Execute an oracle Function that returns a reference cursor in C#

Question

I have an oracle package with a procedure that has a in out reference cursor. My understanding is that this is pretty standard.

What I didn\'t like is the fact that

Answer 1

I know this is quite an old post, but since it took me so long to figure out all of the minutia involved in getting .NET to "fight nice" with Oracle, I figured I'd put this advice out there for anyone else in this sticky situation.

I frequently call Oracle stored procedures that return a REF_CURSOR in our environment (.NET 3.5 against Oracle 11g). For a function, you can indeed name the parameter anything you'd like, but then you need to set its System.Data.ParameterDirection = ParameterDirection.ReturnValue then ExecuteNonQuery against the OracleCommand object. At that point the value of that parameter will be the ref_cursor that the Oracle function returned. Just cast the value as an OracleDataReader and loop through the OracleDataReader.

I'd post the full code, but I wrote the data access layer in VB.NET years ago, and the bulk of the code consuming the data access layer (our corporate intranet) is in C#. I figured mixing languages in a single response would be the larger faux pas.

Answer 2

I have not tested this with a function, but for my stored procedures. I specify the out parameter for the refCursor.

command.Parameters.Add(new OracleParameter("refcur_questions", OracleDbType.RefCursor, ParameterDirection.Output));

If you are able to get the function to work with the CommandType.Text. I wonder if you can try adding the parameter above except with the direction as:

ParameterDirection.ReturnValue

I am using Oracle.DataAccess version 2.111.6.0

Answer 3

I had to go up and down between the question and answers to figure out the full code that works. So I am giving the full code here that worked for me for others -

var sql = @"BEGIN :refcursor1 := mypackage.myfunction(:param1) ; end;";
using(OracleConnection con = new OracleConnection("<connection string>"))
using(OracleCommand com = new OracleCommand())
{
     com.Connection = con;
     con.Open();
     com.Parameters.Add(":refcursor1", OracleDbType.RefCursor, ParameterDirection.Output);
     com.Parameters.Add(":param1", "param");
     com.CommandText = sql;
     com.CommandType = CommandType.Text;
     com.ExecuteNonQuery();
     OracleRefCursor curr = (OracleRefCursor)com.Parameters[0].Value;
     using(OracleDataReader dr = curr.GetDataReader())
     {
         if(dr.Read())
         {
             var value1 = dr.GetString(0);
             var value2 = dr.GetString(1);
         }
     }
 }

Hope it helps.