How to call Oracle stored procedure which returns ref cursor

Question

I am trying to call Oracle stored procedure which returns ref cursor, and i need to generate tree view from that returned data. I am new at this and i have two problems.

First problem is that i am not able to call that procedure. I am getting this error: "wrong number or types of arguments in call to 'OBJECT_HIERARCHY'"

And my second problem is that i don't understand how am i gonna get that data when this procedure returns a ref cursor value? There are more then 5000 records in that table and i am not getting that data, but a ref cursor value. Can someone please explain how can i get that data with ref cursor value. I have no experience with Oracle.

This is the procedure definition in oracle:

CREATE OR REPLACE PROCEDURE SAD.object_hierarchy  
(nAppId IN NUMBER,
nParentId IN NUMBER DEFAULT -1, 
o_cRefCursor OUT SYS_REFCURSOR)
IS
BEGIN
IF NOT o_cRefCursor%ISOPEN THEN

  OPEN o_cRefCursor FOR 
     SELECT
        h.PARENT_ID, h.CHILD_ID, h.H_LEVEL,
        o.OBJECT_IDENTIFIER, o.OBJECT_TYPE_ID
     FROM
     (
        SELECT
           PARENT_ID, CHILD_ID, LEVEL AS H_LEVEL
        FROM OBJECT_RELATIONSHIPS
        START WITH PARENT_ID = nParentId --> -1 --= 60170
        CONNECT BY PRIOR CHILD_ID = PARENT_ID
     ) h
     INNER JOIN
        OBJECTS o
        ON
           o.OBJECT_ID = h.CHILD_ID AND
           O.APPLICATION_ID = nAppId;   
 END IF;
END object_hierarchy;

these are the table field definitions

Column Name               Data Type            

 OBJECT_REL_ID            NUMBER (14)                    
 PARENT_ID                NUMBER (14)                    
 CHILD_ID                 NUMBER (14)                    
 OBJECT_IDENTIFIER        VARCHAR2 (255 Byte)    
 OBJECT_TYPE_ID           VARCHAR2 (5 Byte)

and this is my code which returns error:

            string oradb = "Data Source=(DESCRIPTION="
         + "(ADDRESS=(PROTOCOL=TCP)(HOST=tnt33)(PORT=1521))"
         + "(CONNECT_DATA=(SERVICE_NAME=ORCL)));"
         + "User Id=xxx;Password=xxxxx;";
        OracleConnection con = new OracleConnection(oradb);

        try
        {
            con.Open();
            OracleCommand cmd = new OracleCommand();
            cmd.Connection = con;
            cmd.CommandType = System.Data.CommandType.StoredProcedure;
            cmd.CommandText = "SAD.object_hierarchy";
            cmd.Parameters.Add("nAppId", OracleDbType.Int16).Value = 1;
            OracleParameter oraP = new OracleParameter();
            oraP.OracleDbType = OracleDbType.RefCursor;
            oraP.Direction = System.Data.ParameterDirection.Output;
            cmd.Parameters.Add(oraP);
            OracleDataReader reader = cmd.ExecuteReader();

            while (reader.Read())
            {

            }
            reader.Close();    
        }
        catch (Exception ex)
        {

            con.Close();
        }

Can someone please help me and explain to me why is my code returning this error: "wrong number or types of arguments in call to 'OBJECT_HIERARCHY'"

Answer 1

Example:

string connStr = "Data Source=...";
DataSet dataset = new DataSet();

string connStr = ConfigurationManager.ConnectionStrings["OracleConn"].ToString();

using (OracleConnection objConn = new OracleConnection(connStr))
{
    OracleCommand cmd = new OracleCommand();
    cmd.Connection = objConn;
    cmd.CommandText = "Oracle_PkrName.Stored_Proc_Name";
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.Add("Emp_id", OracleType.Int32).Value = 3; // Input id
    cmd.Parameters.Add("Emp_out", OracleType.Cursor).Direction = ParameterDirection.Output;

    try
    {
        objConn.Open();
        cmd.ExecuteNonQuery();
        OracleDataAdapter da = new OracleDataAdapter(cmd);
        da.Fill(dataset);                   
    }
    catch (Exception ex)
    {
        System.Console.WriteLine("Exception: {0}", ex.ToString());
    }
    objConn.Close();
}

Answer 2

If you're going to provide the OUT, you'll need to provide nParentId as well because .NET isn't going to name those parameters when the statement is sent to the server.

cmd.Parameters.Add("nParentId", OracleDbType.Int16).Value = -1;