As far as I know it's possible that google won't index my pages in
Correct. And even if Google indexes your pages, it will be hard to rank. Unless your website is much more popular than the other websites with the same content.
How could I get my database indexed by google anyways?
I assume you do not just want your content to get indexed but also ranked. Mainly, there are three options:
- Become the authority. Get more and stronger backlinks than the other websites with the same content. Make sure your brand is perceived as the source/destination for this kind of content.
- Add a unique spin to the content. Add a video. Add a unique summary. Add user-generated pictures. Add reviews. Add top 10 tweets on the topic. Anything that is a) unique to your website and b) at least somewhat relevant for users. Ideally, it is super-relevant for users, of course!
- Aggregate the content in a unique way. Let's say you have a database of cars. Instead of getting the individual car descriptions indexed, which are already available on 1000 other websites, create filtered lists like "Cars with large tyers" or "electric SUVs" or "cars released in 1997" or "cars with tv screens". You can list all appropriate cars and tease some of their content on these lists. The individual car pages you can either set to no-index or just let them be and hope Google will index some someday.
Does it make sense to mark my sites as canonical URLs?
If you can get other websites to point a canonical tag to your website, yes! Otherwise, no. For hygiene, a self-referencing canonical is still a good idea. But it will not solve your problem.