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>FreeTDS</SPAN
> User Guide: A Guide to Installing, Configuring, and Running <SPAN
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>FreeTDS</SPAN
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>Chapter 4. Preparing ODBC</TD
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><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="ODBCDIAGNOSE"
>Troubleshooting ODBC connections</A
></H1
><P
>Supposing everything compiles and installs without trouble, how do you know if your ODBC setup  works?  Or, if you know it doesn't, what then?</P
><P
>First, try to connect with <B
CLASS="COMMAND"
>tsql</B
>.  If you're intending to use <TT
CLASS="FILENAME"
>freetds.conf</TT
>, exercise it with
			<B
CLASS="COMMAND"
>tsql -S <TT
CLASS="REPLACEABLE"
><I
>servername</I
></TT
></B
>.  If not, use
			<B
CLASS="COMMAND"
>TDSVER=7.0 tsql -H <TT
CLASS="REPLACEABLE"
><I
>hostname</I
></TT
> -p <TT
CLASS="REPLACEABLE"
><I
>port</I
></TT
></B
></P
><P
>If <B
CLASS="COMMAND"
>tsql</B
> works and <B
CLASS="COMMAND"
>isql</B
> doesn't, you've isolated the problem to the ODBC setup.  <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> might have some interoperability problems, but mere connection to the database isn't one of them!  If <B
CLASS="COMMAND"
>tsql</B
>
			doesn't work, turn on logging with <CODE
CLASS="ENVAR"
>TDSDUMP</CODE
>.  The log will tell you what TCP/IP name (and address) <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> is attempting to connect to, and what version of the TDS protocol it's using.</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="WITH.IODBC"
>With iODBC</A
></H2
><P
>	<SPAN
CLASS="PRODUCTNAME"
>iODBC</SPAN
> comes with a sample command line query program called <B
CLASS="COMMAND"
>odbctest</B
>, located in the <TT
CLASS="FILENAME"
>iodbc/samples</TT
> directory.  Using this program you can get a listing of DSNs, connect, and issue queries.  
	<DIV
CLASS="TIP"
><P
></P
><TABLE
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><IMG
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HSPACE="5"
ALT="Tip"></TD
><TD
ALIGN="LEFT"
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><P
>For debugging purposes, you may wish to link a program such as <B
CLASS="COMMAND"
>odbctest</B
> directly to <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> instead of to the driver manager.  <A
NAME="AEN2052"
HREF="#FTN.AEN2052"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
>  To do so, compile and install the <SPAN
CLASS="SYSTEMITEM"
>ODBC</SPAN
> driver with <SPAN
CLASS="PRODUCTNAME"
>iODBC</SPAN
> as normal <A
NAME="AEN2058"
HREF="#FTN.AEN2058"
><SPAN
CLASS="footnote"
>[2]</SPAN
></A
>, then compile and link the program:
				
				<DIV
CLASS="EXAMPLE"
><A
NAME="E.G.ODBCTEST.NODM"
></A
><P
><B
>Example 4-7. Compile <TT
CLASS="FILENAME"
>odbctest</TT
> without a driver manager.</B
></P
><PRE
CLASS="SCREEN"
>	<SAMP
CLASS="PROMPT"
>$ </SAMP
><KBD
CLASS="USERINPUT"
>make odbctest.o</KBD
>
	<SAMP
CLASS="PROMPT"
>$ </SAMP
><KBD
CLASS="USERINPUT"
>gcc -g -o odbctest odbctest.o /usr/local/freetds/lib/libtdsodbc.a</KBD
></PRE
></DIV
>
	
				Now you can run <B
CLASS="COMMAND"
>gdb</B
> or another debugger and set breakpoints on functions in the library without the driver manager getting in the way.</P
></TD
></TR
></TABLE
></DIV
></P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="WITH.UNIXODBC"
>With unixODBC</A
></H2
><P
>Try <B
CLASS="COMMAND"
>isql -v <TT
CLASS="REPLACEABLE"
><I
>dsn</I
></TT
> <TT
CLASS="REPLACEABLE"
><I
>username</I
></TT
> <TT
CLASS="REPLACEABLE"
><I
>password</I
></TT
></B
>, and have a look at the log.  See if the right address and TDS version are being used.  Adjust to taste.</P
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="WITH.UNIXODBC.OSQL"
>Use <B
CLASS="COMMAND"
>osql</B
></A
></H3
><P
>The <B
CLASS="COMMAND"
>osql</B
> utility is a Bourne shell script that checks your ODBC configuration.  If it approves, it invokes the unixODBC isql utility.  Cf. <B
CLASS="COMMAND"
>man osql</B
> for details on its use.
					
					<DIV
CLASS="EXAMPLE"
><A
NAME="E.G.ODBCDIAGNOSE.OSQL"
></A
><P
><B
>Example 4-8. Use <B
CLASS="COMMAND"
>osql</B
> to test the ODBC setup.</B
></P
><PRE
CLASS="SCREEN"
>	<SAMP
CLASS="PROMPT"
>$ </SAMP
><KBD
CLASS="USERINPUT"
>make odbctest.o</KBD
>
	
	<SAMP
CLASS="PROMPT"
>$ </SAMP
><KBD
CLASS="USERINPUT"
>osql -S machine -U mr_ed -P hayseed</KBD
>
	looking for odbc.ini and odbcinst.ini in /usr/local/etc
	reading "/usr/home/mr_ed/.odbc.ini"
	[machine] found in "/usr/home/mr_ed/.odbc.ini"
	found this section:
	[machine]
	Database = testdb
	Servername = machine
	Trace           = Yes
	TraceFile       = /tmp/unixodbc.trace

	looking for driver for DSN [machine]
	no driver mentioned for [machine] in .odbc.ini
	looking for driver for DSN [default]
	driver "FreeTDS" found for [default] in .odbc.ini
	found driver named "FreeTDS"
	FreeTDS is not a readable file
	looking for entry named [FreeTDS] in /usr/local/etc/odbcinst.ini
	driver "/usr/local/lib/libtdsodbc.so" found for [FreeTDS] in odbcinst.ini
	/usr/local/lib/libtdsodbc.so is a readable file
	Using ODBC-Combined strategy
	FreeTDS servername is "machine" (from /usr/home/mr_ed/.odbc.ini)
	looking for [machine] in /usr/home/mr_ed/.freetds.conf
	"/usr/home/mr_ed/.freetds.conf" is a readable file
	found this section:
	[machine]
	host = machine.example.com
	port = 2500
	tds version = 7.1

	machine.example.com has address 10.82.32.177

	DSN: machine
	Driver: /usr/local/lib/libtdsodbc.so
	Server's hostname: machine.example.com
	Address: 10.82.32.177

	Attempting connection as mr_ed ...
	+ exec isql machine mr_ed hayseed -v
	+---------------------------------------+
	| Connected!                            |
	|                                       |
	| sql-statement                         |
	| help [tablename]                      |
	| quit                                  |
	|                                       |
	+---------------------------------------+
	SQL&#62;</PRE
></DIV
></P
><P
>The reader is here advised that the <B
CLASS="COMMAND"
>isql</B
> that comes with many versions of unixODBC will truncate text and surprise in other ways without warning.  If it behaves strangely, try <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
>'s <B
CLASS="COMMAND"
>bsqlodbc</B
> before you decide you've found a <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> bug.  </P
></DIV
></DIV
></DIV
><H3
CLASS="FOOTNOTES"
>Notes</H3
><TABLE
BORDER="0"
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WIDTH="100%"
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN2052"
HREF="odbcdiagnose.htm#AEN2052"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>Why?  Once the program is started in the debugger, the driver entry points become viable breakpoints.  Because the DM loads the driver dynamically with <CODE
CLASS="FUNCTION"
>dlopen(3)</CODE
>, no driver addresses even <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>exist</I
></SPAN
> until the runtime linker loads it. </P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN2058"
HREF="odbcdiagnose.htm#AEN2058"
><SPAN
CLASS="footnote"
>[2]</SPAN
></A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>When linking directly to <SPAN
CLASS="PRODUCTNAME"
>FreeTDS</SPAN
> you still need the Driver Manager's header files.</P
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