如何从OracleParameter对象获取值

Question

如下面所示的代码,我想从OracleParameter对象中获取值.它的数据类型是datetime.

...

Dim cmd As New OracleCommand("stored_proc_name", cnObject)
cmd.Parameters.Add("tran_date_out", OracleDbType.Date, ParameterDirection.Output)

...

cmd.ExecuteNonQuery()

...

Dim tranDate As Date
tranDate = cmd.Parameters("tran_date_out").Value

当我为tranDate变量赋值时,我收到一个错误.但如果我编码如下,我只得到日期.

tranDate = CDate(cmd.Parameters("tran_date_out").Value.ToString)

那么如何才能获得tranDate变量的日期和时间值？

Answer 1

脱离我的头脑,当一个out参数被分配给一个奇怪的Oracle盒装类型时,OracleParameter.Value.它似乎是一个完全糟糕的设计或Oracle的一部分......但不是返回String,而是获得OracleString等.

每个Oracle类型都有一个.value的具有系统类型,当然他们不都实现一个共同的接口暴露这一点,所以我所做的就是基本上写一个方法拆箱的类型:

/// <summary>
/// The need for this method is highly annoying.
/// When Oracle sets its output parameters, the OracleParameter.Value property
/// is set to an internal Oracle type, not its equivelant System type.
/// For example, strings are returned as OracleString, DBNull is returned
/// as OracleNull, blobs are returned as OracleBinary, etc...
/// So these Oracle types need unboxed back to their normal system types.
/// </summary>
/// <param name="oracleType">Oracle type to unbox.</param>
/// <returns></returns>
internal static object UnBoxOracleType(object oracleType)
{
  if (oracleType == null)
    return null;

  Type T = oracleType.GetType();
  if (T == typeof(OracleString))
  {
    if (((OracleString)oracleType).IsNull)
      return null;
    return ((OracleString)oracleType).Value;
  }
  else if (T == typeof(OracleDecimal))
  {
    if (((OracleDecimal)oracleType).IsNull)
      return null;
    return ((OracleDecimal)oracleType).Value;
  }
  else if (T == typeof(OracleBinary))
  {
    if (((OracleBinary)oracleType).IsNull)
      return null;
    return ((OracleBinary)oracleType).Value;
  }
  else if (T == typeof(OracleBlob))
  {
    if (((OracleBlob)oracleType).IsNull)
      return null;
    return ((OracleBlob)oracleType).Value;
  }
  else if (T == typeof(OracleDate))
  {
    if (((OracleDate)oracleType).IsNull)
      return null;
    return ((OracleDate)oracleType).Value;
  }
  else if (T == typeof(OracleTimeStamp))
  {
    if (((OracleTimeStamp)oracleType).IsNull)
      return null;
    return ((OracleTimeStamp)oracleType).Value;
  }
  else // not sure how to handle these.
    return oracleType;
}

这可能不是最干净的解决方案,但...这是快速和肮脏的,一个第二确实为我工作.

只需将OracleParameter.Value传递给此方法即可.

实际上,在回答之前,我可能只有1/2读过您的问题.我认为Oracle的Date类型只包含日期而不是时间.

oracle类型Timestamp既有日期又有时间.

希望有所帮助!:)