findAllByPk with a primary key from 2 or more fields

I’m trying to fetch some data using findAllByPk with a primary key which consists of two fields:

Some_model::model ()->findAllByPk ( array ( 'field1' => 1 ) );

Running this code I always get an error like: The value for the column "field2" is not supplied when querying the table "Some_model".

Does anyone have an idea about how to query the table based on a single field?

try findAllByAttributes().

I could also do findAllBySql but I’m more interested to know if this actually works with my current table setting (findAllByPk)