Re: What is wrong with these SQL statements?? - C / C++ / MFC Discussion Boards

User 98858-Feb-03 7:37

8-Feb-03 7:37

I have a huge memory leak. I have found that the offending line of code is this one. I comment this part and the leak goes away. The leak is big enough for Windows to say that it is low on virtual memory on a 512 MB machine! m_hdr is a class derived from CHeaderCtrl. There is an image list associated with the header control that has 7 images. The variable direction can be only 0 or 1.

Not being particularly great at MFC UI controls, I copied this from MFC, except for the part where I derive the image index.

HDITEM curItem;<br />
m_hdr.GetItem(column, &curItem);<br />
curItem.mask= HDI_IMAGE | HDI_FORMAT;<br />
curItem.iImage = (sortindex > 3) ? 0 : ((sortindex * 2 + direction) + 1) ;<br />
curItem.fmt= HDF_LEFT | HDF_IMAGE | HDF_STRING;<br />
m_hdr.SetItem(column, &curItem);

My article on a reference-counted smart pointer that supports polymorphic objects and raw pointers

modified 29-Aug-18 21:01pm.

Re: MFC memory Leak

User 98858-Feb-03 7:49

User 9885

8-Feb-03 7:49

if the image index is always the same, then there is no leak Confused | :confused:

My article on a reference-counted smart pointer that supports polymorphic objects and raw pointers

modified 29-Aug-18 21:01pm.

Re: MFC memory Leak

Michael Dunn8-Feb-03 9:54

Michael Dunn

8-Feb-03 9:54

You need to set the mask member of the HDITEM struct before calling GetItem(), so the control knows what info you're asking for. As it is, mask is random data and who knows what the control is putting in the struct.

--Mike--
The Internet is a place where absolutely nothing happens.
-- Strong Bad

1ClickPicGrabber - Grab & organize pictures from your favorite web pages, with 1 click!
My really out-of-date homepage
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Re: MFC memory Leak

User 98858-Feb-03 10:02

User 9885

8-Feb-03 10:02

I thought it would return everything. Anyway, that settles it.
Thanks Rose | [Rose]

My article on a reference-counted smart pointer that supports polymorphic objects and raw pointers

modified 29-Aug-18 21:01pm.

RichEdit question !

Hadi Rezaee8-Feb-03 7:34

Hadi Rezaee

8-Feb-03 7:34

Hello,

I've to add large strings with very different styles to richedit.
how can i add them all to rich edit and then show all in a second ??!

Because it makes filickers when i add each string to richedit !

Regards,

My month article: Game programming by DirectX by Lan Mader.
Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

How to get an added class to shwo up in class wizard

nss8-Feb-03 2:29

nss

8-Feb-03 2:29

In my old project I added a class CsortListCtrl derived from CListCtrl, and when I #included it (I think thats all I did) when I put a listctrl on the dialog and used the CW to make a variable for it, it gave me two choices for the type of the control: SO I could either make it CListCTrl or CSortListCtrl. In this new project I've put the control on the form, #included it, but the CW is only offering me one choice i.e. it can only be of type CListCtrl. WHat to do? I need

CSortLIstCTrl mySortCTrl;

What is wrong with these SQL statements??

IrishSonic8-Feb-03 0:26

IrishSonic

8-Feb-03 0:26

Hiya getting a message saying "Database error - There were no columns specified to retrive." when using these 2 lines:

SqlString = "DELETE * from Branches WHERE Branch_No LIKE '4%' ";

OR

SqlString = "INSERT INTO Branches (Branch_No,Branch_Name) VALUES ('6','Derry') ";

But Branch_No is the first column and Branch_Name is the second..

Am I using the statements wrong??

Thanks,
grahamoj.

Re: What is wrong with these SQL statements??

vin8-Feb-03 1:08

vin

8-Feb-03 1:08

grahamoj wrote:
SqlString = "DELETE * from Branches WHERE Branch_No LIKE '4%' ";

It should be DELETE FROM <table_name> WHERE <condition>

Vini

Re: What is wrong with these SQL statements??

Ted Ferenc8-Feb-03 4:42

Ted Ferenc

8-Feb-03 4:42

grahamoj wrote:
SqlString = "INSERT INTO Branches (Branch_No,Branch_Name) VALUES ('6','Derry') ";

1. What is the error message
2. Does the row exists, if so the statement will fail
3. Is Branch_No declared as INT it so try 6 not '6', although I don't think this will make any diference.

If I have seen further it is by standing on the shoulders of Giants. - Isaac Newton 1676

Here is my code...

IrishSonic8-Feb-03 7:35

IrishSonic

8-Feb-03 7:35

// Open the database
database.Open(NULL,false,false,sDsn);

// Allocate the recordset
CRecordset recset( &database );

// Build the SQL statement
SqlString = "DELETE FROM Branches WHERE Branch_No LIKE '4%'";

//SqlString = "INSERT INTO Branches (Branch_No,Branch_Name) VALUES ('6','Derry') ";

// Execute the query
recset.Open( CRecordset::forwardOnly,SqlString,CRecordset::readOnly );

I now know it is the last line, so changed it to:

recset.Open( AFX_DB_USE_DEFAULT_TYPE,SqlString,CRecordset::none );

but this still does not delete the line. The error message I am getting is:

"Database Error: Attempt to open a table failed - there were no columns to retrive were specified".

But my table is called Branches and is specified!!

Any ideas.

grahamoj

Re: Here is my code...

Ted Ferenc8-Feb-03 10:09

Ted Ferenc

8-Feb-03 10:09

What I always do is use "Query Analyzer" to check out my SQL statement, I tried the following on a scratch table

use teds<br />
INSERT INTO winrasdialit (col001, col002, col003) VALUES('hello', getdate(), 5)

It works OK, so if your SQL statement works in "Query Analyzer" you have at least eliminated one possible error. It does look like you do not have the database open for read only as delete seems to work?

I don't use CRecordset so I can't comment on your synatx

If I have seen further it is by standing on the shoulders of Giants. - Isaac Newton 1676

Re: Here is my code...

Kelly Herald9-Feb-03 18:02

Kelly Herald

9-Feb-03 18:02

Since the DELETE and INSERT commands don't return a recordset you shouldn't use the CDaoRecordset (or CRecordset) class to execute them. Just use the Execute method in the CDaoDatabase (or CDatabase) class.

Kelly Herald
Software Developer
MPC formerly Micronpc

Re: What is wrong with these SQL statements??

JockeP9-Feb-03 6:08

JockeP

9-Feb-03 6:08

Hi! I'm just curious how you manage to execute those insert and delete queries? I get rt error when doing it like this:

CDaoDatabase* m_pDB;
CDaoRecordset* m_pRS;
m_pDB = new CDaoDatabase;
m_pRS = new CDaoRecordset(m_pDB);

try {
m_pDB->Open("c:\\accessdb\\db1.mdb");
// CString strQuery = _T("SELECT * FROM Table1"); //Works just fine...
CString strQuery = _T("INSERT INTO Table1 VALUES ('3', 'Olga')"); //Doesn't work
m_pRS->Open(dbOpenDynaset, strQuery);
} catch (CDaoException* e) {
AfxMessageBox(e->m_pErrorInfo->m_strDescription);
e->Delete();
}

Can you tell me how to do it?

CAsyncSocket problem

Kazz7-Feb-03 23:08

Kazz

7-Feb-03 23:08

Hi, I just started getting into C++/MFC and I've hit my first snag. I'm making a simple program that downloads the contents of a webpage and then sorts out href's. The problem comes into play in the OnReceive event handler. I'm getting 'The instruction at 0x77f475cc referenced by 0x0000000. The memory could not be "written"' right after I get the first packet. I suppose I'm doing something wrong with a pointer? Null maybe? It ONLY does this when I compile for release, it works perfectly when I compile for debug. After changing around some compiler options (turning off optimizations) it still does the same thing. I've done step by step debugging and the last thing I'm seeing is 'Receiving HTML'. I've looked over it for a long time and even showed it to a few friends, they couldn't figure it out either. My guess is it's the pBuf pointer but I don't see why, if anybody could give me some tips I would appreciate it! Here's my code..

void CReconDlg::OnReceive()<br />
{<br />
	char *pBuf = new char[1024];<br />
	CString strRecvd, strConlen = "Content-Length:", actualLen;<br />
	char *pConlen;<br />
        int wholePacket, int result, int lenLen, int endPos, int iBufSize = 1024, int iRcvd, int packetStart;<br />
<br />
        // get the data<br />
	iRcvd = m_sConSocket.Receive(pBuf, iBufSize);<br />
        // strip any garbage off of the buffer<br />
	pBuf[iRcvd] = NULL;<br />
<br />
	// error trap<br />
	if (iRcvd == SOCKET_ERROR){<br />
		MessageBox("Error on receiving socket");<br />
	}else{<br />
                // debug step and append buffer to CString for manipulation<br />
		m_sStat = "Receiving HTML..";<br />
		strRecvd += pBuf;<br />
	}<br />
	<br />
        // search for the Content-Length so we know just how much data we're getting<br />
	pConlen = strstr(strRecvd, strConlen);<br />
	<br />
        // if it's found parse out the Content-Length: header feild and append everything AFTER the header to a new string<br />
	if (pConlen != NULL){<br />
		result = (int)(pConlen - strRecvd + 1) + 15;<br />
		endPos = strRecvd.Find("\n", result) - 1;<br />
		lenLen = (endPos - result);<br />
		actualLen = strRecvd.Left(endPos);<br />
		realLen = actualLen.Right(lenLen);<br />
		packetStart = strRecvd.Find("\r\n\r\n", result);<br />
		int packetLen1 = (strlen(strRecvd) - packetStart);<br />
		m_strIn += strRecvd.Right(packetLen1);<br />
	}else{<br />
                // if there's no header just throw the entire string onto our 'raw packet'<br />
		m_strIn += strRecvd;<br />
	}<br />
                // get lengths<br />
		wholePacket = strlen(m_strIn) - 4;<br />
		CString display ;<br />
		display.Format("%d", wholePacket);<br />
		<br />
        // have we got all of it? if so continue to parse..<br />
	if (realLen == display){<br />
		m_sStat = "Received entire packet, parsing..";<br />
		ParseString(m_strIn);<br />
		m_sConSocket.Close();<br />
		m_strIn = "";<br />
		realLen = "";<br />
		<br />
	}<br />
	<br />
	UpdateData(FALSE);<br />
<br />
}

Re: CAsyncSocket problem

Michael Dunn8-Feb-03 7:32

Michael Dunn

8-Feb-03 7:32

First thing I noticed is that this:

pBuf[iRcvd] = NULL;

is a buffer overrun. What happens if iRcvd is 1024? You write a 0 to one byte past the end of the array, overwriting whatever is on the stack at that point.

--Mike--
The Internet is a place where absolutely nothing happens.
-- Strong Bad

1ClickPicGrabber - Grab & organize pictures from your favorite web pages, with 1 click!
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

help: odbc error:field data truncated during data fetch

trustno17-Feb-03 21:23

trustno1

7-Feb-03 21:23

hi,

when i attempt to use odbc to retrieve data from ms access database, i get an error "error: field data truncated during data fetch" right after executing odbc's Open().. odbc crashed at retrieve data from a field, datatype: memo.. i did a couple test and found out if the field contain more than 255 characters the my program crashes.. is there anyway to fix the problem? thanx in advance..

vc sdk

Ashwin C7-Feb-03 21:10

Ashwin C

7-Feb-03 21:10

which the best book to learn vc SDK?
ive heard of petzold as one.

-We are born naked, wet and hungry. Then things get worse.

Re: vc sdk

Philip Patrick7-Feb-03 21:53

Philip Patrick

7-Feb-03 21:53

You mean Windows API? Well, Petzold is still the best IMHO Smile | :)

Philip Patrick
Web-site: www.stpworks.com
"Two beer or not two beer?" Shakesbeer

how to get size of any control

TSrinivasR7-Feb-03 20:44

TSrinivasR

7-Feb-03 20:44

i need to find out the size of the
Tab control....
"how to get size of any control"

Very Urgent-Downloading files from internet

vcarivu7-Feb-03 20:41

vcarivu

7-Feb-03 20:41

Hi all

I have to download that files(from internet sites,DLL or exe anything)to store in some temporary area like C:Pgmfiles\temp
To do that how to write coding in VC++?

Thanks for viewing this.Please help me.

Re: Very Urgent-Downloading files from internet

Ted Ferenc7-Feb-03 21:47

Ted Ferenc

7-Feb-03 21:47

Look at the MSDN example:-

TEAR: "Tearing" HTML Pages Off the Internet

If I have seen further it is by standing on the shoulders of Giants. - Isaac Newton 1676

Re: Very Urgent-Downloading files from internet

Michael Dunn8-Feb-03 7:33

Michael Dunn

8-Feb-03 7:33

Check out Using Internet Explorer to download files for you[^]

--Mike--
The Internet is a place where absolutely nothing happens.
-- Strong Bad

1ClickPicGrabber - Grab & organize pictures from your favorite web pages, with 1 click!
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

Kill Process

suresh_sathya7-Feb-03 20:22

suresh_sathya

7-Feb-03 20:22

iam running notepad called notepad.exe
what api i should use to kill the process ex.notepad.exe
i just pass exe name.It should kill the process

Re: Kill Process

includeh108-Feb-03 1:31

includeh10

8-Feb-03 1:31

use CreateProcess() to run the exe, then call TerminateProcess(handle).

handle is inside one of params of CreateProcess().

includeh10

Exe optimization

suresh_sathya7-Feb-03 20:22

suresh_sathya

7-Feb-03 20:22

I wrote a small console application in vc++.I just print hello world.But the exe size in release mode comes around 36 KB.How to reduce the memory size.I want to reduce to 10 KB.What are the things i can remove to reduce the exe size.

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.