Other than using the existing known facts to label the text corpora in a distant supervision setting (Bunescu and Mooney, 2007;Mintz et al., 2009;Riedel et al., 2010;Ritter et al., 2013), an existing knowledge base is typically not involved in the process of relation extraction.
this paradigm has started to shift recently, as researchers showed that by taking existing facts of a knowledge base as an integral part of relation extraction, the model can leverage richer information and thus yields better performance.