MFC - CRecordSet - MySQL - BLOB

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Hi

I have a simple task to transfer data from multiple tables in a MySql database into a single table.

I am using MFC for the task (simply because I haven't programmed in C# or C++ for about 5 years :( )

I need to jog my memory on Variable and strings etc so could someone help me with the following question.

I am using CRecordSet -> GetFieldValue(). Now this is fine for my text fields etc, but when it comes to a BLOB, or MEDIUMTEXT I'm struggling with an error.

MIDL

CString sProdName;
sections.Open(CRecordset::snapshot,SqlString);
sections.GetFieldValue(_T("Section text"),sProdName);

Should I be creating another type of variable to read this information in ? I don't need to do anything with it apart from write it straight back out.

Thanks.
Austin.

Posted 15-Jun-11 3:10am

Member 3294750

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2 solutions

Solution 1

you need to read the data with the correct function/flags. Cant you find a sample?

Posted 21-Jun-11 4:04am

KarstenK

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Member 3294750 · Accepted Answer · 2011-06-21T04:43:00

Thanks for the reply.

Worked out the solution myself, doesn't seem to be any clear samples about.

CDBVariant sVariant;
CString sProdName;
sections.Open(CRecordset::snapshot,SqlString);
sections.GetFieldValue(_T("Section text"),sVariant);
if (sVariant.dwtype == DBVT_ASTRING)
    sProdName=(CString)*sVariant.m_pstringA;

Not the greatest solution either, due to the age and lack of support for C++ MFC nowadays, I moved to C#

 char []desc=null;
 char []test=null;
long len = 
DbReader.GetChars(count, 0, test, 0, 65536);     //I know this field will not contain more than 65536 chars, so get the actual length;
DbReader.GetChars(count, 0, desc, 0, (int)len); // now I know the length, get it as chars
thedesc = new String(desc, 0, (int)len); // put it into a new String class from position 0 to len

Hope this helps someone out :)