SQL Server导入向导失败难懂的讯息(SQL Server Import wizard fai

我只是想导入从平面文件的两列到新表。我已经设置的一列，“代码”，是varchar(50)和另一列，“说明”，是nvarchar(max) 。

导入失败与以下消息：

- Executing (Error)
Messages
Error 0xc02020a1: Data Flow Task 1: Data conversion failed. The data conversion for column "Description" returned status value 4 and status text "Text was truncated or one or more characters had no match in the target code page.".
 (SQL Server Import and Export Wizard)

Error 0xc020902a: Data Flow Task 1: The "output column "Description" (14)" failed because truncation occurred, and the truncation row disposition on "output column "Description" (14)" specifies failure on truncation. A truncation error occurred on the specified object of the specified component.
 (SQL Server Import and Export Wizard)

Error 0xc0202092: Data Flow Task 1: An error occurred while processing file "C:\Users\rinaldo.tempo\Desktop\ICD10_Edition4_CodesAndTitlesAndMetadata_GB_20120401.txt" on data row 3.
 (SQL Server Import and Export Wizard)

Error 0xc0047038: Data Flow Task 1: SSIS Error Code DTS_E_PRIMEOUTPUTFAILED.  The PrimeOutput method on component "Source - ICD10_Edition4_CodesAndTitlesAndMetadata_GB_20120401_txt" (1) returned error code 0xC0202092.  The component returned a failure code when the pipeline engine called PrimeOutput(). The meaning of the failure code is defined by the component, but the error is fatal and the pipeline stopped executing.  There may be error messages posted before this with more information about the failure.
 (SQL Server Import and Export Wizard)

该错误信息显示给我，因为它是被放置在“说明”一栏，这是类型的数据是越来越截断nvarchar(max) ！已经直勾勾地输入数据，我想说的描述是从来没有超过约2或300个字符，所以这是不可能的。

任何人都可以提出这里有什么问题？