Question

I am pretty sure this is a basic syntax error, I am new at this and basically figuring things out by trial and error… I am trying to insert data from textboxes into an Access database, where the primary key fields in tableCourse are prefix and course_number. It keeps giving me the “no value given for one or more required parameters” error. Here is my codebehind:

Protected Sub Wizard1_FinishButtonClick(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.WizardNavigationEventArgs) Handles Wizard1.FinishButtonClick
    'Collect Data
    Dim myDept = txtDept.Text
    Dim myFirst = txtFirstName.Text
    Dim myLast = txtLastName.Text
    Dim myPrefix = txtCoursePrefix.Text
    Dim myNum = txtCourseNum.Text

    'Define Connection
    Dim myConn As New OleDbConnection
    myConn.ConnectionString = AccessDataSource1.ConnectionString

    'Create commands
    Dim myIns1 As New OleDbCommand("INSERT INTO tableCourse (department, name_first, name_last, prefix, course_number) VALUES (@myDept, @myFirst, @myLast, @myPrefix, @myNum)", myConn)

    'Execute the commands
    myConn.Open()
    myIns1.ExecuteNonQuery()
End Sub

EDIT: I have parameters inside of my AccessDataSource, is there a way to use those? Sorry if that’s a stupid question, I’m still learning this stuff and it really confuses me…

EDIT: Not really sure which answer to use, lol… I tried this:

Dim myIns1 As New OleDbCommand("INSERT INTO tableCourse (department, name_first, name_last, prefix, course_number) VALUES (?, ?, ?, ?, ?)", myConn)

    myIns1.Parameters.AddWithValue("@myDept", myDept)
    myIns1.Parameters.AddWithValue("@myFirst", myFirst)
    myIns1.Parameters.AddWithValue("@myLast", myLast)
    myIns1.Parameters.AddWithValue("@myPrefix", myPrefix)
    myIns1.Parameters.AddWithValue("@myNum", myNum)

And it inserts the data, I checked the database and it’s all there, but it still gives me an error:

“The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship. Change the data in the field or fields that contain duplicate data, remove the index, or redefine the index to permit duplicate entries and try again.”

Answer 1

You need to do something like this:

Protected Sub Wizard1_FinishButtonClick(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.WizardNavigationEventArgs) Handles Wizard1.FinishButtonClick
    'Collect Data
    Dim myDept = txtDept.Text
    Dim myFirst = txtFirstName.Text
    Dim myLast = txtLastName.Text
    Dim myPrefix = txtCoursePrefix.Text
    Dim myNum = txtCourseNum.Text

    'Define Connection
    Dim myConn As New OleDbConnection
    myConn.ConnectionString = AccessDataSource1.ConnectionString

    'Create commands
    Dim myIns1 As New OleDbCommand("INSERT INTO tableCourse (department, name_first, name_last, prefix, course_number) VALUES (@myDept, @myFirst, @myLast, @myPrefix, @myNum)", myConn)

     myIns1.Parameters.AddWithValue("@myDept", myDept)
     myIns1.Parameters.AddWithValue("@myFirst", myFirst)
     myIns1.Parameters.AddWithValue("@myLast", myLast)
     myIns1.Parameters.AddWithValue("@myPrefix", myPrefix)
     myIns1.Parameters.AddWithValue("@myNum", myNum)
    'Execute the commands
    myConn.Open()
    myIns1.ExecuteNonQuery()
End Sub