the hard bit is constructing your dbs in a way that makes it "impossible" to use without adopting the prescribed method you provide for its use/licensing.
and then it depends how much work a "hacker" is prepared to spend in reverse engineering (or otherwise circumventing security) for your application, given that nothing is completely uncrackable.
This is undeniably true, but there are ways to make things difficult for the hacker. And the smart thing is not to publicize what they are. I got burned early in my career in not getting paid for a large software project and since I have adopted methods which have served me well. One of the defense mechanisms is a simple date expiry, which is not removed until the bill has been paid in full. Works well.
True story: In the late eighties, a financial house in Montreal ordered a financial analysis package from me which I delivered alas for which they omitted to pay me the "other half" of my fee. They did not omit selling the product to ~ two dozen of their clients. In six months, the package blew up with the firm's Copyright text disappearing and a message expressing regret for the inconvenience but there was money owed on the contract for the product and the software will now shut down.
By a coincidence, a friend of mine was one of the people contacted to remove the intercepting code. He couldn't and contacted me (not knowing I wrote the program) with an offer of nearly double of what the miscreants owed me if I would crack it. I said 'sure' and presented him with a 'cracked' version a day later. He paid me. Of course all I did was pushed the date of expiry ahead by six months. In due time, I received a call from one of the principals (he traced me to Ottawa where I moved), protesting their innocence and would I give them the source code as we agreed, if they were to pay me what I claimed they owed. We had an satisfaction agreement drafted by a lawyer, and I gave them the source code for their product. Obviously, it came without the intercept code (written in 8086 assembler). My copyright!
Best,
Jiri