DIY Database?

Given that you're asking about buying existing products as well as asking about creating your own I assume you're choosing between those options?

You could make your own front end to ODBC.
Or are you interested in making your own low-level db implementation? In that case you have to worry about... Encryption, Authorisation, B-Trees, Disk and memory allocation, defragmentation, API, etc etc...

Go for the pre-made I think.

yea, thats what i was affraid of lol!

i just kinda want to make a lightweight database as a kind of proof of concept.

but cheers for the reply.
-Danu

If you want a lightweight, ready-made database you could always look up sqlite. It is pretty simple to use!

You need the storage engine, which handles storing of the data.. You also need a query engine which interacts with the storage engine to return data - typically you'd have an API to interact directly with the query engine or an SQL compilant interface to it, allowing the user to throw SQL queries at it and get them back. Naturally you'd need some form of driver to allow software to connect to it and interact with your database. I'm not even going to touch on the more detailed aspects of security, recovery, ACID and all that stuff we take for granted.

You'll need to start researching RDBMS theory (link), perhaps downloading SQLite is one of the first steps you should take as you get to see full source to a small database system.