Explain composite primary key, including an example
Explain composite primary key, including an example

jwarwick/phoenix,phoenixframework/phoenix,0x00evil/phoenix,mobileoverlord/phoenix,rafbgarcia/phoenix,Joe-noh/phoenix,evax/phoenix,korobkov/phoenix,trarbr/phoenix,Gazler/phoenix,mitchellhenke/phoenix,phoenixframework/phoenix,gjaldon/phoenix,bsmr-erlang/phoenix,evax/phoenix,nshafer/phoenix,eksperimental/phoenix,korobkov/phoenix,Gazler/phoenix,optikfluffel/phoenix,Kosmas/phoenix,mschae/phoenix,Kosmas/phoenix,phoenixframework/phoenix,pap/phoenix,keathley/phoenix,rafbgarcia/phoenix,nshafer/phoenix,pap/phoenix,optikfluffel/phoenix,trarbr/phoenix,gjaldon/phoenix,Joe-noh/phoenix,mobileoverlord/phoenix,0x00evil/phoenix,stevedomin/phoenix,stevedomin/phoenix,mitchellhenke/phoenix,bratsche/phoenix_guides,eksperimental/phoenix,bsmr-erlang/phoenix,jwarwick/phoenix,michalmuskala/phoenix,dmarkow/phoenix,keathley/phoenix,nshafer/phoenix,mschae/phoenix,wsmoak/phoenix_guides,optikfluffel/phoenix,michalmuskala/phoenix,dmarkow/phoenix,rafbgarcia/phoenix,0x00evil/phoenix