Accessing Database without using SQL This might be some ambiguous but I have not much info about this so I need some start point;

As a general idea; in conventional RDBMS', there are a DB engine and storage of data. We use the language 'SQL' to access these datas on the DB. To access datas, is there other ways different from using SQL queries? Can we 'fire' events of DB engine without using SQL and get the datas in the storage? If yes, how?
You can also use your favorite hex editor :). This can even be a good learning lesson to see how things work under the hood. For example, you could have a look at those posts/videos:


How does sql server store data by Brent Ozar;
Corrupting Databases for Dummies- Hex Editor Edition by Kendra Little.


But using a high level language like SQL or your vendors implementation (tsql, pl/sql...) makes things so much easier.