SharePoint site collection: relation with DB WSS_Content

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?

Regar开发者_开发技巧ds,

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.

SharePoint Terminology – Farms, Web Front Ends, Web Application and Sites

Each site collection can only use a single content database (though multiple site collections can use the same content database) – this has major design implications as there are maximum recommended sizes for a content database.