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EF – One of Microsoft’s ORMs Entity Framework – EF (ORM) Juhani Välimäki 21.5.2013 OOP - Object-oriented Programming : Member : Idea Member will have Ideas collection, Idea will get Members collection and it is enough to add to one of these, the EF maintains the other automatically. The EF context must know both objects = they must be fetched from same context object or the new created object must be attached to the same EF data context (object) In the web application - Entity objects from EF - Many-to-Many relatioships are ok - Pure join tables disappear. - EF manages many-tomany relationships Microsoft Entity Framework – EF = one of Microsoft’s ORMs (EF data model description file .edmx) ORM – Object Relational Mapping E.g. Hibernate, NHibernate, Java Persistence API, … Driver, adapter etc. libraries In the database - Tables - Only 1-to-Many DBMS, e.g. MS SQL relatioships Server, Oracle, IBM DB2 - Pure join tables exist for linking many-to-many RDB RDB – Relational Database
