Model First Approach in MVC

Step 1: 

Open VS 2010 > File > New Project > Select Visual C# or Visual Basic Windows Template and 

select an Empty Project . I am calling this project ‘ModelFirstEF’. 

Right click the Project in Solution Explorer > Add > New Item > Data Template > ADO.NET Entity 

Data Model. Click Add.

The Entity Data Model Wizard appears. Select ‘Empty Model’ and click on Finish.

Step 2: 

The wizard creates a new conceptual model with an empty Data Model Designer to create your 

Entity Data Model (EDM).

Drag and drop an Entity from the Toolbox to the Designer as shown below. You can even right click 

the designer > Add Entity

Rename ‘Entity1’ to ‘Employee’. The Id property you see above is the Entity Key (Primary Key) of 

this entity. I will rename it to ‘EmployeeId’ in the properties window. Also observe that it’s Type is 

set to ‘Int32’ and since this is an identity key, its ‘StoreGeneratedPattern’ is automatically set to 

‘Identity’.

You can add additional properties like FirstName (string), LastName (string), Age (Int16) etc. by 

right clicking the Entity in the designer > Add > Scalar Property

Step 3: 

Let us add one more entity called ‘Department’. This time we will do it from the designer. Right 

click the designer > Add > Entity

The ‘Add Entity’ dialog appears. Type ‘Department’ in the Entity name field and select the box 

‘Create Key Property’ to create an Entitykey. Call it ‘DepartmentId’ and set its property type as 

Int32.

Click OK and a new Department entity will appear on the design surface. Add two additional 

properties DeptName (string) and EmployeeId (Int32) to the Department Entity.

Step 4:

 Our next step is to create a One-to-many relationship between Employee and Department. Each 

Department can have many Employees, but one Employee can belong to only one Department. 

Using the Association tool in the Toolbox, select the EmployeeId property in the Employee entity, 

hold the left mouse button down and drag it to the DepartmentId property in the Department entity.

Update: I should have added the DepartmentId in the Employee table, but for this example just 

assume the opposite. It is a typo. 

Alternatively, you can also right click the Employee Entity > Add > Association to create a 

relationship.

Your conceptual model is ready now! Our next step is to generate the database from the model

Generate Schema and Database from Model 

Step 5: 

I have gone ahead and created an Empty database called ‘EFDB’ in my SQL Server box. To generate 

a Database from the model, right click the designer > Generate Database from Model..

Note: I find this amusing! Although the option says ‘Generate Database from Model’, an empty or 

an existing database ‘must’ exist before clicking this option. I think the Database must exist due to 

the Connection Settings that we will establish in the next step. We need to specify a target database 

there, so the database must exist beforehand. Also the DDL script that gets generated does not 

include the script to generate a new database.

Step 6:

 The Generate Database Wizard appears. Click on ‘New Connection’ and fill the Connection 

properties as shown below. Test the Connection and Click OK.

Click Next in the wizard to preview the DDL that will be generated

Click Finish to add the generated script to your project. Once you click Finish, an EntityConnection 

string is added to your config file and the DDL, SSDL and MSL files are created (read my previous 

articleExploring the Entity Data Model (EDM) to know what SSDL and MSL are).

Step 7:

 All you need to do now is run the database script by clicking on the Green Arrow in a query window 

(Ctrl+Shift+E) to create the Employee and Department tables in the database EFDB.

If everything’s ok, you will see the message ‘Command(s) executed successfully. 

How did the DDL Scripts get generated from the model?

      If you are wondering what went behind the scenes to generate the database, then I would strongly 

recommend you to read my previous article Exploring the Entity Data Model (EDM) where I 

discussed the role of .EDMX and its files SSDL, CSDL and C-S mapping. These files play a role not 

only in generating a model from the database, but also vice-versa, i.e. generating a database from a 

model. Observe the properties of Model1.edmx as shown below, especially the DDL Generation 

Templateproperty.

   This property specifies a T4 template (.tt) file. The T4 Templates reads the .edmx with the help of 

the TablePerTypeStrategy.xaml (windows workflow file) and generates the T-SQL code (DDL 

script) that we just saw.As given in the msdn documentation “T4 is shorthand for the Text Template 

Transformation Toolkit and is a Microsoft technology explicitly designed to make text file creation 

such as code generation straightforward using templates. It is a mixture of processing logic and text 

to emit with the idea that the text can be created from the template by substituting values in it 

programmatically. This is similar in principle to XSLT but T4 allows the blending of .NET code and 

text mark-up to be combined seamlessly and it is used extensively in Visual Studio 2010”

        The best part is that you can modify this template and customize the DDL generated. You can 

download the Entity Designer Database Generation Power Pack which contains Windows 

Workflows and T4 Templates to manage database generation strategies. Anyways we will explore 

this topic again in one of the future articles. 

Limitations of the Model-First development 

There are two major limitations of the Model-First development that you should keep in mind (we 

will also see how to overcome them)

You cannot update the database and expect the changes to be updated in the model. Currently it’s not

possible out-of-the-box through EF 4.0.

If you go ahead and populate the database with data and then at a later stage change your model, then

the database will be dropped including all your data when you recreate the DDL scripts and execute

them.

          However remember that you can extend the DDL generation capabilities of the Entity Framework. 

The good news is that these two limitation can be overcome using the Entity Designer Database 

Generation Power Pack. Using this power pack, you can update an existing database and synchronize 

the model with it and also make changes to the model and deploy the changes back to the database 

without data loss. Hopefully in the next version, this will be added to the core of EF.