请问为什么我用ado以text方式执行创建函数的代码执行后的函数报错

Question

错误：
Error: PLS-00103: Encountered the symbol "" when expecting one of the following:
       
          ( return compress compiled wrapped
Line: 1
Text: create or replace function func_getyesterday
代码如下
  OracleConnection con = new OracleConnection(ocsb.ConnectionString);
            con.Open();
            OracleCommand cmd = new OracleCommand();
            cmd.Connection = con;
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = this.textBox1.Text.Trim();
            try
            {
                cmd.ExecuteNonQuery();
            }
            catch (Exception ee)
            {
                MessageBox.Show(ee.Message);
            }
            con.Close();