SharePoint site collection: relation with DB WSS_Content

Question

What's relationship between DB WSS_Content and SharePoint site collection? Is separated DB created per each site collection or a single DB can contain multiple collections?

Regards,

Answer 1

A single DB can contain multiple site collections. And a single web application can have multiple content databases.

Alternatively put: A web app 'contains' 0 or more content databases. A content database then contains 0 or more site collections.