Complex Types In Entity Framework 6 Designer

Abstract

In real world we have little or no control on data stores and data feeds we deal with due to numerous reasons:

1. Age old systems
2. Third Party feeds
3. Poorly architected systems

Entity Framework (EF) is an object-relational mapper that enables .NET developers to work with relational data using domain-specific objects. It eliminates the need for most of the data-access code that developers usually write all the time to perform basic CRUD operations.

Microsoft ORM solution Entity Framework helps us to map entities using code first or EF designer options to bring in this data into existing apps easily.

This article discusses entities which are currently denormalized and the way to extract these into complex types for better maintainability and reusability.

Problem Definition

Most of the times entities we are dealing with are not in 3NF and would need to enhance it to meet our application needs. Also it is more than likely we would be reusing same entity in multiple places across the project and solution which needs additional data elements spread across multiple code files.

EF designer provides us a way to group the same using visual tools as explained below. As mentioned this is database first approach is used here and not code first.

Solution

I am using Visual Studio 2015 community edition for this demo, but concepts are very much applicable to Visual Studio 2013 too.

Step 1: Open Visual Studio 2015 or version you currently have.

Select File, then New Project


                                                                                 Figure 1

For purpose of this article I have selected console app. Enter “EmployeeComplexType” for name.
Right click Project and Select Add, then New Item.


                                                            Figure 2

Please enter Name EmployeeDataModel.


                                                                        Figure 3

Pick first option EF designer from database.


                                                                        Figure 4


                                                                                 Figure 5

Connection String EFEmployeeEntities will be stored in App.ConFigure file which is primarily used to connect to SQL Server backend that I have on my local machine.


                                                                                 Figure 6

I have created a table called Employee and included all the columns upfront. Schema details are available in the following figure.


                                                                           Figure 7

Here is schema details for Employee Table selected above.


                                             Figure 8


                                                                            Figure 9

Create New Complex Type Name by selecting name related scalar fields FirstName, Lastname, MiddleName & Salutation as shown above.

Click on “complexProperty” and change name to “EmployeeName”


                                                                           Figure 10

Repeat same process for address related fields too. After changing, the Employee entity will look as per the following Figure 1.

Here is the final result after making related changes. Please note that in case you don’t see Mapping Details window please press ctrl+2 or goto View, otherwindows, then Entity Data Model Mapping Details.


                                                                                          Figure 11

Here is a sample code that I have in my console app. Please note that the scalar properties like MiddleName and salutation are omitted for second employee(name2) while initializing. Same applies to addressline2 too.

It is not mandatory to define all scalar properties of complex type we have defined.

var name1 = new Name { FirstName = "John", MiddleName = "M", LastName = "Doe", Salutation = "Jr." };

var name2 = new Name { FirstName = "Jane", LastName = "Doe" };


var address1 = new Address
{
   AddressLine1 = "123 Elm street",
   AddressLine2 = "",
   City = "SanMateo",
   State = "CA",
   ZipCode = "94403"
};

At the same time we can’t have whole complex object be set to null too.

The following code throws an error saying “Null value for a non nullable value EmployeeAddress” during runtime.

context.Employees.Add(new Employee { EmployeeName = name1, EmployeeAddress = address1 });
context.Employees.Add(new Employee { EmployeeName = name2, EmployeeAddress = null });

Here is the final output.


                                                                      Figure 12

I hope this article helped you in understanding EF designer tool capability in defining and using complex types. Thanks until next one.