系统年份 YYYY 加上 coulmn 的值 MMDD 在 C# 中作为“dd-MMM-yyyy”插入到数据库中

Question

I am to read text file where a column of purchase date with format MMDD is available. It is being read and inserted all records successfully. But now i want to insert "system year" with "purchase date" as "dd-MMM-yyyy" into date column of database. Example: If purchase date is "0812" and System Year is '19', then date will be "12-AUG-19". How can i do this ?

Answer 1

As of Oracle, you'd apply a few transformations :

• concatenate value you have (0812) with this year (which is what extract does)
• apply to_date to it, with appropriate format mask ( mmddyyyy )
• apply to_char to that value, with desired/final format mask ( dd-mon-yyyy )

Something like this:

SQL> select to_char(to_date('0812' || extract(year from sysdate), 'mmddyyyy'), 'dd-mon-yyyy') result from dual;
                             ----
                             this is what you have, MMDD

RESULT
-----------
12-aug-2019

SQL>

Answer 2

If you are looking for C# code then, you can first Parse , then create a required DateTime and, finally, format the DateTime :

  string source = @"0812";
  int SystemYear = 19;

  // Parsed date, note, that year is DateTime.Now.Year, not required SystemYear
  DateTime date = DateTime.ParseExact(source, "MMdd", CultureInfo.InvariantCulture);

  date = new DateTime(
    CultureInfo.InvariantCulture.Calendar.ToFourDigitYear(SystemYear), // SystemYear
    date.Month,                                                        // same Month
    date.Day);                                                         // same Day

  // "12-AUG-19"
  string result = date.ToString("dd'-'MMM'-'yy", CultureInfo.InvariantCulture).ToUpper();

Answer 3

It depends what is data format in your tables column. If it's type of Date, then showing 12-AUG-19 is just a display issue, and has nothing to do with inserting. If it's varchar column, then you first need to read your date from source fe:

var source = "0812";
source += DateTime.Now.Year;
Console.WriteLine(source);
var date = DateTime.ParseExact(source, "MMddyyyy", System.Globalization.CultureInfo.InvariantCulture);
Console.WriteLine(date);

So now you have date as DateTime object, and it depends on your DB structure if you will post it as string to DB, or as proper Date column.

Answer 4

In Oracle you can insert a date using many different formats, so it would not be necessary to have the format 'DD-mon-YY' to insert the value in a date column. The TO_DATE function uses the current year value by default to complete the format:

SQL> SELECT TO_DATE('0812', 'MMDD')from dual;

TO_DATE('0812','M
-----------------
12/08/19 00:00:00

And this is an example of what I mean:

SQL> CREATE TABLE DATE_SAMPLE ( DATE_VALUE DATE);

Table DATE_SAMPLE creado.

SQL> INSERT INTO DATE_SAMPLE SELECT TO_DATE('0812', 'MMDD')from dual;
1 fila insertadas.

SQL> SELECT TO_CHAR(DATE_VALUE, 'DD-mon-YY') from DATE_SAMPLE;

TO_CHAR(DATE_VALUE,'DD-MON-YY')                                            
---------------------------------------------------------------------------
12-ago-19

You can insert a date specifying the format in the TO_DATE function and read it in the desired format using the TO_CHAR function.

TO_DATE

TO_CHAR