使用c＃执行oracle存储过程抛出错误ORA-06502：PL / SQL：数字或值错误\ nORA-06512

Question

我在oracle中使用以下存储过程

PROCEDURE proc_test (
    product_id                  IN Product_map.product_id%type,
    external_product_id                   IN Product_map.ex_product_id%type,
    product_seller               OUT VARCHAR2,
    product_name                 OUT VARCHAR2
) IS
BEGIN
     SELECT  seller, product_name
     INTO    product_seller, name
     FROM    product_map
     WHERE   product_id = product_id
     AND     ex_product_id = external_product_id;

END;

数据类型

product_id        VARCHAR2(300 BYTE)
ex_product_id     VARCHAR2(30 BYTE)
product_seller    VARCHAR2(10 BYTE)
product_name      VARCHAR2(400 BYTE)

执行存储过程和返回值的C＃代码

using (OracleConnection objConn = new OracleConnection("Data Source=ORCL; User ID=scott; Password=tiger"))
{
    OracleCommand objCmd = new OracleCommand();
    objCmd.Connection = objConn;
    objCmd.CommandText = "proc_test";
    objCmd.CommandType = CommandType.StoredProcedure;
    cmdBuilder.Parameters.Add("product_id", OracleDbType.Varchar2).Value = "a123";
    cmdBuilder.Parameters.Add("external_product_id", OracleDbType.Varchar2).Value = "xyz123";
    cmdBuilder.Parameters.Add("product_seller", OracleDbType.Varchar2).Direction = ParameterDirection.Output;
    cmdBuilder.Parameters.Add("product_name", OracleDbType.Varchar2).Direction = ParameterDirection.Output;
    try
    {
        objConn.Open();
        objCmd.ExecuteNonQuery();
        System.Console.WriteLine($"Product name is is {objCmd.Parameters["product_name"].Value}");  
    }
    catch (Exception ex)
    {
       System.Console.WriteLine("Exception: {0}",ex.ToString());
    }
    objConn.Close();
}

我收到以下错误 -

  

ORA-06502：PL / SQL：数字或值错误\ nORA-06512。