I wanted to know what are the differences between IPFS, interplanetary file system and a block chain database like IPDB and BigChainDB
IPFS is a cache layer. It does not guarantee the storage of the content. It is just a way to address and cache online content. Think it as a more web browser friendly BitTorrent.
BigChainDB is a SQL-like database where clients can sign the transaction and they can be guaranteed to come from a certain key holder. A super admin cannot manipulate the data without leaving a trace. BigchainDB does not have any kind of economic guarantees that the system keeps running, you still need to have a sysadmin and pay servers.
Public blockchains have some sort of economic and reward mechanism, which incentives block producing and thus guarantees persistence, immutability and other features of the chain. Having those guarantees makes it suitable as a transfer-of-value and store-of-value network, which the two options above are not.