在PL/SQL中执行sql语句是提示：ORA-01008: 并非所有变量都已绑定
该怎么解决，如何绑定那些变量？
using (CoreLab.Oracle.OracleConnection objConn = new CoreLab.Oracle.OracleConnection(ConfigurationManager.AppSettings["connectionString"]))
{
CoreLab.Oracle.OracleTransaction trans = null;
try
{
objConn.Open()
trans = objConn.BeginTransaction();
string sql = "select DataID from system.SSJ_Data where ServerName=:ServerName and FileName=:FileName";
CoreLab.Oracle.OracleCommand objCmd = objConn.CreateCommand();
objCmd.Transaction = trans;
objCmd.CommandText = sql;
objCmd.CommandType = CommandType.Text;
objCmd.Parameters.Add(":ServerName", ServerName);
objCmd.Parameters.Add(":FileName", Path.GetFileName(p));
//CoreLab.Oracle.OracleDataReader objDR = objCmd.ExecuteReader();
int dataID = int.MinValue;
object objResult = null;
objResult = objCmd.ExecuteScalar();
if (objResult != DBNull.Value && objResult != null)
{
dataID = int.Parse(objResult.ToString()); }
objCmd.Parameters.Clear();
bool isInserted = false;
if (dataID == int.MinValue)