Blockchain is a new type of database. It does not require a central medium for transmitting data. The reliability of data is one on one and there is no risk of a third-party transmission involved.
SQL and Non-SQL databases use a centralized system to store data. The data is stored in a structured format governed by an administrator. The administrator allocates permissions on managing the data.
Comparison:
In general, regular database and blockchain can perform the same way except for the medium for governing the data is eliminated in blockchain. Secondly in a database the data is editable. In a blockchain the data is non editable. Thirdly in traditional database old entries can be erased if not required but in blockchain all entries will relationally exist.
Security wise the central server of a database is the only target area where all data is stored whereas in blockchain every data is a referral to its previous entry like a chain of entries representing a transaction. In a database the administrator assigns permission to read write data onto a database wherein blockchain every entry requires a consensus from the previous made referral entries. In database behavior wise there exists one central admin assigning permission but in blockchain every node is an admin and has to provide consensus for data entry. In a database if there occurs an error or updating it consumes a lot of time and point of failure is possible, on the other hand a blockchain there are multiple reference nodes to every entry and the point of failure is eliminated.
Database uses CRUD – Create, read, update and delete and in blockchain uses only append. The database requires large volume of data stored across a centralized system. Blockchain does not require large storage area, but the processing time is slower as there is signature verification, consensus and redundancy mechanism involved.
Comparatively regular database and blockchain have their own pros and cons and it depends on how adaptive the nature of the usage is. Compared to database the blockchain is more drastically trending into industries than the traditional centralized system which has been there for many years.