which would require you to pull back at least four columns.
The modification mentioned in the comments may well get your code to execute but it's not the right way to go. It looks like you tried to use a parameter but failed. Do that but do it right, i.e.
Dim sql As String = "SELECT idstudents, otherColumnsHere FROM students WHERE idstudents = @idstudents"
Using connection As New MySqlConnection(myConnectionString),
command As New MySqlCommand(sql, connection)
command.Parameters.Add("@idstudents", MySqlDbType.Int32).Value = CInt(TextBox1.Text)
conn.Open()
Using reader = command.ExecuteReader()
If reader.Read() Then
TextBox2.Text = reader(1)
TextBox3.Text = reader(2)
TextBox4.Text = reader(3)
End If
End Using
End Using
selamat sore rekan2 semua...
saya mau nanya nih,, gimana ya cara/ code untuk mengecek hasil dari query = NULL...???
saya menggunakan Mysql dan Vb.net 2010.
saya sudah mencoba dengan beberapa code seperti berikut, Namun Code Tersebut Hanya Membaca jika nilai dari querynya tidak NULL alias ada datanya...
code pertama :
Dim strConn As String = "string koneksi kedatabasenya....." conn.ConnectionString = strConn conn.Open()
CMD.Connection = conn
CMD.CommandText = "SELECT idsoal from tbl_soal_tes_seri_angka where substring(idsoal,3,1) ='1' order by idsoal desc"
DR = CMD.ExecuteReader
If DR.HasRows Then
DR.Read()
If DR(0) Is DBNull.Value Then
MessageBox.Show("DATA nya = NULL")
Label7.Text = "11"
ElseIf DR(0) > 0 Then
MessageBox.Show("sudah ada kode soal")
Label7.Text = DR(0)
End If
End If
Code Kedua (Untuk Querynya Sama Yang Dirubah Hanya
bagian pengecekan data NULLnya saja):
While DR.Read()
If DR.IsDBNull(0) Then
MessageBox.Show("Data Nya NULL")
Label7.Text = "11" & "1"
Else
MessageBox.Show("sudah ada kode soal")
Label7.Text = DR(0)
End If
End While
DR.Close()
code ketiga :
If Not IsDBNull(DR(0)) Then
MessageBox.Show("sudah ada kode soal")
Label7.Text = DR(0)
Else
MessageBox.Show("Data Nya NULL")
Label7.Text = "11" & "1"
End If
DR.Close()
Kalo saya coba Querinya dari mysqlnya seperti ini :
Dim connexcel As OleDbConnection Dim daexcel As OleDbDataAdapter Dim dsexcel As DataSet Dim cmdexcel As OleDbCommand Dim drexcel As OleDbDataReader
Dim connodbc As odbcConnection Dim daodbc
As odbcDataAdapter Dim dsodbc As DataSet Dim cmdodbc As odbcCommand Dim drodbc As odbcDataReader
Private Sub import_excel_to_mysql_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Me.CenterToScreen() End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click On Error Resume Next 'OpenFileDialog1.Filter = "(*.xls)|*.xls|(*.xlsx)|*.xlsx|All files (*.*)|*.*"
OpenFileDialog1.ShowDialog() TextBox1.Text = OpenFileDialog1.FileName
Dim dtSheets As DataTable = connexcel.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, Nothing) Dim listSheet As New List(Of String) Dim drSheet As DataRow
For Each drSheet In dtSheets.Rows
listSheet.Add(drSheet("TABLE_NAME").ToString()) Next
For Each sheet As String In listSheet ListBox1.Items.Add(sheet) Next
End Sub
Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged daexcel = New OleDbDataAdapter("select * from [" & ListBox1.Text & "]", connexcel) dsexcel = New DataSet daexcel.Fill(dsexcel) DGV.DataSource = dsexcel.Tables(0)
DGV.ReadOnly = True End Sub
Sub Koneksimysql() connodbc = New OdbcConnection("Driver=MySQL ODBC 5.1 Driver; SERVER=localhost; UID=root;DATABASE=importfromexcel;PORT=3306") connodbc.Open() End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
For baris As Integer = 0 To DGV.RowCount - 2 Call Koneksimysql() Dim simpan As String = "insert into hasilimport values('" &
DGV.Rows(baris).Cells(0).Value & "','" & DGV.Rows(baris).Cells(1).Value & "')" cmdodbc = New OdbcCommand(simpan, connodbc) cmdodbc.ExecuteNonQuery() Next MsgBox("data berhasil disimpan") DGV.Columns.Clear() End Sub