Note: EF Core creates entity classes only for tables and not for StoredProcedures or Views. HasConstraintName( "FK_Teacher_Standard") HasConstraintName( "FK_StudentCourse_Student") Įntity.Property(e => e.StandardId).HasDefaultValueSql( "((0))") HasConstraintName( "FK_StudentCourse_Course") The following is the generated Student entity class for the Student table. The above Scaffold-DbContext command creates entity classes for each table in the SchoolDB database and context class (by deriving DbContext) with Fluent API configurations for all the entities in the Models folder. PM> get-help scaffold-dbcontext –detailed Use the following command to get the detailed help on Scaffold-DbContext command: The -OutputDir parameter specifies the directory where we want to generate all the classes which is the Models folder in this case. We use provider for the SQL Server, so it is. The second parameter is the provider name.
#Icollection windows#
It will use Windows credentials to connect to the SQL Server. Trusted_Connection=True specifies the Windows authentication. Here, Server=.\SQLExpress refers to local SQLEXPRESS database server.ĭatabase=SchoolDB specifies the database name "SchoolDB" for which we are going to create classes. In the above command, the first parameter is a connection string which includes three parts: DB Server, database name and security info. In Visual Studio, select menu Tools -> NuGet Package Manger -> Package Manger Console and run the following command: PM> Scaffold-DbContext "Server=.\SQLExpress Database=SchoolDB Trusted_Connection=True " -OutputDir Models The following parameters can be specified with Scaffold-DbContext in Package Manager Console: Use Scaffold-DbContext to create a model based on your existing database. Let's create entity and context classes for the following SchoolDB database in the local MS SQL Server shown below. This reverse engineering command creates entity and context classes (by deriving DbContext) based on the schema of the existing database. So, we need to do reverse engineering using the Scaffold-DbContext command. Creating entity & context classes for an existing database is called Database-First approach.ĮF Core does not support visual designer for DB model and wizard to create the entity and context classes similar to EF 6.
#Icollection how to#
Here you will learn how to create the context and entity classes for an existing database in Entity Framework Core. Get => LazyLoader.Next Creating a Model for an Existing Database in Entity Framework Core However, to completely avoid depending on any EF Core packages in the entity types, it's possible to inject the ILazyLoader.Load method as a delegate. This package contains a minimal set of types so that there is little impact in depending on it. However, it requires a reference to the ILazyLoader service, which is defined in the package. This method doesn't require entity types to be inherited from or navigation properties to be virtual, and allows entity instances created with new to lazy-load once attached to a context.
For example, in the following entities, the Post.Blog and Blog.Posts navigation properties will be lazy-loaded. AddDbContext(ĮF 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: protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) The simplest way to use lazy-loading is by installing the package and enabling it with a call to UseLazyLoadingProxies. In this article Lazy loading with proxies
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