Question

I’m working on a really simple web service and hoping to get some help. I took the stock web service from Visual Studio, and started modifying it with very limited knowledge of ODP.NET.

Effectively, what I’m trying to do is bring back a set of results from a SQL Query that has a variable in it that I pass to the service. WR_Premise is the variable that I’d like to incorporate, after I get my query working correctly. I call my function using the WCF Test client, but am getting a InvalidOperationException when I try to run the following code.

Public Function GetData(ByVal value As Integer) As String Implements IService1.GetData
        Dim wrpremise As Integer
        Dim state As String
        Dim queryString As String = _
         "select MV_OUTAGE_DURATION.CAUSE_DESC, MV_OUTAGE_DURATION.DEV_NAME, MV_OUTAGE_DURATION.DEV_TYPE_NAME, MV_OUTAGE_DURATION.EVENTNUM, MV_OUTAGE_DURATION.OUT_MINUTES, MV_OUTAGE_DURATION.OFF_DTS , MV_OUTAGE_DURATION.RESTORE_DTS , MV_OUTAGE_DURATION.SYS_RESP_TYPE from MV_we_outage_premise, MV_OUTAGE_DURATION where mv_we_outage_premise.evntnum = MV_OUTAGE_DURATION.eventnum and mv_we_outage_premise.we_premise = '995184' order by(MV_OUTAGE_DURATION.RESTORE_DTS)"
        Dim command As New OracleCommand(queryString)

    value = wrpremise

    Dim oradb As String = "Data Source=****;User Id=******;Password=***********;"
    Dim conn As New OracleConnection(oradb)
    conn.Open()
    state = conn.State.ToString()

    command.ExecuteNonQuery()

    MsgBox(state)
    conn.Close()
    state = conn.State.ToString()
    MsgBox(state)

    Return String.Format("You entered: {0}", value)
End Function

I can get the service to work and return the states when I take the command.ExecuteNonQuery() out of the service, but that doesn’t help me out much…
Also, anyone know an easy way to output the results to XML?

Answer 1

Two problems in your query

• First, the command is not associated to the connection
• Second, you are retrieving records, so your should use a DataReader
  or a DataAdapter to fill a DataTable

For the command connection use

    command.Connection = conn

For the retrieving records

    Dim reader as OracleDataReader = command.ExecuteReader()
    while (reader.Read())
    {
        ... use your data         
    }

See here a reference on a OracleDataReader and here for a OraclaDataAdapter