SQL Bulkcopy YYYYMMDD问题 [英] SQL Bulkcopy YYYYMMDD problem

问题描述

我在asp.net 3.5使用SQL Bulkcopy一个字符串到日期的转换问题，C＃

I have a String to Date conversion problem using SQL Bulkcopy in asp.net 3.5 with C#

我看了一个大的CSV文件（的 CSV读者）。一个读应该被加载到SQL Server 2008中日期列中的字符串。

I read a large CSV file (with CSV reader). One of the strings read should be loaded into a SQL server 2008 Date column.

如果文本文件，例如包含字符串'2010-12-31'，SQL Bulkcopy负荷。它没有任何问题到日期列

If the textfile contains for example the string '2010-12-31', SQL Bulkcopy loads it without any problems into the Date column.

不过，如果字符串为20101231，我得到一个错误：结果
的从数据源String类型的给定值不能转换为键入指定的目标列日

However, if the string is '20101231', I get an error:
The given value of type String from the data source cannot be converted to type date of the specified target column

该文件含有80万条记录，所以我不能创建数据表....

The file contains 80 million records so I cannot create a datatable....

SqlBulkCopy的Columnmappings等方面都ok了。也改变为DateTime于事无补。

SqlBulkcopy Columnmappings etc. are all ok. Also changing to DateTime does not help.

我试过

SET DATEFORMAT ymd;

但是，这并不能帮助。

But that does not help.

任何想法如何告诉SQL Server接受这种格式？否则，我将创建CSV读者自定义修复，但我宁愿在SQL的东西。

Any ideas how to tell SQL Server to accept this format? Otherwise I will create a custom fix in CSV reader but I would prefer something in SQL.

更新
上的两个跟进答案，我使用这样的SQL bulkcopy（在另一个问题提出＃2）：

update Following up on the two answers, I am using SQL bulkcopy like this (as proposed on Stackoverflow in another question):

CSV阅读（见上在CodeProject上的链接）返回字符串值（不强类型）。该CSVreader实现System.Data.IDataReader，所以我可以做这样的事情：

The CSV reader (see the link above on codeproject) returns string values (not strong typed). The CSVreader implements System.Data.IDataReader so I can do something like this:

using (CsvReader reader = new CsvReader(path)) 
using (SqlBulkCopy bcp = new SqlBulkCopy(CONNECTION_STRING))
{ bcp.DestinationTableName = "SomeTable"; 
  // columnmappings
  bcp.WriteToServer(reader); } 

从IDataReader的来的所有字段都是字符串，所以，除非我改变，我不能使用C＃方法在CSVreader颇有几分

All the fields coming from the iDataReader are strings, so I cannot use the c# approach unless I change quite a bit in the CSVreader

我的问题，因此没有就如何解决它在C＃中的关系，我能做到这一点，但我想，以防止这一点。

My question is therefore not related on how to fix it in C#, I can do that but i want to prevent that.

这是奇怪的，因为如果你在SQL像

It is strange, because if you do a in sql something like

 update set [somedatefield] = '20101231' 

它也可以，只是不能与bulkcopy。

it also works, just not with bulkcopy.

任何想法，为什么？

谢谢，
Pleun

Thanks for any advice, Pleun

推荐答案

如果你可以在C＃本身韩德尔它那么这段代码将有助于让字符串作为一个DateTime对象中，你可以通过直接

If you can handel it in C# itself then this code will help get the date in the string as a DateTime object which you can pass directly

//datestring is the string read from CSV
DateTime thedate = DateTime.ParseExact(dateString, "yyyyMMdd", null);

如果你想让它格式化为字符串，然后：

If you want it to be formatted as string then:

string thedate = DateTime.ParseExact(dateString, "yyyyMMdd", null).ToString("yyyy-MM-dd");

祝你好运。

Good luck.

更新

在您的情况我不知道为什么日期不自动格式化，但是从C＃，你需要获得和传递的过程中干扰数据到在WriteToServer（）方法。最好的，我认为你可以做（​​牢记性能）是拥有的DataRow的项目缓存，并将其传递给的在WriteToServer（）方法。我只是写的代码示例在一分钟...

In your scenario i don't know why date is not automatically formatted but from C# you need to get in and Interfere in the process of passing the data to the WriteToServer() method. Best i think you can do (keeping in mind the Performance) is to have a cache of DataRow items and Pass them to the WriteToServer() method. I will just write the sample code in a minute...

//A sample code.. polish it before implementation
//A counter to track num of records read
long records_read = 0;
While(reader.Read())
{
    //We will take rows in a Buffer of 50 records
    int i = records_read;//initialize it with the num of records last read
    DataRow[] buffered_rows = new DataRow[50];
    for(;i<50 ;i++)
    {
        //Code to initialize each rows with the data in the reader
        //.....
        //Fill the column data with Date properly formatted
        records_read++;
        reader.Read();
    }
    bcp.WriteToServer(buffered_rows);
}

它不是完整的代码，但我认为你可以解决它...

Its not full code but i think you can work it out...

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