Entity frameworks101

C# Entity Frameworks101

Sept 06, 2014By Rich Helton

What are Entity Frameworks(EF)?

•A Microsoft Object-Oriented Mapper (ORM) that generates the mapping of objects to SQL databases in Visual Studio.

Benefits of EF

Reduced Development time by generation of code and diagrams.

Integration into SQL Server and other Microsoft Tools and Frameworks, including Visual Studio.

Dealing with business objects instead of SQL code, better Object design.

Reduced security risks by not having dangling SQL scripts.

ASP.NET MVC

Is Microsoft's framework in support of the Model-View-Controller, the most popular design pattern in the world for rapid development.Entity Frameworks are used heavily with ASP.NET MVC, but they are a completely seperate framework that are used independently as well.

MVC Components

ASP.NET MVC benefits

Enables Test-Driven Development (TDD). Provides rapid development for developing

ASP.NET in Visual Studio. Supports IIS backend code for enhanced

functionality. Provides clean separation of concerns(SoC)

between different components.

What is TDD?

Test-Driven Development (TDD) is a software development process that relies on the repetition of a very short development cycle by utilizing automated test cases that defines new functionality and programming to the passing these tests.

EF Creation

DB Creation

We can create a DB from code,called code-first, including a table and populate the table will a fields.

By default, it will default to the local instance of .\SQLExpress.

We can also create tables and add fields from a Entity model as well, which is the mapping of the Entity objects.

Code-First DBContext

The recommended way to work with context is to define a class that derives from DbContext.

Use the DbSet properties that represent collections of the specified entities in the context.

DBContext Code

Here is an example of defining the DB structure through code.

Program Code

Example code of creating the DB, tables and adding fields.

Created the DB

Creating an EFModel

Creating a Project

Add a Data Model

Generate from DB

Set the Entity Name

We can visually view the models

We can delete the tables, not DB

Let's generate the tables from the models

Visual Studio builds the SQL for the table

Let's run the SQL from Visual Studio

The tables were built from the EF models

Populating the tables

The models have been previously created

Populating

Instead of DBContext, the generic context, we use the specific DB context that we defined when creating models, called MyNewTableEntities.

Let's add a row to the Address table

Done....