vb.net cannot write Query to MSAccess file - sql

Question

i can access to local Access Database and i can add some data using Query, but it JUST shows its data when the program is alive. when I re-execute this program, i cannot see any previously added data and so do original Database file(SourceDB.mdb).
How can I save my data? Here is my code.
Imports System.Data.OleDb
Public Class UserForm
Private myConn As String = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=.\SourceDB.mdb"
Private mDbConn As OleDbConnection
Private Sub Button_Search_Click(sender As Object, e As EventArgs) Handles Button_Search.Click
Dim myAdapter As New OleDbDataAdapter("SELECT * FROM user WHERE u_name = '" + tBoxName.Text + "'", myConn)
Dim myDataTable As New DataTable
If tBoxName.Text = "" Then
MsgBox("Input name")
Else
myAdapter.Fill(myDataTable)
If myDataTable.Rows.Count > 0 Then
tBoxPhone.Text = myDataTable.Rows(0).Item("u_phone")
tBoxAddr.Text = myDataTable.Rows(0).Item("u_addr")
tBoxBName.Text = myDataTable.Rows(0).Item("u_bname")
tBoxBAccount.Text = myDataTable.Rows(0).Item("u_baccount")
tBoxEtc.Text = myDataTable.Rows(0).Item("u_comment")
Else
MsgBox("No Name in Table")
End If
End If
End Sub
Private Sub Button_OK_Click(sender As Object, e As EventArgs) Handles Button_OK.Click
Try
If lblAOE.Text = "Add" Then
Dim myAdapter As New OleDbDataAdapter("INSERT INTO user (u_name, u_phone, u_addr, u_bname, u_baccount, u_comment) VALUES ('" + _
tBoxName.Text + "', '" + tBoxPhone.Text + "', '" + tBoxAddr.Text + "', '" + tBoxBName.Text + _
"', '" + tBoxBAccount.Text + "', '" + tBoxEtc.Text + "')", myConn)
Dim myDataTable As New DataTable
myAdapter.Fill(myDataTable)
Button_Add.Visible = True
Button_Modify.Visible = True
Button_OK.Visible = False
ClearTextBoxes()
Button_Clear.Text = "비우기"
End If Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
Private Sub Button_Delete_Click(sender As Object, e As EventArgs) Handles Button_Delete.Click
If MessageBox.Show("Sure Wanna delete data?", "Delete", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) = DialogResult.No Then
MsgBox("Cancelled")
Exit Sub
Else
Dim myAdapter As New OleDbDataAdapter("DELETE FROM user WHERE u_name = '" + tBoxName.Text + "'", myConn)
Dim myDataTable As New DataTable
myAdapter.Fill(myDataTable)
MsgBox("DELETED")
ClearTextBoxes()
End If
End Sub
Private Sub ClientForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.UserTableAdapter.Fill(Me.SourceDBDataSet.user)
Me.Text = "User Form"
End Sub
End Class

Answer 1

You are using a OleDbDataAdapter trying to execute an INSERT operation (or a DELETE one), but this is not how the OleDbDataAdapter works.
An OleDbDataAdapter uses the SELECT command to retrieve the records and, if defined, its InsertCommand property to update records of a dataset through the call to the OleDbDataAdapter.Update method. You are not in this situation and you have your values directly in the textboxes. You could simply use an OleDbCommand with the appropriate sql statement (and this is the same for your DELETE method)
Try to change your code to
Dim cmdText = "INSERT INTO [user] (u_name, u_phone, u_addr, u_bname, " & _
"u_baccount, u_comment) VALUES (?, ?, ?, ?,?,?)"
Dim cmd = New OleDbCommand(cmdText, myConn)
cmd.Parameters.AddWithValue("#p1",tBoxName.Text)
cmd.Parameters.AddWithValue("#p2",tBoxPhone.Text )
cmd.Parameters.AddWithValue("#p3",tBoxAddr.Text)
cmd.Parameters.AddWithValue("#p4",tBoxBName.Text)
cmd.Parameters.AddWithValue("#p5",tBoxBAccount.Text)
cmd.Parameters.AddWithValue("#p6",tBoxEtc.Text )
cms.ExecuteNonQuery()
I have changed your string concatenation to a more correct parameterized query to avoid Sql Injection and parsing problems in case one of your textbox values contains a single quote.

Answer 2

you use OleDbCommand class. you make class object and use ExecuteNonQuery for insert data
like
Dim o As OleDbCommand
o.Connection = con
o.CommandType = CommandType.Text
o.CommandText = "your Query"
o.ExecuteNonQuery()
and you should use try block
try
o.ExecuteNonQuery()
catch
end try