Visual basic (.net) Insert new record question - vb.net

Question

i am a novice, trying to add a new record to a php myadmin database, the secondDB requires an "Id" to be inserted with the data.
the rest of the project uses data bound fileds.
so i generate the new record with
FirstDB.addnew()
secondDB.addnew()
then try to run the below
Call Connection() 'this gets My.Settings.companyConnectionString and opens the connection
Dim str As String = ("SELECT max(Id) FROM FirstDB")
cmd = New MySqlCommand(str, conn)
cmd.CommandType = CommandType.Text
Dim result As Integer = cmd.ExecuteScalar +1 'this will get the number and increase by one
Using cmd As New MySqlCommand()
With cmd
.CommandText = "insert into SecondDB(`id`) values (#id)"
.Parameters.AddWithValue("#id", result)
End With
End Using
conn.Dispose()
also tryed
DataSet.Secondtable.Id.DefaulValue = result
SecondDBbindingSource.Current.item("Id") = result
the secondBD refuses to save without the missing "ID".
if you put the resut in a data bound box it works out fine, but i dont want to have text boxes scatterd around.
can anyone give me some guideance ?

Answer 1

FirstDB.addnew()
secondDB.addnew()
I have no idea what this code is doing.
Call Connection()
Don't do this. Connections need to be declared and disposed in the method where they are used. Using blocks take care of this for us even it there is an error.
Dim str As String = ("SELECT max(Id) FROM FirstDB")
This is not a good way to find the Id you are looking for. In MySql you can add SELECT LAST_INSERT_ID(); to the Insert for FirstDB (terrible name for a table). In a multi-user environment Max will fail.
cmd.CommandType = CommandType.Text
The default type for a command is the Text type so you don't have to explicitly set this property. Interesting that you don't set this property when you create a new command a few lines down.
Dim result As Integer = cmd.ExecuteScalar + 1
ExecuteScalar returns an Object. You cannot add one to an Object. Why do you want to increment this value? The foreign key in secondDB should match the primary key in FirstDB. You said in comments both tables have a primary key field that is auto increment.
.CommandText = "insert into SecondDB(`id`) values (#id)"
Is that all you are entering into the new record? Not a very informative record.
conn.Dispose()
What if an error occurred. Your connection would never be closed or disposed.
DataSet.Secondtable.Id.DefaulValue = result
SecondDBbindingSource.Current.item("Id") = result
I have no idea what you are doing here.
I have to make up a table structure for the 2 tables (not DB, tables).
Private Sub OPCode(Company As String, Contact As String, Address As String)
Dim IdFromFirstDB As Integer
Dim sql = "Insert Into FirstDB (CompanyName, ContactName) Values (#Name, #Contact) Select LAST_INSERT_ID();"
Using cn As New MySqlConnection(My.Settings.companyConnectionString)
Using cmd As New MySqlCommand(sql, cn)
cmd.Parameters.Add("#Name", MySqlDbType.VarChar, 200).Value = Company
cmd.Parameters.Add("#Contact", MySqlDbType.VarChar, 100).Value = Contact
cn.Open()
IdFromFirstDB = CInt(cmd.ExecuteScalar)
End Using
sql = "Insert Into secondDb (Address, CompanyID) Values (#Address, #ID);"
Using cmd As New MySqlCommand(sql, cn)
cmd.Parameters.Add("#Address", MySqlDbType.VarChar, 200).Value = Address
cmd.Parameters.Add("#ID", MySqlDbType.Int32).Value = IdFromFirstDB
cmd.ExecuteNonQuery()
End Using
End Using
End Sub