Insert data from VB net into Postgresql - vb.net

Question

I'm trying to input data from my vb into PostgreSQL
the source is another database on Ms Access
im using this code for connection
Public Function LoadAcces_tblpibconr() As DataTable 'ganti ini sesuai nama table
Dim Table As DataTable = New DataTable()
Command.Connection = conn.OpenConnection()
Command.CommandText = "select * from tblpibconr"
Command.CommandType = CommandType.Text
ReadRows = Command.ExecuteReader()
Table.Load(ReadRows)
ReadRows.Close()
conn.CloseConexion()
Return Table
End Function
'=====================================TABLE POSTGRESQL========================='
Public Function LoadNpgsql_tblpibconr() As DataTable
Dim Table As DataTable = New DataTable()
Cmd.Connection = connNpgsql.OpenConnection()
Cmd.CommandText = "select * from tblpibconr"
Cmd.CommandType = CommandType.Text
ReadRows1 = Cmd.ExecuteReader()
Table.Load(ReadRows1)
ReadRows1.Close()
connNpgsql.CloseConexion()
Return Table
End Function
I'm using this function for filtering the data
I'll compare the data first and take the data without a match and stored it into postgresql
Public Function CekData_tblpibconr(ByVal car As String, ByVal reskd As String, ByVal contno As String) As Boolean
Dim Table As DataTable = New DataTable()
Cmd.Connection = connNpgsql.OpenConnection()
If Cmd.Parameters.Count > 0 Then
Cmd.Parameters.Clear()
End If
Cmd.Parameters.AddWithValue("#car", car)
Cmd.Parameters.AddWithValue("#reskd", reskd)
Cmd.Parameters.AddWithValue("#contno", contno)
Cmd.CommandText = <sql>select * from tblpibconr where car=#car and reskd=#reskd and contno=#contno</sql>.Value
Cmd.CommandType = CommandType.Text
ReadRows1 = Cmd.ExecuteReader() 'ERROR System.InvalidOperationException: 'Parameter '#car' must have its value set'
Table.Load(ReadRows1)
ReadRows1.Close()
If Table.Rows.Count > 0 Then
Return False
Else
Return True
End If
Cmd.Parameters.Clear()
connNpgsql.CloseConexion()
End Function
Sub bandingkan_data_tblpibconr()
For i = 0 To DGV1.Rows.Count - 1
Dim validasi = query.CekData_tblpibconr(DGV1.Rows(i).Cells(0).Value, DGV1.Rows(i).Cells(1).Value, DGV1.Rows(i).Cells(2).Value) 'cek data dari access ke postgresql
If validasi = True Then 'jika data di access tidaj ada
'inser data
Dim a As String
If IsDBNull(DGV1.Rows(i).Cells(4).Value.ToString()) Then
a = "0"
Else
a = DGV1.Rows(i).Cells(4).Value.ToString()
End If
DGV1.Rows(i).DefaultCellStyle.BackColor = Color.MistyRose
Dim Insertdata = query.insertNpgsql_tblpibconr(DGV1.Rows(i).Cells(0).Value.ToString(), DGV1.Rows(i).Cells(1).Value.ToString(), DGV1.Rows(i).Cells(2).Value.ToString() _
, DGV1.Rows(i).Cells(3).Value.ToString(), a)
If Insertdata = True Then
' MsgBox("Masuk")
Else
MsgBox("Data Gagal DIMASUKAN")
End If
End If
Next i
LoadNpgsql_tblpibconr()
MsgBox("Selesai")
End Sub
Public Function insertNpgsql_tblpibconr(ByVal car As String, ByVal reskd As String, ByVal contno As String, ByVal contukur As String, ByVal conttipe As String) As Boolean
Cmd.Connection = connNpgsql.OpenConnection()
If Cmd.Parameters.Count = 0 Then
Cmd.Parameters.Clear()
End If
Try
Cmd.CommandText = "insert into tblpibconr(car,reskd,contno,contukur,conttipe) values(#car,#reskd,#contno,#contukur,#conttipe)"
Cmd.CommandType = CommandType.Text
Cmd.Parameters.AddWithValue("#car", car)
Cmd.Parameters.AddWithValue("#reskd", reskd)
Cmd.Parameters.AddWithValue("#contno", contno)
Cmd.Parameters.AddWithValue("#contukur", contukur)
Cmd.Parameters.AddWithValue("#conttipe", conttipe)
Cmd.ExecuteNonQuery()
str = "insert into tblpibconr(car,reskd,contno,contukur,conttipe) values(#car , #reskd , #contno, #contukur, #conttipe)"
Return True
Catch ex As Exception
MsgBox(ex.Message)
Return False
End Try
connNpgsql.CloseConexion()
End Function
this is the error that I get
System.InvalidOperationException: 'Parameter '#car' must have its
value set'
ITS Refer to ReadRows1 = Cmd.ExecuteReader() on function cekdata_tblpibconr and Dim validasi = query.CekData_tblpibconr(DGV1.Rows(i).Cells(0).Value, DGV1.Rows(i).Cells(1).Value, DGV1.Rows(i).Cells(2).Value) on sub bandingkan_data_tblpibconr
but this error appear after the data successfully inserted to my Postgresql

Answer 1

Before running the Function where the error occurred, I have checked if we really have a value for car.
This method demonstrates what I mean by keeping your database objects local. The connection and command are created locally in a Using block. They will be closed and disposed even it there is an error.
You can pass the connection string directly to the constructor of the connection. Likewise, pass the command text and the connection to the constructor of the command. The default CommandType is CommandType.Text so it is not necessary to explicitly set that property.
Open the connection at the last possible moment directly before the command is executed.
Public Function CekData_tblpibconr(ByVal car As String, ByVal reskd As String, ByVal contno As String) As Boolean
If String.IsNullOrEmpty(car) Then
MessageBox.Show("Car has no value")
Return True '??
End If
Dim Table As DataTable = New DataTable()
Using cn As New NpgsqlConnection(ConStr),
cmd As New NpgsqlCommand("select * from tblpibconr where car=#car and reskd=#reskd and contno=#contno;", cn)
cmd.Parameters.Add("#car", NpgsqlDbType.Varchar).Value = car
cmd.Parameters.Add("#reskd", NpgsqlDbType.Varchar).Value = reskd
cmd.Parameters.Add("#contno", NpgsqlDbType.Varchar).Value = contno
cn.Open()
Table.Load(cmd.ExecuteReader)
End Using
If Table.Rows.Count > 0 Then
Return False
Else
Return True
End If
End Function