The Umbraco front end doesn't use the DB, it uses an XML file. There is an older Linq2Umbraco extension that allows you to query certain DocumentTypes with Linq, although I'm not sure how well supported it is now. If you're using the most up to date versions of Umbraco then you can use the Razor syntax which supports Linq syntax.
I wouldn't recommend using Linq or EF to access the Umbraco database directly, as you may run into issues. You'd be better off using the API instead. If you're talking about for custom tables that you want to add to Umbraco to store your own data, then that should be OK though.
DB
I can use Linq for work with database or entity framework?
The Umbraco front end doesn't use the DB, it uses an XML file. There is an older Linq2Umbraco extension that allows you to query certain DocumentTypes with Linq, although I'm not sure how well supported it is now. If you're using the most up to date versions of Umbraco then you can use the Razor syntax which supports Linq syntax.
I wouldn't recommend using Linq or EF to access the Umbraco database directly, as you may run into issues. You'd be better off using the API instead. If you're talking about for custom tables that you want to add to Umbraco to store your own data, then that should be OK though.
Hope that helps!
Have a look at this topic if you want to query custom tables: http://our.umbraco.org/forum/developers/extending-umbraco/27331-ORMT-SQL.
Jeroen
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