at System.Data.OracleClient.Oci.OciStatementHandle.Prepare (System.String commandText) [0x00000] in <filename unknown>:0
  at System.Data.OracleClient.OracleCommand.PrepareStatement (System.Data.OracleClient.Oci.OciStatementHandle statement) [0x00000] in <filename unknown>:0
  at System.Data.OracleClient.OracleCommand.ExecuteReader (CommandBehavior behavior) [0x00000] in <filename unknown>:0
  at System.Data.OracleClient.OracleCommand.ExecuteDbDataReader (CommandBehavior behavior) [0x00000] in <filename unknown>:0
  at System.Data.Common.DbCommand.ExecuteReader (CommandBehavior behavior) [0x00000] in <filename unknown>:0
  at System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader (CommandBehavior behavior) [0x00000] in <filename unknown>:0
  at System.Data.Common.DbDataAdapter.Fill (System.Data.DataTable dataTable, IDbCommand command, CommandBehavior behavior) [0x00000] in <filename unknown>:0
  at System.Data.Common.DbDataAdapter.Fill (System.Data.DataTable dataTable) [0x00000] in <filename unknown>:0
  at (wrapper remoting-invoke-with-check) System.Data.Common.DbDataAdapter:Fill (System.Data.DataTable)
  at AktarmaSTOYS.OracleSideHandler.getData (System.String sql) [0x0001f] in /media/109b0d5b-fed9-4ca4-be7e-abccab4f083f/Source/AktarmaSTOYS/AktarmaSTOYS/AktarmaSTOYS/OracleSideHandler.cs:72

the code:

public static DataTable getData(string sql)
		{
			OracleConnection conn = new OracleConnection(_connectionString);

			DataTable dt = new DataTable();

			try {

				conn.Open();

				OracleDataAdapter da = new OracleDataAdapter(sql,conn);

				da.Fill(dt);

				conn.Close();

				return dt;

			} catch (Exception ex) {
				conn.Close();
				throw ex;
			}
		}