Loading Related Entities - EF6 | Microsoft Docs
associations and navigation properties, patterns to load related entities in the Entity Depending on the relationship set in the database, the Entity Data Model . Here you will learn how to load related entities in an entity graph explicitly. Explicit loading is valid in EF 6 and EF Core both. Even with lazy loading disabled (in. Entity Framework supports three ways to load related data - eager posts // using a string to specify the relationship var blog2 = posavski-obzor.info
This is done when setting up the options for your context - typically in DbContext. OnConfiguring, or in Startup. You can explicitly load a navigation property via the DbContext.
If change tracking is enabled, then when loading an entity, EF Core will automatically set the navigation properties of the newly-loaded entitiy to refer to any entities already loaded, and set the navigation properties of the already-loaded entities to refer to the newly-loaded entity.
Explicit Loading in Entity Framework
Querying related entities You can also get a LINQ query that represents the contents of a navigation property. This allows you to do things such as running an aggregate operator over the related entities without loading them into memory. The simplest way to use lazy-loading is by installing the Microsoft.
- Entity Framework - Eager Loading
- Eager Loading in Entity Framework
- Loading Related Entities
Proxies package and enabling it with a call to UseLazyLoadingProxies. UseSqlServer myConnectionString ; EF Core will then enable lazy loading for any navigation property that can be overridden--that is, it must be virtual and on a class that can be inherited from.
For example, in the following entities, the Post. Posts navigation properties will be lazy-loaded. However, it requires a reference to the ILazyLoader service, which is defined in the Microsoft.
This package contains a minimal set of types so that there is very little impact in depending on it. However, to completely avoid depending on any EF Core packages in the entity types, it is possible to inject the ILazyLoader. Load method as a delegate. Entity namespace so make sure you are using that namespace. Eagerly loading multiple levels It is also possible to eagerly load multiple levels of related entities. The queries below show examples of how to do this for both collection and reference navigation properties.
Include will always bring in all related entities. When using POCO entity types, lazy loading is achieved by creating instances of derived proxy types and then overriding virtual properties to add the loading hook.
Explicit Loading Related Entities in EF 6 and EF Core
For example, when using the Blog entity class defined below, the related Posts will be loaded the first time the Posts navigation property is accessed: Most serializers work by accessing each property on an instance of a type.
Property access triggers lazy loading, so more entities get serialized. On those entities properties are accessed, and even more entities are loaded.
The following sections show how to do this. Turning off lazy loading for specific navigation properties Lazy loading of the Posts collection can be turned off by making the Posts property non-virtual: Turn off lazy loading for all entities Lazy loading can be turned off for all entities in the context by setting a flag on the Configuration property.