"
Text1.Text = ""
Text2.Text = ""
Text1.SetFocus
Exit Sub
End If
End Sub
1、打开代码窗口,添加引用:Imports System.Data.SqlClient。
2、输入以下代码:
“Public conn1 As SqlConnection = New SqlConnection _
("server=192.168.1.79; Initial Catalog= student; User ID= panqe;PWD=shentai768@")”,vb就已经成功连接sql数据库了。
3、代码详解:声明关键字Public(因为是全局变量,所以用Public 来声明)。
4、连接参数。
5、如果SQL 数据库就在本机,则用以下代码连接:
("server=.; Integrated Security=False;Initial Catalog= student; User ID= panqe;PWD=shentai768@")。
6:如果代码太长,影响可读性,可以用空格加"_"后,回车换行。