Unable to parse Oracle timestamp in C#

Question

I have timestamp of Oracle:

string timestamp = "23-JUN-14 09.39.04.000000000 AM";

I am not able to parse it into system date time object. I used:

CultureInfo provider = CultureInfo.InvariantCulture;
                String format = "yy-MMM-dd hh:mm:ss:fffffff";
                string timestamp = "10-DEC-07 10.32.47.797201123 AM";
                {
                    var date = DateTime.ParseExact(timestamp, format, provider);
                    DateTime dateTime = DateTime.ParseExact(timestamp.ToString(), "dd-MMM-y HH:mm:ss", CultureInfo.InvariantCulture);
}

It is still passing error. It is working 7 f after m but not more than that. I used try Parse, try ParseExact - is there any way?

Answer 1

According to https://stackoverflow.com/a/23198962/328864, there is no way to skip parts of an exact pattern, so i guess you could do something like this:

CultureInfo provider = CultureInfo.InvariantCulture;
string timestamp = "10-DEC-07 10.32.47.797201123 AM";
String format = String.Format("yy-MMM-dd hh.mm.ss.fffffff{0} tt", timestamp.Substring(26,2));

DateTime date = DateTime.ParseExact(timestamp, format, provider);
Console.WriteLine(date);

Not very pretty though.

Answer 2

.NET DateTime structure has a precision of tick - 100 nanoseconds - 0.0000001 of second - 7 decimal positions after the point.

Oracle TimeStamp has a precision of up to nanosecond - 0.000000001 - 9 decimal positions after the point.

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That is why standard DateTime cannot store all possible oracle TimeStamps. And its parsing function simply fail on more precise string representations of TimeStamp.

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So, what could be tried:

• Format your TimeStamps in query to some format parseable by DataTime(with loss of precision if necessary) - http://docs.oracle.com/cd/B19306_01/server.102/b14200/sql_elements004.htm
• Or create your own more precise CustomTimeStamp .Net structure and parse to it manually

Answer 3

Once we started to use ODP.NET, we had to implement an extension like below:

public static T ConvertOracleValue<T>(this object value)
{
     if (value != null)
     {
          Type typeOfValue = value.GetType();

          if (typeOfValue.Namespace.Contains("Oracle.DataAccess"))
          {
              if (typeOfValue.Name.Equals("OracleTimeStamp"))
              {
                   int tempInt = 0;
                   Oracle.DataAccess.Types.OracleTimeStamp ots = (Oracle.DataAccess.Types.OracleTimeStamp)value;
                   tempInt = Int32.TryParse(ots.Millisecond.ToString("000").Substring(0, 3), out tempInt) ? tempInt : 0;
                   DateTime ret = new DateTime(ots.Year, ots.Month, ots.Day, ots.Hour, ots.Minute, ots.Second, tempInt);
                    return ConvertHelper.ConvertValue<T>(ret);
              }
              if (typeOfValue.Name.Equals("OracleTimeStampLTZ"))
              {
                    int tempInt = 0;
                    Oracle.DataAccess.Types.OracleTimeStampLTZ ots = (Oracle.DataAccess.Types.OracleTimeStampLTZ)value;
                    tempInt = Int32.TryParse(ots.Millisecond.ToString("000").Substring(0, 3), out tempInt) ? tempInt : 0;
                    DateTime ret = new DateTime(ots.Year, ots.Month, ots.Day, ots.Hour, ots.Minute, ots.Second, tempInt);
                    return ConvertHelper.ConvertValue<T>(ret);
              }
              if (typeOfValue.Name.Equals("OracleTimeStampTZ"))
              {
                    int tempInt = 0;
                    Oracle.DataAccess.Types.OracleTimeStampTZ ots = (Oracle.DataAccess.Types.OracleTimeStampTZ)value;
                    tempInt = Int32.TryParse(ots.Millisecond.ToString("000").Substring(0, 3), out tempInt) ? tempInt : 0;
                    DateTime ret = new DateTime(ots.Year, ots.Month, ots.Day, ots.Hour, ots.Minute, ots.Second, tempInt);
                    return ConvertHelper.ConvertValue<T>(ret);
              }

              string temp = value.ToString();
              return ConvertHelper.ConvertValue<T>(temp);
          }
      }
      else
      {
           return default(T);
      }

      return ConvertHelper.ConvertValue<T>(value);
}

where ConvertHelper.ConvertValue is another extension:

public static class ConvertHelper
    {
        public static T ConvertValue<T>(object value)
        {
            Type typeOfT = typeof(T);
            if (typeOfT.BaseType != null && typeOfT.BaseType.ToString() == "System.Enum")
            {
                return (T)Enum.Parse(typeOfT, Convert.ToString(value));
            }
            if ((value == null || value == Convert.DBNull) && (typeOfT.IsValueType))
            {
                return default(T);
            }
            if (value is IConvertible)
            {
                return (T)Convert.ChangeType(value, typeOfT, new CultureInfo("en-GB"));
            }

            return (T)Convert.ChangeType(value, typeOfT);
        }
}

This worked like a charm in our test, integration and production environments.