vb.net数据库 vbnet数据库图书管理系统
vb.net 怎么操作数据库
如果楼主熟悉VB6，可以直接在项目中添加ADODB的Com引用，这样你就可以像VB6那样操作数据库了！
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另外
.NET
Framework中连接数据库要用到ADO.NET。如果要操作Access数据库，要用到System.Data.OleDb命名空间下的许多类。
比如按楼主所说，“我想在textbox1中显示表一中【一些数据】字段下的第一个内容”：
'首先导入命名空间
Imports
System.Data
Imports
System.Data.OleDb
'然后在某一个事件处理程序中写：
Dim
conn
As
New
OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data
Source=数据库.accdb;Jet
OLEDB:Database
Password=MyDbPassword")
Dim
command
As
New
OleDbCommand("Select
*
From
数据表",
conn)
conn.Open()
'打开数据库连接
Dim
reader
As
OleDbDataReader
=
command.ExecuteReader()
'执行SQL语句，返回OleDbDataReader
对象
Do
While
reader.Read()
'读取一条数据
textbox1.Text
+=
reader("一些数据")
VbCrLf
Loop
reader.Close()
'关闭OleDbDataReader
conn.Close()
'关闭连接
vb.nettsql数据库查询数据表不存在
系统bug，网络问题。
1、系统bug是vb.nettsql数据库软件系统出现了问题导致数据表不存在，等待官方修复即可。
2、网络问题是自身设备连接的网络出现较大波动，导致vb.nettsql数据库软件不存在，更换网络重新打开即可。
vb.net 中如何使用SQL语句查询数据库中的数据
1、首先打开Visual Studio 2008代码窗口，添加引用。
2、输入以下代码：Public conn1 As SqlConnection = New SqlConnection 。
3、声明关键字 Public；（因为是全局变量，所以用Public 来声明）。
4、如果SQL 数据库就在本机，则用以下代码连接。
5、如果代码太长，影响可读性，可以用空格加"_"后，回车换行即可。
vb.net数据库操作
参考一下下面这段代码就可以了。
Imports System.Data
'引入数据库操作类命名空间
Imports System.Data.OleDb
'引入ADO.NET操作命名空间
Public Class FrmModifystInfo
Inherits System.Windows.Forms.Form
Public ADOcmd As OleDbDataAdapter
Public ds As DataSet = New DataSet()
'建立DataSet对象
Public mytable As Data.DataTable
'建立表单对象
Public myrow As Data.DataRow
'建立数据行对象
Public rownumber As Integer
'定义一个整型变量来存放当前行数
Public SearchSQL As String
Public cmd As OleDbCommandBuilder
'======================================================
#Region " Windows 窗体设计器生成的代码 "
#End Region
'======================================================
Private Sub FrmModifystInfo_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
'窗体的载入
TxtSID.Enabled = False
TxtName.Enabled = False
ComboSex.Enabled = False
TxtBornDate.Enabled = False
TxtClassno.Enabled = False
TxtRuDate.Enabled = False
TxtTel.Enabled = False
TxtAddress.Enabled = False
TxtComment.Enabled = False '设置信息为只读
Dim tablename As String = "student_Info "
SearchSQL = "select * from student_Info "
ExecuteSQL(SearchSQL, tablename) '打开数据库
ShowData() '显示记录
End Sub
Private Sub ShowData()
'在窗口中的textbox中显示数据
myrow = mytable.Rows.Item(rownumber)
TxtSID.Text = myrow.Item(0).ToString
TxtName.Text = myrow.Item(1).ToString
ComboSex.Text = myrow.Item(2).ToString
TxtBornDate.Text = Format(myrow.Item(3), "yyyy-MM-dd ")
TxtClassno.Text = myrow.Item(4).ToString
TxtTel.Text = myrow.Item(5).ToString
TxtRuDate.Text = Format(CDate(myrow.Item(6)), "yyyy-MM-dd ")
TxtAddress.Text = myrow.Item(7).ToString
TxtComment.Text = myrow.Item(8).ToString
End Sub
Private Sub BtFirst_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtFirst.Click
'指向第一条数据
rownumber = 0
ShowData()
End Sub
Private Sub BtPrev_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtPrev.Click
'指向上一条数据
BtNext.Enabled = True
rownumber = rownumber - 1
If rownumber 0 Then
rownumber = 0 '如果到达记录的首部，行号设为零
BtPrev.Enabled = False
End If
ShowData()
End Sub
Private Sub BtNext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtNext.Click
'指向上一条数据
BtPrev.Enabled = True
rownumber = rownumber + 1
If rownumber mytable.Rows.Count - 1 Then
rownumber = mytable.Rows.Count - 1 '判断是否到达最后一条数据
BtNext.Enabled = False
End If
ShowData()
End Sub
Private Sub BtLast_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtLast.Click
'指向最后一条数据
rownumber = mytable.Rows.Count - 1
ShowData()
End Sub
Private Sub BtDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtDelete.Click
mytable.Rows.Item(rownumber).Delete() '删除记录
If MsgBox( "确定要删除改记录吗？ ", MsgBoxStyle.OKCancel + vbExclamation, "警告 ") = MsgBoxResult.OK Then
cmd = New OleDbCommandBuilder(ADOcmd)
'使用自动生成的SQL语句
ADOcmd.Update(ds, "student_Info ")
BtNext.PerformClick()
End If
End Sub
Private Sub BtModify_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtModify.Click
TxtSID.Enabled = False '关键字段只读
TxtName.Enabled = True '可读写
ComboSex.Enabled = True
TxtBornDate.Enabled = True
TxtClassno.Enabled = True
TxtRuDate.Enabled = True
TxtTel.Enabled = True
TxtAddress.Enabled = True
TxtComment.Enabled = True
End Sub
Private Sub BtUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtUpdate.Click
If Not Testtxt(TxtName.Text) Then
MsgBox( "请输入姓名！ ", vbOKOnly + vbExclamation, "警告 ")
TxtName.Focus()
Exit Sub
End If
If Not Testtxt(ComboSex.Text) Then
MsgBox( "请选择性别！ ", vbOKOnly + vbExclamation, "警告 ")
ComboSex.Focus()
Exit Sub
End If
If Not Testtxt(TxtClassno.Text) Then
MsgBox( "请选择班号！ ", vbOKOnly + vbExclamation, "警告 ")
TxtClassno.Focus()
Exit Sub
End If
If Not Testtxt(TxtTel.Text) Then
MsgBox( "请输入联系电话！ ", vbOKOnly + vbExclamation, "警告 ")
TxtTel.Focus()
Exit Sub
End If
If Not Testtxt(TxtAddress.Text) Then
MsgBox( "请输入家庭住址！ ", vbOKOnly + vbExclamation, "警告 ")
TxtAddress.Focus()
Exit Sub
End If
If Not IsNumeric(Trim(TxtSID.Text)) Then
MsgBox( "请输入数字学号！ ", vbOKOnly + vbExclamation, "警告 ")
Exit Sub
TxtSID.Focus()
End If
If Not IsDate(TxtBornDate.Text) Then
MsgBox( "出生时间应输入日期格式（yyyy-mm-dd）！ ", vbOKOnly + vbExclamation, "警告 ")
Exit Sub
TxtBornDate.Focus()
End If
If Not IsDate(TxtRuDate.Text) Then
MsgBox( "入校时间应输入日期格式（yyyy-mm-dd）！ ", vbOKOnly + vbExclamation, "警告 ")
TxtRuDate.Focus()
Exit Sub
End If
myrow.Item(0) = Trim(TxtSID.Text)
myrow.Item(1) = Trim(TxtName.Text)
myrow.Item(2) = Trim(ComboSex.Text)
myrow.Item(3) = Trim(TxtBornDate.Text)
myrow.Item(4) = Trim(TxtClassno.Text)
myrow.Item(5) = Trim(TxtTel.Text)
myrow.Item(6) = Trim(TxtRuDate.Text)
myrow.Item(7) = Trim(TxtAddress.Text)
myrow.Item(8) = Trim(TxtComment.Text)
mytable.GetChanges()
cmd = New OleDbCommandBuilder(ADOcmd)
'使用自动生成的SQL语句
ADOcmd.Update(ds, "student_Info ")
'对数据库进行更新
MsgBox( "修改学籍信息成功！ ", vbOKOnly + vbExclamation, "警告 ")
TxtName.Enabled = False
ComboSex.Enabled = False
TxtBornDate.Enabled = False
TxtClassno.Enabled = False
TxtRuDate.Enabled = False
TxtTel.Enabled = False
TxtAddress.Enabled = False
TxtComment.Enabled = False '重新设置信息为只读
End Sub
Private Sub BtCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtCancel.Click
TxtSID.Enabled = False
TxtName.Enabled = False
ComboSex.Enabled = False
TxtBornDate.Enabled = False
TxtClassno.Enabled = False
TxtRuDate.Enabled = False
TxtTel.Enabled = False
TxtAddress.Enabled = False
TxtComment.Enabled = False
End Sub
Public Function ExecuteSQL(ByVal SQL As String, ByVal table As String)
Try
'建立ADODataSetCommand对象
'数据库查询函数
ADOcmd = New OleDbDataAdapter(SQL, "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\student.mdb ")
'建立ADODataSetCommand对象
ADOcmd.Fill(ds, table) '取得表单
mytable = ds.Tables.Item(0) '取得名为table的表
rownumber = 0 '设置为第一行
myrow = mytable.Rows.Item(rownumber)
'取得第一行数据
Catch
MsgBox(Err.Description)
End Try
End Function
End Class
请采纳。
vb.NET 关于数据库的读写 - 高分
Dim da As New OleDb.OleDbDataAdapter（‘’输入2/3/4其中的答案）
Dim ds As New DataSet
da.Fill(ds, "Table1")
Dim dt As DataTable
dt = ds.Tables("Table1")
//2. Cmd.CommandText = "select 序号 from 账号 where 姓名='小李'"
//3. Cmd.CommandText = "select 序号 from 账号 where 姓名='小张'"
//4. Cmd.CommandText = "insert into 账号(姓名,年龄,性别,序号) values('张三','22','男','4')"
DataGridView1.DataSource = dt '建立datagridview来显示资料
myCn.Close()
vb.net 写数据库
你这是向sql后台数据库写数据吗?
sqldataadapter1.update 改须指定有效的updatecommand,我一直没有看到
给你个例子你看吧:
'首先指定有效的UpdateCommand
sqlstr = "insert into Playlist(PlayName,PlayPath)values('" TextBox4.Text.Trim "','" TextBox5.Text.Trim "')"
Module1.Mycommand.CommandText = sqlstr
'增加新一行(此行必须,要不不能与后台同步,并且后面调用update会出错)
Module1.MyDataSet.Tables("Music").Rows.Add()
Module1.MyDataAdaPter.InsertCommand = Module1.Mycommand
Module1.MyDataAdaPter.Update(Module1.MyDataSet, "Music")
MsgBox("增加数据成功！！")
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