Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

CDaoQuerydef and CDaoRecordset; running a query help

Posted on 1998-08-26
2
Medium Priority
?
523 Views
Last Modified: 2013-11-19
I'm trying to do a simple search through my database.  I created a query in Access called "Simple Search".  The Criteria is: [Title] like [Search String].  Title is a field in the database.  Search String is a parameter that is set by my program.  This is my code:


//m_pDaoWorkspace and m_pDaoDatabase have already been created

CDaoQueryDef q(m_pDaoDatabase);
q.Open("Simple Search");
int isRet = q.GetReturnsRecords(); // this returns 1
int param = q.GetParameterCount(); // this returns 1
CDaoParameterInfo info;
q.GetParameterInfo(0,info);  // the 1 param = Search String

q.SetParamValue("Search String",COleVariant("*Uranium*"));
//I hope I have done this right.This might explain problem

CMyRecordset *r; // derived from CDaoRecordset
r = new CMyRecordset( m_pDaoDatabase );

if( ! r->IsOpen( ))
{
   try
   {
      r->Open(&q);
   }
   catch( CDaoException* eDaoException )
   {
      eDaoException->Delete( );
      return FALSE;
   }
}
int recs = r->GetRecordCount();

This last line is the problem.  it returns 0.


If I do not pass the CQueryDef pointer to the Open function of CMyRecordset and just open it as a normal dynset recordset GetRecordCount returns 220 as it should.  There are 220 records in the database.  So the problem lies in my CQueryDef usage and most likely, I figure how I set the parameter.  Because if I run the query in MS-Access with the same value as I set it in my program it returns some 50 records.

I'd really appreciate any information I could get about things to look at.
0
Comment
Question by:LukeSkywalker
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 2

Accepted Solution

by:
milenvk earned 800 total points
ID: 1321329
Yes the problem is where you suppose it is. DAO uses ANSI character strings, but COleVariant converts your "*Uranium*" parameter to BSTR (i.e. wide character string). Here's what you should do to fix the problem. Replace the line:

q.SetParamValue("Search String",COleVariant("*Uranium*"));

with

q.SetParamValue("Search String",COleVariant("*Uranium*", VT_BSTRT));

See VT_BSTRT is the BSTR type that uses ANSI convension. VT_BSTR is the one that's using the wide character convension and it is set by the COleVariant contrustor by default.

0
 

Author Comment

by:LukeSkywalker
ID: 1321330
You suggestion worked to solve that problem.  Thank you!
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction: Ownerdraw of the grid button.  A singleton class implentation and usage. Continuing from the fifth article about sudoku.   Open the project in visual studio. Go to the class view – CGridButton should be visible as a class.  R…
Introduction: Dialogs (2) modeless dialog and a worker thread.  Handling data shared between threads.  Recursive functions. Continuing from the tenth article about sudoku.   Last article we worked with a modal dialog to help maintain informat…
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
In this video, Percona Solutions Engineer Barrett Chambers discusses some of the basic syntax differences between MySQL and MongoDB. To learn more check out our webinar on MongoDB administration for MySQL DBA: https://www.percona.com/resources/we…
Suggested Courses

618 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question