ADO.NET Entity Framework - Architecture

Architecture

The architecture of the ADO.NET Entity Framework, from the bottom up, consists of the following:

• Data source specific providers, which abstract the ADO.NET interfaces to connect to the database when programming against the conceptual schema.
• Map provider, a database-specific provider that translates the Entity SQL command tree into a query in the native SQL flavor of the database. It includes the Store-specific bridge, which is the component responsible for translating the generic command tree into a store-specific command tree.
• EDM parser and view mapping, which takes the SDL specification of the data model and how it maps onto the underlying relational model and enables programming against the conceptual model. From the relational schema, it creates views of the data corresponding to the conceptual model. It aggregates information from multiple tables in order to aggregate them into an entity, and splits an update to an entity into multiple updates to whichever table(s) contributed to that entity.
• Query and update pipeline, processes queries, filters and updates requests to convert them into canonical command trees which are then converted into store-specific queries by the map provider.
• Metadata services, which handle all metadata related to entities, relationships and mappings.
• Transactions, to integrate with transactional capabilities of the underlying store. If the underlying store does not support transactions, support for it needs to be implemented at this layer.
• Conceptual layer API, the runtime that exposes the programming model for coding against the conceptual schema. It follows the ADO.NET pattern of using Connection objects to refer to the map provider, using Command objects to send the query, and returning EntityResultSets or EntitySets containing the result.
• Disconnected components, which locally cache datasets and entity sets for using the ADO.NET Entity Framework in an occasionally connected environment.
• Embedded database: ADO.NET Entity Framework includes a lightweight embedded database for client-side caching and querying of relational data.
• Design tools, such as Mapping Designer, are also included with ADO.NET Entity Framework, which simplifies the job of mapping a conceptual schema to the relational schema and specifying which properties of an entity type correspond to which table in the database.
• Programming layer, which exposes the EDM as programming constructs which can be consumed by programming languages.
  • Object services, automatically generate code for CLR classes that expose the same properties as an entity, thus enabling instantiation of entities as .NET objects.
  • Web services, which expose entities as web services.
• High-level services, such as reporting services which work on entities rather than relational data.