4/5/2023 0 Comments Asp mvc model db text![]() ![]() The controller would use your DbContext class to fetch the model and pass it to the view. It is quite common for a controller to create the DbContext. The EF context is a lot like a controller in the MVC pattern because it coordinates your data models to the database. Once the models are created, it’s time to create a class that maintains your Entity Framework Database Context. It will not unnecessarily fetch the related data until it is actually accessed, thus reducing the up-front querying of data from the database. Lazy loading is a nice feature of many ORMs because it allows you to dynamically access related data from a model. When a navigation property is defined as virtual, it can take advantage of certain Entity Framework functionality. It’s quite common to define navigational properties in a model to be virtual. The remainder of this chapter will focus on creating your models. This will be demonstrated in the next chapter. It’s time to put the M in MVC! Whether you choose Code First or Database First, interacting with your models will be the same. In this relationship, a Book can have one Author, while an Author can have many Books. To demonstrate the differences between Code First and Database First, the next two sections will build a data model that contains a Book model and a related Author model. You will need to accept the licenses agreement before it will be installed in your application. Once you find it, click the Install button. If it is not, type “Entity Framework” in the search box on the right. Because Entity Framework is so popular, it is often the first result returned. If it is not already selected, choose the Online option from the left-hand side. To install EF, right-click your project in Visual Studio and select Manage NuGet Packages. Once selected, the NuGet Package Manager will be opened. Installing Entity Framework is quite similar to how Knockout was installed using the NuGet Package Manager. The next two sections will explore both of these workflows, which will allow you to make your own decision for your projects. The power of the Code First Migrations makes this option extremely convenient for any developer who doesn’t require complete control over how the database tables are created and maintained.ĭatabase First makes it very convenient for the opposite scenario-when you want complete control over all database changes, but still want to leverage the power of an ORM. When using Code First, Entity Framework provides a nice toolset that allows you to perform Code First Migrations to automatically update your database when your models change. Or if you have an existing database, you can use the Entity Framework tools to create your initial Code First classes. Code First With Code First, you can have Entity Framework automatically create your database. Just like in Database First, the EDMX stores the information in XML. Once finished, you tell EF to create the necessary database tables, columns, and primary and foreign keys. Instead of the EDMX being generated automatically from a database design, you manually create models and define inter-model relationships using the Visual Studio designer. Model First This flow is quite similar to Database First in that your models and relationships are maintained within an EDMX file. Visual Studio provides a very nice designer that visually displays your model and relationships within it. When you use this flow, you create an EDMX file that stores your data schema, data models, and the relationship between your schema and models in XML. When the SQL is executed, EF takes the response of your query and converts the results into your models for easy access within your code.Įntity Framework provides three different workflows that you can set up and use within your project: Database First This flow is for when you have an existing database or want complete control over how your database is created and maintained. EF converts the LINQ to SQL and executes against your database. Last name: "", new => model.Entity Framework is an ORM that provides easy access to your database using LINQ that is written similarly to SQL. The first Create method simply returns the Create.cshtml view from /Views/PersonalDetails folder whose model is specified as PersonalDetail.ĬREATE.CSHTML VIEW = (Html.BeginForm()) "AutoId,FirstName,LastName,Age,Active")] PersonalDetail personalDetail) Public ActionResult Create([Bind(Include = To protect from overposting attacks, please enable the specific To insert a record into database we can use the same scaffold view Create.cshtml and Create action methods in the controller.ĬONTROLLER ACTION METHODS // GET: PersonalDetails/Create
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