在vb.net中向mysql数据库添加记录

Question

I am trying to add record of entered inputs to data table but it's not working. I have tried this.

vb.net

Imports System.Data
Imports System.Configuration
Imports MySql.Data.MySqlClient

Partial Class index
    Inherits System.Web.UI.Page
    Dim con As New MySqlConnection("Data Source=204.11.58.166;port=3306;Initial Catalog=quistaBooking;User Id=my_username;password=my_password ;")

Protected Sub confirmBook_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles confirmBook.Click

            Dim emailID, contactNo, source, destination, duration, distance, fare, datetime, vehicle As String

            emailID = email.Text
            contactNo = contact.Text
            source = txtSource.Text
            destination = txtDestination.Text
            duration = dvDuration.Text
            distance = dvDistance.Text
            datetime = datetimepicker.Text
            vehicle = selectVehicle.SelectedItem.ToString

        Try
            Dim str1 As String = "INSERT INTO logistics ('email', 'contact', 'source', 'destination', 'duration', 'distance', 'dateTime', 'vehicleType') values ('" + emailID + "', '" + contactNo + "', '" + source + "', '" + destination + "', '" + duration + "', '" + datetime + "', '" + vehicle + "')"
            Dim data As MySqlDataReader
            Dim adapter As New MySqlDataAdapter
            Dim command As New MySqlCommand
            command.CommandText = str1
            command.Connection = con
            adapter.SelectCommand = command
            data = command.ExecuteReader
            con.Close()
        Catch ex As Exception
            Response.Write(ex)
        End Try
    End Sub
End Class

Error

System.InvalidOperationException: Connection must be valid and open. at MySql.Data.MySqlClient.MySqlConnection.Throw(Exception ex) at MySql.Data.MySqlClient.MySqlCommand.CheckState() at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() at index.confirmBook_Click(Object sender, EventArgs e) in E:\\MY WEB\\Quista\\Website\\index.aspx.vb:line 58

Can any one help me where I am going wrong?

UPDATED ERROR

MySql.Data.MySqlClient.MySqlException (0x80004005): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''email', 'contact', 'source', 'destination', 'duration', 'distance', 'dateTime',' at line 1 at MySql.Data.MySqlClient.MySqlStream.ReadPacket() at MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId) at MySql.Data.MySqlClient.Driver.GetResult(Int32 statementId, Int32& affectedRows, Int64& insertedId) at MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force) at MySql.Data.MySqlClient.MySqlDataReader.NextResult() at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() at index.confirmBook_Click(Object sender, EventArgs e) in E:\\MY WEB\\Quista\\Website\\index.aspx.vb:line 59

Answer 1

Looking at the SQL query:

"INSERT INTO logistics 
('email', 'contact', 'source', 'destination', 'duration', 'distance', 'dateTime', 'vehicleType')
values ('" + emailID + "', '" + contactNo + "', '" + source + "', '" + destination + "', '" + duration + "', '" + datetime + "', '" + vehicle + "')"

I could already see issues:

• You are quoting the field name, that is syntax error.
• You are not using parametrized queries, that is a security issue but could also be a syntax error as well. for example destination would need quote if it was a string. That is the reason you need to use parameters.

More things:

• Connection was never opened
• data = command.ExecuteReader makes no sense because it is a INSERT there is nothing to read you should be using command.ExecuteNonQuery()

---

The more I look at your code, the more issues I find, I rewrote it for you:

Try
   con.Open()
   command.Connection = con

   command.CommandText = "INSERT INTO logistics (`email`, `contact`, `source`, `destination`, `duration`, `distance`, `dateTime`, `vehicleType`) values  (@emailID, @contactNo, @source, @destination, @duration, @datetime, @vehicle)"
   command.Prepare()
   command.Parameters.AddWithValue("@emailID", emailID)
   command.Parameters.AddWithValue("@contactNo", contactNo)
   command.Parameters.AddWithValue("@source", source)
   command.Parameters.AddWithValue("@destination", destination)
   command.Parameters.AddWithValue("@duration", duration)
   command.Parameters.AddWithValue("@datetime", datetime)
   command.Parameters.AddWithValue("@vehicle", vehicle)
   command.Parameters.AddWithValue("@text", "One")
   command.ExecuteNonQuery()
Catch ex As MySqlException
    MessageBox.Show("Error " & ex.Number & " has occurred: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try

Answer 2

Connection must be valid and open

Add con.Open() before data = command.ExecuteReader

You have an error in your SQL syntax

You have 8 fields and try insert only 7 values. Missing value distance .