one-to-many relationship between Mapserver and PostgreSQL

[Carlo Calvino]

Hello everybody,
I use Mapserver to publish some .SHP files. Let's take into consideration
a city layer. We use the Query function to see the data associated with
the city feature, for example, the name of the city, the population etc.
This data is stored in the shapefile. This works fine.
Furthermore, I use postgresql as a database. In one database I have a
table called "Monuments". For each city, there are several monuments. So
the relationship between the city and the monument is one-to-many. Inside
MapServer I wish to click on a city, and the result is the information
inside the shapefile, and also the monuments found in the postgresql
database. Of course, there is the same primary key inside the shapefile
table and the postgresql table, that is the name of the city. But How i
connect MapServer with PostgreSQL?