We can get all webs and site templates under site collection by using the a small script. Read full article to know in details.
For Particular Requirement, client want to dedicate a database for a single site collection. When we create a site collection from central admin, site is placed automatically in any available content database. To prevent any other sites to be created on the particular content database, We can set maximum number of site collection on particular content database. read full article for details.