<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Thanks Oliver.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>No, not in a thread. There are no additional threads created in this application. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri",sans-serif'> oliver [mailto:oliver.schoenborn@gmail.com] <br><b>Sent:</b> Friday, October 7, 2016 9:55 PM<br><b>To:</b> Pradip Dattani <pradip.dattani@ntlworld.com>; pyqt@riverbankcomputing.com<br><b>Subject:</b> Re: [PyQt] ODBC error while accessing SQL Server from PyQt application<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p>Is the query executed in GUI thread? <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Fri, Oct 7, 2016, 16:23 Pradip Dattani <<a href="mailto:pradip.dattani@ntlworld.com">pradip.dattani@ntlworld.com</a>> wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>We have written our first PyQt (4.6) application. However we have hit a serious road block due to an intermittent database access error.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>The error we see is: <b>“[Microsoft][ODBC Driver Manager] Invalid string or buffer length”.</b><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>The application has a number of Tableviews, drop down lists, TreeWidget etc. Most of these are populated dynamically by querying the database.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Database queries are made through custom API code that uses SqlAlchemy. We do not use QtSql module.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>We see this error only when executing a database query from within PyQt application. It’s very random and therefore not a reproducible error. Has anyone seen this before and got any pointers to resolve such issues. We have tried to google. We see many posts but no answers. <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Are there any good practices we should observe when querying database from within PyQt application.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Thank you in advance. <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Regards,<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Pradip<o:p></o:p></p></div></div><p class=MsoNormal>_______________________________________________<br>PyQt mailing list <a href="mailto:PyQt@riverbankcomputing.com" target="_blank">PyQt@riverbankcomputing.com</a><br><a href="https://www.riverbankcomputing.com/mailman/listinfo/pyqt" target="_blank">https://www.riverbankcomputing.com/mailman/listinfo/pyqt</a><o:p></o:p></p></blockquote></div><div><p class=MsoNormal>-- <o:p></o:p></p></div><div><div><p class=MsoNormal>Oliver<o:p></o:p></p></div></div></div></body></html>