We now will compare definite articles with partitive articles to give you a better feeling for the differences.
Have a look at the following
sentences.
Example
J' aime le vin.
definite article
Je veux boire du vin.
partitive article
Having a closer look at them:
Example
J'
aime
le
vin.
I
like
---
wine.
Je
veux
boire
du
vin.
I
would like to
drink
(some)
wine.
Once the definite article was used, once the partitive article. In English both times no article would be used. Coming back to the definition as in here, partitive articles are used when 'some' can be used, because here it is about only part of a unity and not about the unity itself.
Other examples
Le
café
est
très
important
pour
l'
économie
de
l'
Amérique du Sud
The
coffee
is
very
important
for
the
economy
of
South America.
La
Colombie
exporte
du (de + le)
café
Colombia
exports
(some)
coffee.
Again we can see that the first sentence regards coffee as a unity, all of coffee is important in South America. And some of it (just a part) is exported by Colombia.