Lisk is a blockchain application platform and crypto-currency, which offers an all round solution for Node.js and JavaScript developers to deploy their own blockchain applications.
You can find a very nice documentation about Lisk here but some useful iformation like the complete database structure are missing.
This gist aims at telling you more about where the Lisk blockchain is stored. The following notes are taken from the study of Lisk testnet 0.9.3a version.