DOCUMENT:Q325765  09-AUG-2002  [odbc]
TITLE   :"String Data, Length Mismatch" Err Msg w/ ODBC Driver for SQL
PRODUCT :Open Database Connectivity (ODBC)
PROD/VER::2.5,2.6,2.7,2000.80.194,2000.80.380,2000.81.7713.0,3.7
OPER/SYS:
KEYWORDS:

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft ODBC Driver for SQL Server, version 3.7 
 - Microsoft ODBC Driver for SQL Server 2000, versions 2000.80.194, 2000.80.380, 2000.81.7713.0 
 - Microsoft Data Access Components versions 2.5, 2.6, 2.7 
-------------------------------------------------------------------------------

SYMPTOMS
========

If an application inserts more than 400 kilobytes (KB) of data in SQL Server by
using ODBC, you may receive the following error message:

   DIAG [22026] [Microsoft][ODBC SQL Server Driver]String data, length mismatch
   (0)

You receive this error message if the application uses the ODBC application
programming interface (API) directly (that is, the SQLBindParameter, the
SQLParamData, the SQLExecute, and the SQLPutData APIs). Additionally, you
receive this error message if you try to insert data through a Microsoft Access
linked table to SQL Server, and if all of the following conditions are true:

 - The application inserts more than 400 KB of data.

 - The application calls SQLBindParameter with SQL_C_WCHAR and SQL_LONGVARCHAR.
   If the application links with Access, Access calls SQLBindParameter with
   SQL_C_WCHAR and SQL_LONGVARCHAR.

 - The server data type is non-Unicode such as "text." Internally, this causes
   the SQL Server driver to convert the data that you have passed from Unicode
   to MultiByte.

 - The application uses the SQL_LEN_DATA_AT_EXEC(409602) macro to indicate that
   you are trying to send more than 400 kilobytes of data. If you are using
   Access, Access uses this macro automatically.

This problem occurs with the ODBC Driver for SQL Server that is included with
Microsoft Data Access Components (MDAC) versions 2.5, 2.6, and 2.7.

CAUSE
=====

Based on the ODBC specification, when a client calls SQL_LEN_DATA_AT_EXEC and
passes a number as its parameter, such as SQL_LEN_DATA_AT_EXEC(409602), the
number that is passed indicates how many bytes of data is sent when the client
calls SQLPutData later. This problem occurs because the ODBC Driver for SQL
Server incorrectly interprets this number as the number of characters that are
passed instead of number of bytes that are passed.

RESOLUTION
==========

A supported fix is now available from Microsoft, but it is only intended to
correct the problem that is described in this article. Apply it only to
computers that are experiencing this specific problem. This fix may receive
additional testing. Therefore, if you are not severely affected by this problem,
Microsoft recommends that you wait for the next Microsoft Data Access Components
service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services
to obtain the fix. For a complete list of Microsoft Product Support Services
phone numbers and information about support costs, visit the following Microsoft
Web site:

   http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are ordinarily incurred for support calls
may be canceled if a Microsoft Support Professional determines that a specific
update will resolve your problem. The typical support costs will apply to
additional support questions and issues that do not qualify for the specific
update in question.

The English version of this fix has the file attributes (or later) that are
listed in the following table. The dates and times for these files are listed in
coordinated universal time (UTC). When you view the file information, it is
converted to local time. To find the difference between UTC and local time, use
the Time Zone tab in the Date and Time tool in Control Panel.

   Date         Version            Size     File Name     Platform
   ---------------------------------------------------------------
   12-Jul-2002  2000.081.9001.011   24,576  Odbcbcp.dll   x86
   12-Jul-2002  2000.081.9001.011  356,352  Sqlsrv32.dll  x86
   12-Jul-2002  2000.081.9001.011   90,112  Sqlsrv32.rll  x86



WORKAROUND
==========

To work around this problem, bind the parameter as SQL_C_CHAR (instead of as
SQL_C_WCHAR), and then pass non-Unicode data.

If you are using an Access linked table to update your SQL Server table, you
cannot use this workaround because Access always binds text parameters as
SQL_C_WCHAR.

STATUS
======

Microsoft has confirmed that this is a problem in the Microsoft products that
are listed at the beginning of this article.

MORE INFORMATION
================

Steps to Reproduce the Problem
------------------------------

1. Create the following tables in SQL Server:

   if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[repro]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
   drop table [dbo].[repro]
   GO

   CREATE TABLE [dbo].[repro] (
   	[name] [text] COLLATE SQL_Latin1_General_CP1_CI_AS NULL ,
   	[id] [char] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL 
   ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
   GO

   ALTER TABLE [dbo].[repro] WITH NOCHECK ADD 
   	CONSTRAINT [PK_repro] PRIMARY KEY  CLUSTERED 
   	(
   		[id]
   	)  ON [PRIMARY] 
   GO

   Insert Into Repro (name,id) Values ('abc','1234')

2. Use the following code to reproduce the problem:

   #include "stdafx.h"
   #include <stdio.h>
   #include <iostream.h>
   #include <windows.h>
   #include <sql.h>
   #include <sqlext.h>
   #include <sqltypes.h>

   void HandleError(SQLHANDLE	hHandle, SQLSMALLINT hType, RETCODE RetCode)
   {
   	SQLSMALLINT	iRec = 0;
   	SQLINTEGER	iError;
   	TCHAR		szMessage[1000];
   	TCHAR		szState[SQL_SQLSTATE_SIZE];

   	if (RetCode == SQL_INVALID_HANDLE)
   	{
   		fprintf(stderr,"Invalid handle!\n");
   		return;
   	}

   	while (SQLGetDiagRec(hType,
   			     hHandle,
   			     ++iRec,
   			     (SQLCHAR *)szState,
   			     &iError,
   			     (SQLCHAR *)szMessage,
   			     (SQLSMALLINT)(sizeof(szMessage) / 
   			     sizeof(TCHAR)),
   			     (SQLSMALLINT *)NULL) == SQL_SUCCESS)
   	{
   	fprintf(stderr,TEXT("[%5.5s] %s (%d)\n"),szState,szMessage,iError);
   	}

   }

   class ODBC_Class
   {
   	//attributes
   	public:
   	SQLHANDLE	henv;
   	SQLHANDLE	hdbc1;
   	SQLHANDLE	hstmt;
   	SQLRETURN	rc;

   	//methods
   	public:
   	ODBC_Class();
   	~ODBC_Class();
   	SQLRETURN	SendLongData();
   };

   ODBC_Class::ODBC_Class()
   {
     rc = SQL_SUCCESS;	//init the return code variable

     //Allocate an environment handle.
     rc = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);	//Allocate the env handle.

     //Set the ODBC application version to 3.x.
     if (rc ==SQL_SUCCESS)
   	rc = SQLSetEnvAttr(henv,SQL_ATTR_ODBC_VERSION, (SQLPOINTER)
                               SQL_OV_ODBC3, SQL_IS_UINTEGER);

     //Allocate a connection handle.
     if (rc == SQL_SUCCESS)
        rc = SQLAllocHandle(SQL_HANDLE_DBC,henv, &hdbc1);	
   }

   ODBC_Class::~ODBC_Class()
   {
   //Free the connection handle.
   if (hdbc1 != NULL)
   	SQLFreeHandle(SQL_HANDLE_DBC, hdbc1);

   //Free the environment handle.
   if (henv != NULL)
   	SQLFreeHandle(SQL_HANDLE_ENV, henv);
   }

   int main(int argc, char* argv[])
   {

   	SQLRETURN	rc		= SQL_SUCCESS;
   	CHAR		DBName[100]	= "YourDataBaseName";
   	CHAR		User[100]	= "YourUID";
   	CHAR		Password[100]	= "YourPassword";

   	CHAR		SQLstmt[255];
   	CHAR*		m_id		= ("1234");
   	CHAR*		m_name;
   	OLECHAR*	pSrc;
   	SQLINTEGER	bufsize		= 204801;
   	SQLINTEGER	ValSizeName = 5;
   	SQLINTEGER	ValSizeID   = SQL_DATA_AT_EXEC;
   	SQLINTEGER	paramMarker = 1;
   	

   	ODBC_Class Example; //Create an instance of the ODBC_Class to use.

   	if (Example.hdbc1 != NULL)
   	{
   	//Connect to the database.
   	  rc = SQLConnect(Example.hdbc1, (SQLCHAR*) DBName, SQL_NTS,
                                 (SQLCHAR*)User, SQL_NTS, (SQLCHAR*) Password,
                                 SQL_NTS);
   	  if (rc == SQL_SUCCESS || rc == SQL_SUCCESS_WITH_INFO)
   		cout << "Connected to " << DBName<< " \n\n" << endl;
   		

   	  //Allocate stmt handle.
   	  rc = SQLAllocStmt(Example.hdbc1, &Example.hstmt);	
   	  if ( rc == SQL_SUCCESS)
   	  {
   		UINT	info2 = 60;	//Set the timeout value in seconds.
   			
   		//Fill in the data "abcd...."
   		m_name = new char[bufsize];
   		for (int i = 0; i < bufsize; i++)
   		m_name[i] = (i % 26) + 65;

   		m_name[bufsize-1] = '#';
   		OLECHAR* m_olechar = new OLECHAR[bufsize*2];

   		int result = MultiByteToWideChar(CP_ACP, 0, m_name, -1,
                                                     m_olechar, bufsize*2);

   		//Bind the parameters.
   			
   		rc = SQLBindParameter(Example.hstmt,1,SQL_PARAM_INPUT,		
   	                             SQL_C_WCHAR, SQL_LONGVARCHAR,
                                        bufsize*2, 0, (SQLPOINTER)
                                        paramMarker, 0, &ValSizeName); 

   		if (rc != SQL_SUCCESS)
   		{
   		  HandleError(Example.hstmt,SQL_HANDLE_STMT, rc);
   		}
   	
   		rc = SQLBindParameter(Example.hstmt,2,SQL_PARAM_INPUT,
   		SQL_C_DEFAULT, SQL_CHAR, 4, 0, (SQLPOINTER) m_id, 4, NULL); 

   		strcpy(SQLstmt,"UPDATE repro SET name=? WHERE id=?");

   		ValSizeName = SQL_LEN_DATA_AT_EXEC(bufsize*2);
   		rc = SQLExecDirect(Example.hstmt, (SQLCHAR*) SQLstmt, 
                                      SQL_NTS);			
   		paramMarker = -1;
   		rc = SQLParamData(Example.hstmt, 
                                      (SQLPOINTER*)&paramMarker);

   		//Loop through and insert the data.
   		int j = 2*bufsize/8188;
   		int remains = bufsize*2;		
   		pSrc = m_olechar;			
   		for (int k=0; k<j; k++)
   		{
   		  remains -= 8188;
   		  rc =SQLPutData(Example.hstmt,(SQLPOINTER)pSrc , 8188);
   		  if (rc != SQL_SUCCESS)
                      HandleError(Example.hstmt,SQL_HANDLE_STMT, rc);
   		  pSrc += 4094; //Increment widechar pointer by 4094 = 8188 
                                   //bytes
   		  cout << rc << "\n";

   		}
   		rc =SQLPutData(Example.hstmt,(SQLPOINTER)pSrc , remains);

   		rc = SQLParamData(Example.hstmt, (SQLPOINTER*)paramMarker); 
   		if (rc != SQL_SUCCESS)
   		  HandleError(Example.hstmt, SQL_HANDLE_STMT, rc);
   		}
   		rc = SQLDisconnect(Example.hdbc1);
   	}
   	return (rc);
   }

   NOTE: Change the connection string as appropriate for your environment.

Additional query words: ODBC SQL driver

======================================================================
Keywords          :  
Technology        : kbSQLServSearch kbAudDeveloper kbSQLServ2000Search kbODBCSearch kbMDACSearch kbMDAC250 kbMDAC260 kbODBCSQLServ200080194 kbODBCSQLServ370 kbMDAC270
Version           : :2.5,2.6,2.7,2000.80.194,2000.80.380,2000.81.7713.0,3.7
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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