In this tutorial series, you will build an application that is used to manage a list of books & their authors. **Entity Framework Core** (EF Core) will be used as the ORM provider (as it comes pre-configured with the [startup template](https://abp.io/Templates)).
Go to the [startup template page](https://abp.io/Templates) and download a new project named `Acme.BookStore`, create the database and run the application by following the [template document](../../Getting-Started-AspNetCore-MVC-Template.md).
Define [entities](../../Entities.md) in the **domain layer** (`Acme.BookStore.Domain` project) of the solution. The main entity of the application is the `Book`:
````C#
using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
* ABP has two fundamental base classes for entities: `AggregateRoot` and `Entity`. **Aggregate Root** is one of the **Domain Driven Design (DDD)** concepts. See [entity document](../../Entities.md) for more details and best practices.
*`Book` entity inherits `AuditedAggregateRoot` which adds some auditing properties (`CreationTime`, `CreatorId`, `LastModificationTime`... etc.) on top of the `AggregateRoot` class.
*`Guid` is the **primary key type** of the `Book` entity.
* Used **data annotation attributes** in this code for EF Core mappings. Alternatively you could use EF Core's [fluent mapping API](https://docs.microsoft.com/en-us/ef/core/modeling) instead.
EF Core requires you to relate entities with your DbContext. The easiest way to do this is to add a `DbSet` property to the `BookStoreDbContext` class in the `Acme.BookStore.EntityFrameworkCore` project, as shown below:
The Startup template uses [EF Core Code First Migrations](https://docs.microsoft.com/en-us/ef/core/managing-schemas/migrations/) to create and maintain the database schema. Open the **Package Manager Console (PMC)** (under the *Tools/Nuget Package Manager* menu), select the `Acme.BookStore.EntityFrameworkCore` as the **default project** and execute the following command:
* **DTO** classes are used to **transfer data** between the *presentation layer* and the *application layer*. See the [Data Transfer Objects document](../../Data-Transfer-Objects.md) for more details.
*`BookDto` is used to transfer book data to the presentation layer in order to show the book information on the UI.
*`BookDto` is derived from the `AuditedEntityDto<Guid>` which has audit properties just like the `Book` class defined above.
*`[AutoMapFrom(typeof(Book))]` is used to create AutoMapper mapping from the `Book` class to the `BookDto` class. In this way, you get automatic convertion of `Book` objects to `BookDto` objects (instead of manually copy all properties).
*`IAsyncCrudAppService` defines common **CRUD** methods: `GetAsync`, `GetListAsync`, `CreateAsync`, `UpdateAsync` and `DeleteAsync`. It's not required to extend it. Instead, you could inherit from the empty `IApplicationService` interface and define your own methods.
*`BookAppService` injects `IRepository<Book, Guid>` which is the default repository created for the `Book` entity. ABP automatically creates repositories for each aggregate root (or entity). See the [repository document](../../Repositories.md).
*`BookAppService` uses `IObjectMapper` to convert `Book` objects to `BookDto` objects and `CreateUpdateBookDto` objects to `Book` objects. The Startup template uses the [AutoMapper](http://automapper.org/) library as object mapping provider. You defined mappings using the `AutoMapFrom` and the `AutoMapTo` attributes above. See the [AutoMapper integration document](../../AutoMapper-Integration.md) for details.
You normally create **Controllers** to expose application services as **HTTP API** endpoints. Thus allowing browser or 3rd-party clients to call them via AJAX.
The startup template is configured to run the [swagger UI](https://swagger.io/tools/swagger-ui/) using the [Swashbuckle.AspNetCore](https://github.com/domaindrivendev/Swashbuckle.AspNetCore) library. Run the application and enter `http://localhost:53929/swagger/` as URL on your browser.
It's common to call HTTP API endpoints via AJAX from the **JavaScript** side. You can use `$.ajax` or another tool to call the endpoints. However, ABP offers a better way.
ABP **dynamically** creates JavaScript **proxies** for all API endpoints. So, you can use any **endpoint** just like calling a **JavaScript function**.
You can easily test the JavaScript proxy using your favorite browser's **Developer Console** now. Run the application again, open your browser's **developer tools** (shortcut: F12), switch to the **Console** tab, type the following code and press enter:
*`acme.bookStore` is the namespace of the `BookAppService` converted to [camelCase](https://en.wikipedia.org/wiki/Camel_case).
*`book` is the conventional name for the `BookAppService` (removed AppService postfix and converted to camelCase).
*`getList` is the conventional name for the `GetListAsync` method defined in the `AsyncCrudAppService` base class (removed Async postfix and converted to camelCase).
*`{}` argument is used to send an empty object to the `GetListAsync` method which normally expects an object of type `PagedAndSortedResultRequestDto` which is used to send paging and sorting options to the server.
*`getList` function returns a `promise`. So, you can pass a callback to the `done` (or `then`) function to get the result from the server.
You can see the **book list** returned from the server. You can also check the **network** tab of the developer tools to see the client to server communication:
It's time to create something visible and usable! Instead of classic MVC, we will use the new [Razor Pages UI](https://docs.microsoft.com/en-us/aspnet/core/tutorials/razor-pages/razor-pages-start) approach which is recommended by Microsoft.
* Change the default inhertitance of the Razor View Page Model so it **inherits** from the `BookStorePageBase` class (instead of `PageModel`). The `BookStorePageBase` class which comes with the startup template and provides some shared properties/methods used by all pages.
Open the `en.json` file and add localization texts for `Menu:BookStore` and `Menu:Books` keys:
````json
{
"culture": "en",
"texts": {
//...
"Menu:BookStore": "Book Store",
"Menu:Books": "Books"
}
}
````
* ABP's localization system is built on [ASP.NET Core's standard localization](https://docs.microsoft.com/en-us/aspnet/core/fundamentals/localization) system and extends it in many ways. See the [localization document](../../Localization.md) for details.
* Localization key names are arbitrary, you can set any name. We prefer to add `Menu` namespace for menu items to distinguish from other texts. If a text is not defined in the localization file, it **fallbacks** to the localization key (ASP.NET Core's standard behavior).
Run the application and see the menu items are added to the top bar:
We will use the [Datatables.net](https://datatables.net/) JQuery plugin to show list of tables on the page. Datatables can completely work via AJAX, so it is fast and provides a good user experience. Datatables plugin is configured in the startup template, so you can directly use it in any page without including any style or script file to your page.
*`abp-script` [tag helper](https://docs.microsoft.com/en-us/aspnet/core/mvc/views/tag-helpers/intro) is used to add external **scripts** to the page. It has many additional features compared to standard `script` tag. It handles **minification** and **versioning** for example. See the [bundling & minification document](../../AspNetCore/Bundling-Minification.md) for details.
*`abp-card` and `abp-table` are **tag helpers** for Twitter Bootstrap's [card component](http://getbootstrap.com/docs/4.1/components/card/). There are many tag helpers in ABP to easily use most of the [bootstrap](https://getbootstrap.com/) components. You can also use regular HTML tags instead of these tag helpers, but using tag helpers reduces HTML code and prevents errors by help of the intellisense and compile time type checking. See the [tag helpers document](../../AspNetCore/Tag-Helpers.md).
*`abp.libs.datatables.normalizeConfiguration` is another helper function. There's no requirment to use it, but it simplifies the datatables configuration by providing conventional values for missing options.
