asp.net - what is entity framework ? why should i use it ? can i use it without linq? -

i have read documents entity framework, came know makes entities our database(orm).

i tried go deeper don't satisfactory answer.

i want know why , when entity framework used? linq necessary framework?

and silly question

what difference in "use" between 3-tier architecture , entityfrmaework ?

any related document helpful

thanks in advance.

i came know makes entities our database(orm).

:-/

actually ef make entities db model if decide start call db first approach. doing so, ef somehow reverse engineer db model , create entities in edmx file become business model. best practice change generated entities , modify them in order make them real business model.

from point of view, db model , business model 2 different things they’re not designed same goal: db model designed able persist , fetch db data efficiently , business model’s goal conceptualize business needs , must fit how application manipulate it. nice thing edmx 3 parts file 1 distinct area representing db model, 1 business/conceptual model , last not least: mapping between two! allows have "real" business model , able persit data in different structure.

there lot of documentation describing different ef approaches; starting point should ado .net site.

here, you’ll find things you’ll need started including how choose between different approaches.

now, other questions:

i want know why , when entity framework used?

ef , other orms used in order create abstraction layer on top of db. lets manipulate objects rather accessing directly db. ef data access layer (dal) of application , entities should business/domain model. 1 of advantages improve productivity taking care of db related code on other side, you’ll have pay attention kind of t-sql code generated dynamically. orm becomes easy generate ugly queries lead dramatic performances. please search on google find out best practices , things avoid when working orms.

what difference in "use" between 3-tier architecture , entityfrmaework ?

as said, ef dal. ef somehow 1 of tiers in architecture.

hope helps!