VB.net连接数据库创建新字段并对其进行赋值

首先打开数据源，然后使用alter table语句即可，具体范例如下：

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Set cn = New ADODB.ConnectionSet rs = New ADODB.Recordsetconstr = "DRIVER=Microsoft Access Driver (*.mdb);DBQ=" 数据库路径及文件名 ""cn.Open constrDim str As Stringstr = "alter table 表名 add 字段 类型"rs.Open str, cn, adOpenStaticmsgbox"添加字段成功",vbokonly

VB.NET通过调用模块怎么建立access数据库?

oledb的使用网上的确很多.\x0d\x0a如果只是查询. 写入. 删除,我们常用的就是\x0d\x0aOleDbConnection '用于写数据库的连接\x0d\x0aOleDbCommand '用于数据的操作 接收SQL语句 并执行\x0d\x0aOleDbDataReader '查询了,我们就用这个类来读取查询的对象\x0d\x0a1).OleDbConnection \x0d\x0a dim conn as new OleDbConnection("Provider = Microsoft.Jet.OLEDB.4.0;Data Source =数据库的路径")'连接字符串一般就这样 \x0d\x0a 查询前在打开 \x0d\x0a conn.open\x0d\x0a 2).OleDbCommand \x0d\x0a dim cmd as new OleDbCommand ("SQL语句",conn)'SQL语句决定了你是查询写入还是更新删除\x0d\x0a '''\x0d\x0a如果是查询,你还要用到OleDbDataReader \x0d\x0a 这个是不用新建的不能用New \x0d\x0adim rd as OleDbDataReader=cmd.ExecuteReader'cmd.ExecuteReader 方法就是读取查询的内容\x0d\x0acmd.ExecuteNonQuery用于执行操作 返回变动的条数 ,一般用于 添加 删除 更新 等其它操作\x0d\x0a \x0d\x0a其实就这些了,就是要学点SQL语句就行了.\x0d\x0a标准执行过程就是\x0d\x0a Dim conn As New OleDbConnection("连接字符串")\x0d\x0a conn.Open()\x0d\x0a Dim cmd As New OleDbCommand("SQL语句", conn)\x0d\x0a '如果是写入 更新 删除 则\x0d\x0a cmd.ExecuteNonQuery()\x0d\x0a 否则\x0d\x0a Dim rd As OleDbDataReader = cmd.ExecuteReader\x0d\x0a \x0d\x0a If rd.Read Then\x0d\x0a Dim d As Object = rd.Item("字段名")\x0d\x0a End If\x0d\x0a 结束如果\x0d\x0a rd.Close()\x0d\x0a cmd.Dispose()\x0d\x0a conn.Close()\x0d\x0a \x0d\x0a上面要有 Imports System.Data.OleDb

vb.net 创建ACCESS数据库。大神给点代码，学习学习。

这也是我研究很长时间的成果，差不多分得给我吧。\(^o^)/~

Imports System.Data

Public Class Form1

Public dt As New DataTable

Public dr As DataRow

'内存表格及界面表格初始化，分类列表框初始化

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Me.SetDesktopBounds(283, 84, 800, 600)

With dt

.Clear()

.Columns.Add("ID")

.Columns.Add("故障描述")

.Columns.Add("原因分析")

.Columns.Add("排除办法")

.Columns.Add("备注")

.Columns.Add("时间")

End With

With Me.DataGridView1

.DataSource = dt

.Columns(0).Width = 30

.Columns(1).Width = 120

.Columns(2).Width = 150

.Columns(3).Width = 190

.Columns(4).Width = 65

.Columns(5).Width = 150

End With

With TS_ComboBox1

.Items.Clear()

.Items.Add("电气")

.Items.Add("机械")

.Items.Add("操作")

End With

End Sub

'将表格中的数据显示到文本框中

Private Sub DataGridView1_CellMouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellMouseEventArgs) Handles DataGridView1.CellMouseClick

If Not IsDBNull(DataGridView1.CurrentRow.Cells(1).Value) Then

RichTextBox1.Text = DataGridView1.CurrentRow.Cells(1).Value

End If

If Not IsDBNull(DataGridView1.CurrentRow.Cells(2).Value) Then

RichTextBox2.Text = DataGridView1.CurrentRow.Cells(2).Value

End If

If Not IsDBNull(DataGridView1.CurrentRow.Cells(3).Value) Then

RichTextBox3.Text = DataGridView1.CurrentRow.Cells(3).Value

End If

If Not IsDBNull(DataGridView1.CurrentRow.Cells(4).Value) Then

RichTextBox4.Text = DataGridView1.CurrentRow.Cells(4).Value

End If

End Sub

Private Sub MenuItem5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem5.Click

Dim str

str = MsgBox("您确定要退出系统吗？", vbOKCancel + vbQuestion, "系统提示")

If str = vbOK Then

End

End If

End Sub

'查看所有记录

Private Sub MenuItem2_1_1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem2_1_1.Click

Dim strsql

Dim rs As OleDb.OleDbDataReader

strsql = "select * from Fault_Analyse order by ID"

transactsql(strsql)

rs = oledbcmd.ExecuteReader

dt.Clear()

Do Until Not rs.Read() '在这里作为条件的同时，也执行了该语句

dr = dt.NewRow

dr.Item(0) = rs.Item(0)

dr.Item(1) = rs.Item(2)

dr.Item(2) = rs.Item(3)

dr.Item(3) = rs.Item(4)

dr.Item(4) = rs.Item(5)

dr.Item(5) = rs.Item(1)

dt.Rows.Add(dr)

Loop

DataGridView1.Refresh()

oledbcmd.Dispose() '释放后不能读值

dbconnection.Close()

dbconnection.Dispose()

End Sub

'工具栏隐藏与显示操作

Private Sub MenuItem3_1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem3_1.Click

If Me.MenuItem3_1.Checked = True Then

Me.MenuItem3_1.Checked = False

Else

Me.MenuItem3_1.Checked = True

End If

If Me.MenuItem3_1.Checked = True Then

ToolStrip1.Visible = True

Else

ToolStrip1.Visible = False

End If

End Sub

'往Access数据库中插入新行

Private Sub ToolStripButton1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton1.Click

Dim strsql As Object

Dim rs As OleDb.OleDbDataReader

Dim datetime As Date

Dim describe_fault, analyse_reason, solution, remarks As String

Dim class_g1, class_g2 As String

Dim i, j As Integer

i = 0 '初始化

describe_fault = RichTextBox1.Text

analyse_reason = RichTextBox2.Text

solution = RichTextBox3.Text

remarks = RichTextBox4.Text

class_g1 = TS_ComboBox1.Text

class_g2 = TS_ComboBox2.Text

datetime = Now

'注意格式

strsql = "select ID from Fault_Analyse" 'where ID =" + ID + ""

transactsql(strsql)

rs = oledbcmd.ExecuteReader

Do Until Not rs.Read() '获取记录的行数

i = i + 1

Loop

If i = 0 Then i = 1

For j = 1 To i '查询表中是否有ID为j的记录，没有记录则定义新行j

strsql = "select ID from Fault_Analyse where ID =" + CStr(j) + ""

transactsql(strsql)

rs = oledbcmd.ExecuteReader

If Not rs.Read() Then

Num1.Value = CInt(j)

Exit For

End If

Next

If TS_ComboBox1.Text "" And TS_ComboBox2.Text "" Then

strsql = "Insert into Fault_Analyse values('" + CStr(j) + "','" + datetime + " ','" _

+ describe_fault + " ','" + analyse_reason + " ','" + solution + " ','" _

+ remarks + "','" + class_g1 + "','" + class_g2 + "','0')"

transactsql(strsql)

oledbcmd.Dispose() '释放后不能读值

dbconnection.Close()

dbconnection.Dispose()

Else

MsgBox("请为输入的内容分类。", vbOK + vbInformation, "系统提示")

End If

End Sub

'从数据库中删除选中行

Private Sub ToolStripButton3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton3.Click

Dim strsql

Dim str

str = MsgBox("确定要删除- " + CStr(RichTextBox1.Text) + " -的内容吗？", vbOKCancel + vbQuestion, "系统提示")

If str = vbOK Then

strsql = "delete from Fault_Analyse where describe_fault='" + CStr(RichTextBox1.Text) + "'"

transactsql(strsql)

oledbcmd.Dispose() '释放后不能读值

dbconnection.Close()

dbconnection.Dispose()

End If

End Sub

'按照分类查询数据库中指定内容

Private Sub ToolStripButton4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton4.Click

Dim strsql

Dim rs As OleDb.OleDbDataReader

If TS_ComboBox1.Text = "" Or TS_ComboBox2.Text = "" Then

MsgBox("请选择您要查询的类别", vbOKCancel + vbInformation, "系统提示")

Else

strsql = "select * from Fault_Analyse where class_g1='" _

+ TS_ComboBox1.Text + "'and class_g2='" + TS_ComboBox2.Text + "' order by ID"

transactsql(strsql)

rs = oledbcmd.ExecuteReader

dt.Clear()

Do Until Not rs.Read() '在这里作为条件的同时，也执行了该语句

dr = dt.NewRow

dr.Item(0) = rs.Item(0)

dr.Item(1) = rs.Item(2)

dr.Item(2) = rs.Item(3)

dr.Item(3) = rs.Item(4)

dr.Item(4) = rs.Item(5)

dr.Item(5) = rs.Item(1)

dt.Rows.Add(dr)

Loop

DataGridView1.Refresh()

oledbcmd.Dispose() '释放后不能读值

dbconnection.Close()

dbconnection.Dispose()

End If

End Sub

'界面文本框内容清空

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim str

str = MsgBox("确定要清空文本框中内容吗？", vbOKCancel + vbQuestion, "系统提示")

If str = vbOK Then

RichTextBox1.Text = " "

RichTextBox2.Text = " "

RichTextBox3.Text = " "

RichTextBox4.Text = " "

End If

End Sub

'分类选择列表框的定义

Private Sub TS_ComboBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles TS_ComboBox1.TextChanged

TS_ComboBox2.Text = ""

If TS_ComboBox1.Text = "电气" Then

With TS_ComboBox2.Items

.Clear()

.Add("程序")

.Add("设备")

.Add("方案")

.Add("工艺")

.Add("其它")

End With

ElseIf TS_ComboBox1.Text = "机械" Then

With TS_ComboBox2.Items

.Clear()

.Add("设计")

.Add("质量")

.Add("故障")

.Add("其它")

End With

ElseIf TS_ComboBox2.Text = "操作" Then

With TS_ComboBox2.Items

.Add("熟练度")

.Add("方案")

.Add("其它")

End With

End If

End Sub

'工具栏的显示与隐藏

Private Sub ToolStripButton5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton5.Click

MenuItem3_1.Checked = False

ToolStrip1.Visible = False

End Sub

End Class

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