| FreeTDS User Guide: A Guide to Installing, Configuring, and Running FreeTDS | ||
|---|---|---|
| Prev | Chapter 4. Preparing ODBC | Next |
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?
First, try to connect with tsql. If you're intending to use freetds.conf, exercise it with tsql -S servername. If not, use TDSVER=7.0 tsql -H hostname -p port
If tsql works and isql doesn't, you've isolated the problem to the ODBC setup. FreeTDS might have some interoperability problems, but mere connection to the database isn't one of them! If tsql
doesn't work, turn on logging with TDSDUMP. The log will tell you what TCP/IP name (and address) FreeTDS is attempting to connect to, and what version of the TDS protocol it's using.
iODBC comes with a sample command line query program called odbctest that is located in the iodbc/samples directory. Using this program you can get a listing of DSNs, connect, and issue queries. It is often useful to compile a program such as this directly against the FreeTDS driver instead of using a driver manager. This makes it simpler to debug if something goes wrong. To do so, simply compile and install the ODBC driver with iODBC as normal [1], then compile and link the program directly:
Example 4-7. Compile odbctest without a driver manager.
$ make odbctest.o $ gcc -g -o odbctest odbctest.o /usr/local/freetds/lib/libtdsodbc.a
-g is important to keep the symbol tables for debugging purposes. Now you can run gdb or another debugger and set breakpoints on functions in the library without the driver manager getting in the way.
Try isql -v dsn username password, and have a look at the log. See if the right address and TDS version are being used. Adjust to taste.
The osql utility is a Bourne shell script that checks your ODBC configuration. If it approves, it invokes the unixODBC isql utility. Cf. man osql for details on its use.
Example 4-8. Use osql to test the ODBC setup.
$ make odbctest.o
$ osql -S machine -U mr_ed -P hayseed
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 = 8.0
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>| [1] | When compiling directly to FreeTDS you still need the Driver Manager's header files. |