> For the complete documentation index, see [llms.txt](https://docs.umbraco.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.umbraco.com/umbraco-cms/13.latest/implementation/data-persistence.md).

# Data Persistence (CRUD)

*The Umbraco Services layer is used to query and manipulate Umbraco stored in the database*.

## Dependency injection

All services are available using their interfaces in the dependency injection container. ASP.NET Core supports dependency injection in almost every scenario.

### Constructors in classes

```csharp
    public class MyClass
    {
        private readonly IContentService _contentService;

        public MyClass(IContentService contentService)
        {
            _contentService = contentService;
        }
    }
```

### Constructors in views

```cshtml
    @inject IContentService ContentService
```

## Services

There is a service for each type of data in Umbraco.

[See here For a full list of services available](/umbraco-cms/13.latest/reference/management/services.md)


---

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