Entity Framework
Although Entity Framework 6 is still supported, it is no longer being developed and will only receive fixes for security issues.
[5] The Entity Framework is a set of technologies in ADO.NET that supports the development of data-oriented software applications.
Architects and developers of data-oriented applications have typically struggled with the need to achieve two very different objectives.
[6] Many object–relational mapping (ORM) tools (aka "object–relational managers") have been developed to enable developers to work with data in the form of domain-specific objects and properties, such as customers and customer addresses, without having to concern themselves with the underlying database tables and columns where this data is stored.
Entity Framework is the ORM solution currently promoted for use within the Microsoft development stack.
This version was widely criticized, even attracting a 'vote of no confidence' signed by at least one thousand developers.
A refresh of version 4.1, named Entity Framework 4.1 Update 1, was released on July 25, 2011.
[14] Microsoft then decided to modernize, componentize and bring .NET cross-platform to Linux, OSX and elsewhere, meaning the next version of Entity Framework would be a complete rewrite.
[16] It was originally named Entity Framework 7, but was renamed to highlight that it was a complete rewrite rather than an incremental upgrade and it doesn't replace EF6.
While Entity Framework Core 1.0 shares some conceptual similarities with prior versions of Entity Framework, it was a completely new codebase designed to be more efficient, powerful, flexible, and extensible, running on Windows, Linux and OSX, and supporting a new range of relational and NoSQL data stores.
[citation needed] The "Model First" approach is not going to be supported in EF Core version.
Entities represent individual objects that form a part of the problem being solved by the application and are indexed by a key.
Queries in eSQL, if required, are then translated to the native SQL flavor of the underlying database.
All EntityTypes belong to some namespace, and have an EntityKey property that uniquely identifies each instance of the entity type.
Multiple instances of one entity type can be stored in collections called EntitySets.
In future releases, other kinds of relationship types such as Composition, or Identification, may be introduced.
[citation needed] ADO.NET Entity Framework uses an XML based Data Definition Language called Schema Definition Language (SDL) to define the EDM Schema.
The SDL defines the SimpleTypes similar to the CTS primitive types, including String, Int32, Double, Decimal, Guid, and DateTime, among others.
An Enumeration, which defines a map of primitive values and names, is also considered a simple type.
As an example, an entity can be denoted in SDL as:[39] A relationship type is defined as specifying the end points and their multiplicities.
It differs from SQL in that it does not have explicit constructs for joins because the EDM is designed to abstract partitioning data across tables.
Like ADO.NET data providers, an EntityClient provider is also initialized using a Connection object, which in addition to the usual parameters of data store and authentication info, requires the SDL schema and the mapping information.
[citation needed] Entity SQL enhances SQL by adding intrinsic support for:[citation needed] Canonical functions are supported by all Entity Framework compliant data providers.
When ADO.NET data provider receives a function, it translates it to the desired SQL statement.
[citation needed] In the Entity Framework v4 new methods ExecuteStoreQuery() and ExecuteStoreCommand() were added to the class ObjectContext.
