Linux Appliance Design

D.3. A tbl2filed Example

Let's look at a complete example by continuing with the nameserver configuration for Laddie. The /etc/resolv.conf file on a running Laddie system looks like this:

nameserver 204.117.214.10
nameserver 199.2.252.10
nameserver 65.173.40.10

Our goal is to be able to read the first DNS nameserver with a SELECT statement as follows:

psql -h localhost -p 8885
> SELECT * FROM tbl2field where name = "nameserver_1";
> \q

Similarly, to modify the second DNS server, Laddie uses the following UPDATE statement:

psql -h localhost -p 8885
> UPDATE tbl2field SET value="192.168.1.1"
>   WHERE name=resolv AND field="nameserver_2";
> \q

You can verify the above by booting the Laddie CD, exiting from the framebuffer menu, logging in as root, ...