如何从sqlserver检索PDF二进制数据 [英] How to retrive PDF Binary data from sqlserver

问题描述

亲爱的所有人，

如何使用VC ++从sqlserver检索PDF二进制数据并将其保存到PDF文件?

我们的代码是:

Dear All,

How to retrive PDF Binary data from sqlserver and save to PDF file using VC++ ?

our code is:

qry="select document from  emptable where empno=1"; //document is image datatype
crs->Open(CRecordset::snapshot,qry,CRecordset::readOnly|CRecordset::executeDirect);

                 while(!crs->IsEOF())
		    {
			crs->GetFieldValue("document",strDocument);
						
		     }

我们已经使用CString检索了二进制数据，但是当我们将这些数据写入PDF文件时，它将无法正常工作.

我们认为问题是CString，所以如果没有CString，我们该怎么办.
请给我们您的建议.

谢谢
raju.

we have retrive binary data using CString but when we write this data into a PDF file it is NOT working.

we think the problem is CString So without CString how can we do.
Please give to us your suggestions.

Thank you,
raju.

推荐答案

以与存储数据相同的方式读取数据.数据通常以VARIANT(或COleVariant)的形式提供.对于二进制数据(dbBinary和dbLongBinary)，变量类型为VT_ARRAY | VT_UI1.

将非变量类型传递给GetFieldValue()时，如果可能，数据将转换为目标类型.

Read the data in the same way as they are stored. Data are usually provided as VARIANT (or COleVariant). With binary data (dbBinary and dbLongBinary) the variant type is VT_ARRAY | VT_UI1.

When passing non-variant types to GetFieldValue(), data are converted to the destination type if possible.

您已经获得了答案(实际上有1个以上)

You have already been given the answer (more than 1 in fact) here[^]. Do not convert file contents to CStrings unless you know that the data is pure text. And even if you do know that, it is not a sensible idea. Spend some time studying file handling in computers and how to manage binary data.

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