Sophie: freetds-doc-0.91-8.mga5 x86

freetds-doc-0.91-8.mga5.x86_64.rpm

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<HTML
><HEAD
><TITLE
>ODBC on Unix</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REL="HOME"
TITLE="FreeTDS User Guide"
HREF="index.htm"><LINK
REL="UP"
TITLE="How to get what works with it working"
HREF="software.htm"><LINK
REL="PREVIOUS"
TITLE="Qt"
HREF="qt.htm"><LINK
REL="NEXT"
TITLE="Troubleshooting"
HREF="troubleshooting.htm"><LINK
REL="STYLESHEET"
TYPE="text/css"
HREF="userguide.css"><META
HTTP-EQUIV="Content-Type"
CONTENT="text/html; charset=utf-8"></HEAD
><BODY
CLASS="SECT1"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
><SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> User Guide: A Guide to Installing, Configuring, and Running <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
></TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="qt.htm"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
>Chapter 7. How to get what works with it working</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="troubleshooting.htm"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="UODBC"
>ODBC on Unix</A
></H1
><P
><SPAN
CLASS="SYSTEMITEM"
>ODBC</SPAN
> has some issues on Unix, mainly due to lack of clean specifications.</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="UODBC.64"
>ODBC and 64-bit</A
></H2
><P
>ODBC was originally specified as 32-bit<A
NAME="AEN2887"
HREF="#FTN.AEN2887"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
>.  Its evolution to 64-bit took place in the absence of a good specification which led to conflicting declarations and associated problems.  For instance, some parameters are defined as SQLINTEGER but are used for pointer offsets.   But SQLINTEGER was (and remains) 32-bit, while pointer offsets must be 64-bit.  Also row numbers and some other formerly 32-bit quantities are now 64-bit.</P
><P
>If you use <SPAN
CLASS="PRODUCTNAME"
>unixODBC</SPAN
> Frediano would recommend at least version 2.2.14. Earlier versions have issues if used on 64-bit environments.</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="UODBC.WCHAR"
>sizeof(SQLWCHAR)</A
></H2
><P
>Under Windows <TT
CLASS="LITERAL"
>sizeof(wchar_t) == sizeof(SQLWCHAR) == 2</TT
> but on many Unix systems you have <TT
CLASS="LITERAL"
>sizeof(wchar_t) == 4</TT
>.  And some DMs decided to keep <TT
CLASS="LITERAL"
>sizeof(SQLWCHAR) == 2</TT
> (including <SPAN
CLASS="PRODUCTNAME"
>unixODBC</SPAN
>) while in other DM <TT
CLASS="LITERAL"
>sizeof(SQLWCHAR) == sizeof(wchar_t) == 4</TT
> (namely <SPAN
CLASS="PRODUCTNAME"
>iODBC</SPAN
>). This leads to incompatible ABIs between applications and drivers. If you compile the <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> ODBC driver using <SPAN
CLASS="PRODUCTNAME"
>iODBC</SPAN
> take care to ensure all drivers are compiled with the same header files.</P
><P
>Alternatively, compile <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> with both includes and rename the library to use two ABIs (for instance having a <TT
CLASS="FILENAME"
>libtdsiodbc.so</TT
> and a <TT
CLASS="FILENAME"
>libtdsuodbc.so</TT
>).</P
><P
>At the time of writing <SPAN
CLASS="PRODUCTNAME"
>Ubuntu</SPAN
> compiled Qt using <SPAN
CLASS="PRODUCTNAME"
>iODBC</SPAN
> but most packages use <SPAN
CLASS="PRODUCTNAME"
>unixODBC</SPAN
>. If you plan to use Qt with the <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> <SPAN
CLASS="SYSTEMITEM"
>ODBC</SPAN
> driver, you should have an <SPAN
CLASS="PRODUCTNAME"
>iODBC</SPAN
>-compatible driver. Also be aware that the QODBC Qt driver has problems with <SPAN
CLASS="PRODUCTNAME"
>iODBC</SPAN
> and <TT
CLASS="LITERAL"
>SQLWCHAR</TT
> (see <A
HREF="qt.htm"
>Qt</A
>). Due to these problems Frediano suggests not using this configuration (Qt database) on <SPAN
CLASS="PRODUCTNAME"
>Ubuntu</SPAN
> at this time.</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="UODBC.CHAR"
>Default charset</A
></H2
><P
>Character encoding is yet another trap.  ODBC makes no provision for specifying client character encoding. By default many DM converting from multi-byte to wide characters assume the client uses ISO 8859-1.  Even the <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> driver assumes ISO 8859-1 by default.  Also some DM have problems converting multi-byte encodings (like UTF-8), by assuming a byte can be converted to a single wide character (and vice versa). That creates problems if you use multi-byte encoding for <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> driver.</P
></DIV
></DIV
><H3
CLASS="FOOTNOTES"
>Notes</H3
><TABLE
BORDER="0"
CLASS="FOOTNOTES"
WIDTH="100%"
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN2887"
HREF="uodbc.htm#AEN2887"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>In fact, the earliest versions were 16-bit.</P
></TD
></TR
></TABLE
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="qt.htm"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.htm"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="troubleshooting.htm"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Qt</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="software.htm"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Troubleshooting</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>